| 1 | //! Global Value Numbering (GVN). |
| 2 | //! |
| 3 | //! Extends local CSE to cross-block redundancy elimination. Processes |
| 4 | //! blocks in dominator-tree preorder, maintaining a scoped hash table |
| 5 | //! of value numbers. When a block computes an expression already |
| 6 | //! available from a dominating block, the redundant instruction is |
| 7 | //! replaced with the dominating definition. |
| 8 | //! |
| 9 | //! Uses the same canonical Key structure as local CSE (cse.rs). |
| 10 | |
| 11 | use super::pass::Pass; |
| 12 | use crate::ir::inst::*; |
| 13 | use crate::ir::types::IrType; |
| 14 | use crate::ir::walk::{compute_immediate_dominators, dominator_tree_children}; |
| 15 | use std::collections::HashMap; |
| 16 | |
| 17 | pub struct Gvn; |
| 18 | |
| 19 | impl Pass for Gvn { |
| 20 | fn name(&self) -> &'static str { |
| 21 | "gvn" |
| 22 | } |
| 23 | |
| 24 | fn run(&self, module: &mut Module) -> bool { |
| 25 | let pure_calls: Vec<PureCallPolicy> = module |
| 26 | .functions |
| 27 | .iter() |
| 28 | .map(PureCallPolicy::for_function) |
| 29 | .collect(); |
| 30 | let mut changed = false; |
| 31 | for func in &mut module.functions { |
| 32 | // Sprint 15 Stage 2: congruence closure via fixpoint. |
| 33 | // After the first pass merges some values, downstream |
| 34 | // instructions may now have equivalent operands; their |
| 35 | // keys must be recomputed with the new `replacements` |
| 36 | // table. Iterating gvn_function until it stops mutating |
| 37 | // achieves the fixpoint without rewriting the per-block |
| 38 | // dominator-tree walk. Cap at 8 rounds to bound the worst |
| 39 | // case (in practice 1-2 rounds covers it). |
| 40 | let mut local_changed = false; |
| 41 | for _ in 0..8 { |
| 42 | if gvn_function(func, &pure_calls) { |
| 43 | local_changed = true; |
| 44 | } else { |
| 45 | break; |
| 46 | } |
| 47 | } |
| 48 | if local_changed { |
| 49 | changed = true; |
| 50 | } |
| 51 | } |
| 52 | changed |
| 53 | } |
| 54 | } |
| 55 | |
| 56 | /// Canonical key for value numbering (same as CSE). |
| 57 | #[derive(Debug, Clone, PartialEq, Eq, Hash)] |
| 58 | struct Key { |
| 59 | tag: u32, |
| 60 | operands: Vec<ValueId>, |
| 61 | aux: i128, |
| 62 | name: Option<String>, |
| 63 | ty: IrType, |
| 64 | } |
| 65 | |
| 66 | #[derive(Debug, Clone, Copy, PartialEq, Eq)] |
| 67 | enum PureArgPolicy { |
| 68 | ByValue, |
| 69 | ReadOnlyWrapperPtr, |
| 70 | Unsupported, |
| 71 | } |
| 72 | |
| 73 | #[derive(Debug, Clone)] |
| 74 | struct PureCallPolicy { |
| 75 | reusable: bool, |
| 76 | arg_policies: Vec<PureArgPolicy>, |
| 77 | } |
| 78 | |
| 79 | impl PureCallPolicy { |
| 80 | fn for_function(func: &Function) -> Self { |
| 81 | let arg_policies = func |
| 82 | .params |
| 83 | .iter() |
| 84 | .map(|param| classify_pure_arg(func, param)) |
| 85 | .collect::<Vec<_>>(); |
| 86 | let reusable = func.is_pure |
| 87 | && !matches!(func.return_type, IrType::Void) |
| 88 | && !func.return_type.is_ptr() |
| 89 | && arg_policies |
| 90 | .iter() |
| 91 | .all(|policy| *policy != PureArgPolicy::Unsupported) |
| 92 | && !reads_non_argument_memory(func); |
| 93 | Self { |
| 94 | reusable, |
| 95 | arg_policies, |
| 96 | } |
| 97 | } |
| 98 | } |
| 99 | |
| 100 | /// True if the function body touches any state outside of its |
| 101 | /// arguments — e.g. a module global via `GlobalAddr`, an external |
| 102 | /// call, or a runtime call that reads mutable state. |
| 103 | /// |
| 104 | /// Per F2018 15.7 a PURE function is free to *read* common blocks |
| 105 | /// and module variables; it just can't *write* them. The Fortran |
| 106 | /// `is_pure` flag therefore doesn't imply "result depends only on |
| 107 | /// arguments" — a pure recursive accumulator over a module |
| 108 | /// variable is fully legal, and GVN must not hash-cons such a call |
| 109 | /// across an intervening store to that variable. |
| 110 | /// |
| 111 | /// We conservatively reject any callee that contains a `GlobalAddr` |
| 112 | /// or a non-Internal `Call` / `RuntimeCall`. The existing |
| 113 | /// argument-policy machinery already handles the "reads through |
| 114 | /// argument pointer" case via `ReadOnlyWrapperPtr`. |
| 115 | /// External math intrinsics whose `Call` sites are pure functions of |
| 116 | /// their by-value arguments — emitting one is identical to emitting |
| 117 | /// any other equivalent one, so they don't disqualify their hosting |
| 118 | /// function from GVN's pure-call CSE policy. Names match the libm / |
| 119 | /// armfortas runtime symbols emitted by lower. |
| 120 | const PURE_EXTERNAL_INTRINSICS: &[&str] = &[ |
| 121 | // libm scalar math (single + double). |
| 122 | "sinf", "cosf", "tanf", "asinf", "acosf", "atanf", "atan2f", |
| 123 | "sinhf", "coshf", "tanhf", "expf", "expm1f", "logf", "log2f", |
| 124 | "log10f", "log1pf", "sqrtf", "cbrtf", "fabsf", "ceilf", "floorf", |
| 125 | "roundf", "truncf", "powf", "fmodf", "hypotf", "copysignf", |
| 126 | "sin", "cos", "tan", "asin", "acos", "atan", "atan2", |
| 127 | "sinh", "cosh", "tanh", "exp", "expm1", "log", "log2", |
| 128 | "log10", "log1p", "sqrt", "cbrt", "fabs", "ceil", "floor", |
| 129 | "round", "trunc", "pow", "fmod", "hypot", "copysign", |
| 130 | ]; |
| 131 | |
| 132 | fn is_pure_external_intrinsic(name: &str) -> bool { |
| 133 | PURE_EXTERNAL_INTRINSICS.contains(&name) |
| 134 | } |
| 135 | |
| 136 | fn reads_non_argument_memory(func: &Function) -> bool { |
| 137 | for block in &func.blocks { |
| 138 | for inst in &block.insts { |
| 139 | match &inst.kind { |
| 140 | InstKind::GlobalAddr(_) => return true, |
| 141 | InstKind::Call(FuncRef::External(name), _) |
| 142 | if !is_pure_external_intrinsic(name) => |
| 143 | { |
| 144 | return true; |
| 145 | } |
| 146 | InstKind::RuntimeCall(_, _) => return true, |
| 147 | _ => {} |
| 148 | } |
| 149 | } |
| 150 | } |
| 151 | false |
| 152 | } |
| 153 | |
| 154 | fn is_scalar_type(ty: &IrType) -> bool { |
| 155 | matches!(ty, IrType::Bool | IrType::Int(_) | IrType::Float(_)) |
| 156 | } |
| 157 | |
| 158 | fn inst_map(func: &Function) -> HashMap<ValueId, &Inst> { |
| 159 | func.blocks |
| 160 | .iter() |
| 161 | .flat_map(|block| block.insts.iter()) |
| 162 | .map(|inst| (inst.id, inst)) |
| 163 | .collect() |
| 164 | } |
| 165 | |
| 166 | fn classify_pure_arg(func: &Function, param: &Param) -> PureArgPolicy { |
| 167 | if !param.ty.is_ptr() { |
| 168 | return PureArgPolicy::ByValue; |
| 169 | } |
| 170 | let IrType::Ptr(inner) = ¶m.ty else { |
| 171 | return PureArgPolicy::Unsupported; |
| 172 | }; |
| 173 | if !is_scalar_type(inner.as_ref()) { |
| 174 | return PureArgPolicy::Unsupported; |
| 175 | } |
| 176 | if pointer_param_is_read_only_scalar(func, param.id) { |
| 177 | PureArgPolicy::ReadOnlyWrapperPtr |
| 178 | } else { |
| 179 | PureArgPolicy::Unsupported |
| 180 | } |
| 181 | } |
| 182 | |
| 183 | fn pointer_param_is_read_only_scalar(func: &Function, param_id: ValueId) -> bool { |
| 184 | let defs = inst_map(func); |
| 185 | let mut shadow_slots = Vec::new(); |
| 186 | |
| 187 | for block in &func.blocks { |
| 188 | for inst in &block.insts { |
| 189 | let uses = super::util::inst_uses(&inst.kind); |
| 190 | if !uses.contains(¶m_id) { |
| 191 | continue; |
| 192 | } |
| 193 | match &inst.kind { |
| 194 | InstKind::Store(value, addr) if *value == param_id => { |
| 195 | let Some(def) = defs.get(addr) else { |
| 196 | return false; |
| 197 | }; |
| 198 | match &def.kind { |
| 199 | InstKind::Alloca(slot_ty) => { |
| 200 | let IrType::Ptr(inner) = slot_ty else { |
| 201 | return false; |
| 202 | }; |
| 203 | if !is_scalar_type(inner.as_ref()) { |
| 204 | return false; |
| 205 | } |
| 206 | shadow_slots.push(*addr); |
| 207 | } |
| 208 | _ => return false, |
| 209 | } |
| 210 | } |
| 211 | // After mem2reg, the entry shadow slot often folds away and |
| 212 | // the PURE callee just reads the incoming by-ref scalar |
| 213 | // directly. |
| 214 | InstKind::Load(addr) if *addr == param_id => {} |
| 215 | _ => return false, |
| 216 | } |
| 217 | } |
| 218 | if let Some(term) = &block.terminator { |
| 219 | if super::util::terminator_uses(term).contains(¶m_id) { |
| 220 | return false; |
| 221 | } |
| 222 | } |
| 223 | } |
| 224 | |
| 225 | for slot in shadow_slots { |
| 226 | let mut alias_ptrs = Vec::new(); |
| 227 | for block in &func.blocks { |
| 228 | for inst in &block.insts { |
| 229 | let uses = super::util::inst_uses(&inst.kind); |
| 230 | if !uses.contains(&slot) { |
| 231 | continue; |
| 232 | } |
| 233 | match &inst.kind { |
| 234 | InstKind::Store(value, addr) if *value == param_id && *addr == slot => {} |
| 235 | InstKind::Load(addr) if *addr == slot => alias_ptrs.push(inst.id), |
| 236 | _ => return false, |
| 237 | } |
| 238 | } |
| 239 | if let Some(term) = &block.terminator { |
| 240 | if super::util::terminator_uses(term).contains(&slot) { |
| 241 | return false; |
| 242 | } |
| 243 | } |
| 244 | } |
| 245 | |
| 246 | for alias in alias_ptrs { |
| 247 | for block in &func.blocks { |
| 248 | for inst in &block.insts { |
| 249 | let uses = super::util::inst_uses(&inst.kind); |
| 250 | if !uses.contains(&alias) { |
| 251 | continue; |
| 252 | } |
| 253 | match &inst.kind { |
| 254 | InstKind::Load(addr) if *addr == alias => {} |
| 255 | _ => return false, |
| 256 | } |
| 257 | } |
| 258 | if let Some(term) = &block.terminator { |
| 259 | if super::util::terminator_uses(term).contains(&alias) { |
| 260 | return false; |
| 261 | } |
| 262 | } |
| 263 | } |
| 264 | } |
| 265 | } |
| 266 | |
| 267 | true |
| 268 | } |
| 269 | |
| 270 | fn wrapper_alloca_values( |
| 271 | func: &Function, |
| 272 | pure_calls: &[PureCallPolicy], |
| 273 | ) -> HashMap<ValueId, ValueId> { |
| 274 | let mut wrappers = HashMap::new(); |
| 275 | let candidates: Vec<ValueId> = func |
| 276 | .blocks |
| 277 | .iter() |
| 278 | .flat_map(|block| block.insts.iter()) |
| 279 | .filter_map(|inst| match &inst.kind { |
| 280 | InstKind::Alloca(inner_ty) if is_scalar_type(inner_ty) => Some(inst.id), |
| 281 | _ => None, |
| 282 | }) |
| 283 | .collect(); |
| 284 | |
| 285 | 'candidate: for alloca_id in candidates { |
| 286 | let mut stored_value = None; |
| 287 | |
| 288 | for scan_block in &func.blocks { |
| 289 | for scan_inst in &scan_block.insts { |
| 290 | let uses = super::util::inst_uses(&scan_inst.kind); |
| 291 | if !uses.contains(&alloca_id) { |
| 292 | continue; |
| 293 | } |
| 294 | match &scan_inst.kind { |
| 295 | InstKind::Store(value, addr) if *addr == alloca_id => { |
| 296 | if stored_value.replace(*value).is_some() { |
| 297 | continue 'candidate; |
| 298 | } |
| 299 | } |
| 300 | InstKind::Call(FuncRef::Internal(idx), args) => { |
| 301 | let Some(policy) = pure_calls.get(*idx as usize) else { |
| 302 | continue 'candidate; |
| 303 | }; |
| 304 | if !policy.reusable { |
| 305 | continue 'candidate; |
| 306 | } |
| 307 | let valid_arg = args.iter().enumerate().any(|(arg_idx, arg)| { |
| 308 | *arg == alloca_id |
| 309 | && policy.arg_policies.get(arg_idx).copied() |
| 310 | == Some(PureArgPolicy::ReadOnlyWrapperPtr) |
| 311 | }); |
| 312 | if !valid_arg { |
| 313 | continue 'candidate; |
| 314 | } |
| 315 | } |
| 316 | _ => continue 'candidate, |
| 317 | } |
| 318 | } |
| 319 | if let Some(term) = &scan_block.terminator { |
| 320 | if super::util::terminator_uses(term).contains(&alloca_id) { |
| 321 | continue 'candidate; |
| 322 | } |
| 323 | } |
| 324 | } |
| 325 | |
| 326 | if let Some(value) = stored_value { |
| 327 | wrappers.insert(alloca_id, value); |
| 328 | } |
| 329 | } |
| 330 | |
| 331 | wrappers |
| 332 | } |
| 333 | |
| 334 | fn resolve_value(map: &HashMap<ValueId, ValueId>, mut value: ValueId) -> ValueId { |
| 335 | while let Some(&next) = map.get(&value) { |
| 336 | if next == value { |
| 337 | break; |
| 338 | } |
| 339 | value = next; |
| 340 | } |
| 341 | value |
| 342 | } |
| 343 | |
| 344 | /// Tag identifying an associative+commutative integer/bitwise op. |
| 345 | /// Used to detect when an operand of an outer op of the same kind can |
| 346 | /// be flattened into a multi-operand list. FP ops are intentionally |
| 347 | /// excluded — under default rounding mode `(a+b)+c` is not equivalent |
| 348 | /// to `a+(b+c)`, so reordering would change results. |
| 349 | fn assoc_tag(kind: &InstKind) -> Option<u32> { |
| 350 | match kind { |
| 351 | InstKind::IAdd(..) => Some(1), |
| 352 | InstKind::IMul(..) => Some(3), |
| 353 | InstKind::And(..) => Some(30), |
| 354 | InstKind::Or(..) => Some(31), |
| 355 | InstKind::BitAnd(..) => Some(40), |
| 356 | InstKind::BitOr(..) => Some(41), |
| 357 | InstKind::BitXor(..) => Some(42), |
| 358 | _ => None, |
| 359 | } |
| 360 | } |
| 361 | |
| 362 | fn assoc_inputs(kind: &InstKind) -> Option<(ValueId, ValueId)> { |
| 363 | match kind { |
| 364 | InstKind::IAdd(a, b) |
| 365 | | InstKind::IMul(a, b) |
| 366 | | InstKind::And(a, b) |
| 367 | | InstKind::Or(a, b) |
| 368 | | InstKind::BitAnd(a, b) |
| 369 | | InstKind::BitOr(a, b) |
| 370 | | InstKind::BitXor(a, b) => Some((*a, *b)), |
| 371 | _ => None, |
| 372 | } |
| 373 | } |
| 374 | |
| 375 | /// Walk `a` and `b`, expanding any operand whose defining instruction |
| 376 | /// is the same associative-commutative op (after replacements). The |
| 377 | /// returned vector is sorted by ValueId so reorderings of the same |
| 378 | /// chain hash identically. `(a+b)+c` and `a+(b+c)` both flatten to |
| 379 | /// the sorted multiset `{a, b, c}`. |
| 380 | fn flatten_assoc( |
| 381 | tag: u32, |
| 382 | a: ValueId, |
| 383 | b: ValueId, |
| 384 | defs: &HashMap<ValueId, &Inst>, |
| 385 | replacements: &HashMap<ValueId, ValueId>, |
| 386 | ) -> Vec<ValueId> { |
| 387 | let mut out = Vec::new(); |
| 388 | let push = |v: ValueId, out: &mut Vec<ValueId>, defs: &HashMap<ValueId, &Inst>| { |
| 389 | let r = resolve_value(replacements, v); |
| 390 | if let Some(inst) = defs.get(&r) { |
| 391 | if assoc_tag(&inst.kind) == Some(tag) { |
| 392 | if let Some((aa, bb)) = assoc_inputs(&inst.kind) { |
| 393 | out.extend(flatten_assoc(tag, aa, bb, defs, replacements)); |
| 394 | return; |
| 395 | } |
| 396 | } |
| 397 | } |
| 398 | out.push(r); |
| 399 | }; |
| 400 | push(a, &mut out, defs); |
| 401 | push(b, &mut out, defs); |
| 402 | out.sort_by_key(|v| v.0); |
| 403 | out |
| 404 | } |
| 405 | |
| 406 | fn key_of( |
| 407 | inst: &Inst, |
| 408 | replacements: &HashMap<ValueId, ValueId>, |
| 409 | pure_calls: &[PureCallPolicy], |
| 410 | wrapper_values: &HashMap<ValueId, ValueId>, |
| 411 | defs: &HashMap<ValueId, &Inst>, |
| 412 | ) -> Option<Key> { |
| 413 | let mk = |tag: u32, ops: Vec<ValueId>, aux: i128| -> Option<Key> { |
| 414 | Some(Key { |
| 415 | tag, |
| 416 | operands: ops, |
| 417 | aux, |
| 418 | name: None, |
| 419 | ty: inst.ty.clone(), |
| 420 | }) |
| 421 | }; |
| 422 | let mk_named = |tag: u32, name: String| -> Option<Key> { |
| 423 | Some(Key { |
| 424 | tag, |
| 425 | operands: vec![], |
| 426 | aux: 0, |
| 427 | name: Some(name), |
| 428 | ty: inst.ty.clone(), |
| 429 | }) |
| 430 | }; |
| 431 | let remap = |v: ValueId| resolve_value(replacements, v); |
| 432 | fn canon(a: ValueId, b: ValueId) -> Vec<ValueId> { |
| 433 | if a.0 <= b.0 { |
| 434 | vec![a, b] |
| 435 | } else { |
| 436 | vec![b, a] |
| 437 | } |
| 438 | } |
| 439 | |
| 440 | match &inst.kind { |
| 441 | // Pure arithmetic — associative+commutative ops are flattened |
| 442 | // and sorted so `(a+b)+c` ≡ `a+(b+c)` ≡ `b+(a+c)` etc. |
| 443 | InstKind::IAdd(a, b) => mk(1, flatten_assoc(1, *a, *b, defs, replacements), 0), |
| 444 | InstKind::ISub(a, b) => mk(2, vec![remap(*a), remap(*b)], 0), |
| 445 | InstKind::IMul(a, b) => mk(3, flatten_assoc(3, *a, *b, defs, replacements), 0), |
| 446 | InstKind::IDiv(a, b) => mk(4, vec![remap(*a), remap(*b)], 0), |
| 447 | InstKind::IMod(a, b) => mk(5, vec![remap(*a), remap(*b)], 0), |
| 448 | InstKind::INeg(a) => mk(6, vec![remap(*a)], 0), |
| 449 | InstKind::FAdd(a, b) => mk(10, canon(remap(*a), remap(*b)), 0), |
| 450 | InstKind::FSub(a, b) => mk(11, vec![remap(*a), remap(*b)], 0), |
| 451 | InstKind::FMul(a, b) => mk(12, canon(remap(*a), remap(*b)), 0), |
| 452 | InstKind::FDiv(a, b) => mk(13, vec![remap(*a), remap(*b)], 0), |
| 453 | InstKind::FNeg(a) => mk(14, vec![remap(*a)], 0), |
| 454 | InstKind::FAbs(a) => mk(15, vec![remap(*a)], 0), |
| 455 | InstKind::FSqrt(a) => mk(16, vec![remap(*a)], 0), |
| 456 | InstKind::FPow(a, b) => mk(17, vec![remap(*a), remap(*b)], 0), |
| 457 | InstKind::ICmp(op, a, b) => { |
| 458 | let op_val = *op as i128; |
| 459 | match op { |
| 460 | CmpOp::Eq | CmpOp::Ne => mk(20, canon(remap(*a), remap(*b)), op_val), |
| 461 | _ => mk(20, vec![remap(*a), remap(*b)], op_val), |
| 462 | } |
| 463 | } |
| 464 | InstKind::FCmp(op, a, b) => mk(21, vec![remap(*a), remap(*b)], *op as i128), |
| 465 | InstKind::And(a, b) => mk(30, flatten_assoc(30, *a, *b, defs, replacements), 0), |
| 466 | InstKind::Or(a, b) => mk(31, flatten_assoc(31, *a, *b, defs, replacements), 0), |
| 467 | InstKind::Not(a) => mk(32, vec![remap(*a)], 0), |
| 468 | InstKind::Select(c, t, f) => mk(33, vec![remap(*c), remap(*t), remap(*f)], 0), |
| 469 | InstKind::BitAnd(a, b) => mk(40, flatten_assoc(40, *a, *b, defs, replacements), 0), |
| 470 | InstKind::BitOr(a, b) => mk(41, flatten_assoc(41, *a, *b, defs, replacements), 0), |
| 471 | InstKind::BitXor(a, b) => mk(42, flatten_assoc(42, *a, *b, defs, replacements), 0), |
| 472 | InstKind::BitNot(a) => mk(43, vec![remap(*a)], 0), |
| 473 | InstKind::Shl(a, b) => mk(44, vec![remap(*a), remap(*b)], 0), |
| 474 | InstKind::LShr(a, b) => mk(45, vec![remap(*a), remap(*b)], 0), |
| 475 | InstKind::AShr(a, b) => mk(46, vec![remap(*a), remap(*b)], 0), |
| 476 | InstKind::CountLeadingZeros(a) => mk(47, vec![remap(*a)], 0), |
| 477 | InstKind::CountTrailingZeros(a) => mk(48, vec![remap(*a)], 0), |
| 478 | InstKind::PopCount(a) => mk(49, vec![remap(*a)], 0), |
| 479 | // Conversions. |
| 480 | InstKind::IntToFloat(a, w) => mk(50, vec![remap(*a)], w.bits() as i128), |
| 481 | InstKind::FloatToInt(a, w) => mk(51, vec![remap(*a)], w.bits() as i128), |
| 482 | InstKind::FloatExtend(a, w) => mk(52, vec![remap(*a)], w.bits() as i128), |
| 483 | InstKind::FloatTrunc(a, w) => mk(53, vec![remap(*a)], w.bits() as i128), |
| 484 | InstKind::IntExtend(a, w, s) => mk( |
| 485 | 54, |
| 486 | vec![remap(*a)], |
| 487 | (w.bits() as i128) * if *s { 1 } else { -1 }, |
| 488 | ), |
| 489 | InstKind::IntTrunc(a, w) => mk(55, vec![remap(*a)], w.bits() as i128), |
| 490 | InstKind::PtrToInt(a) => mk(56, vec![remap(*a)], 0), |
| 491 | InstKind::IntToPtr(a, _) => mk(57, vec![remap(*a)], 0), |
| 492 | // Constants. |
| 493 | InstKind::ConstInt(v, w) => { |
| 494 | let bits = w.bits(); |
| 495 | let signed = if bits >= 128 { |
| 496 | *v |
| 497 | } else { |
| 498 | let shift = 128 - bits; |
| 499 | (*v << shift) >> shift |
| 500 | }; |
| 501 | mk(60, vec![], signed) |
| 502 | } |
| 503 | InstKind::ConstFloat(v, w) => mk(61, vec![], ((*v).to_bits() as i128) ^ (w.bits() as i128)), |
| 504 | InstKind::ConstBool(v) => mk(62, vec![], *v as i128), |
| 505 | // GlobalAddr. |
| 506 | InstKind::GlobalAddr(name) => mk_named(70, name.clone()), |
| 507 | // GEP. |
| 508 | InstKind::GetElementPtr(base, idxs) => { |
| 509 | let mut ops = vec![remap(*base)]; |
| 510 | ops.extend(idxs.iter().copied().map(remap)); |
| 511 | mk(80, ops, 0) |
| 512 | } |
| 513 | // Reusable PURE calls: by-value arguments only, real value return, |
| 514 | // and no pointer result identity to preserve. For lowered |
| 515 | // Fortran scalar-by-reference args, look through the wrapper |
| 516 | // alloca to the stored SSA value when the callee only reads the |
| 517 | // pointee as a scalar input. |
| 518 | InstKind::Call(FuncRef::Internal(idx), args) => { |
| 519 | let policy = pure_calls.get(*idx as usize)?; |
| 520 | if !policy.reusable || policy.arg_policies.len() != args.len() { |
| 521 | return None; |
| 522 | } |
| 523 | let mut ops = Vec::with_capacity(args.len()); |
| 524 | for (arg, arg_policy) in args.iter().zip(policy.arg_policies.iter()) { |
| 525 | match arg_policy { |
| 526 | PureArgPolicy::ByValue => ops.push(remap(*arg)), |
| 527 | PureArgPolicy::ReadOnlyWrapperPtr => { |
| 528 | let wrapper = remap(*arg); |
| 529 | let stored = wrapper_values.get(&wrapper)?; |
| 530 | ops.push(remap(*stored)); |
| 531 | } |
| 532 | PureArgPolicy::Unsupported => return None, |
| 533 | } |
| 534 | } |
| 535 | mk(90, ops, *idx as i128) |
| 536 | } |
| 537 | // Impure: loads, stores, runtime calls, external calls, alloca — not GVN candidates. |
| 538 | InstKind::Load(..) |
| 539 | | InstKind::Store(..) |
| 540 | | InstKind::Alloca(..) |
| 541 | | InstKind::Call(..) |
| 542 | | InstKind::RuntimeCall(..) |
| 543 | | InstKind::ConstString(..) |
| 544 | | InstKind::Undef(..) |
| 545 | | InstKind::ExtractField(..) |
| 546 | | InstKind::InsertField(..) => None, |
| 547 | |
| 548 | // Vector ops opt out of GVN until the vectorizer lands and we |
| 549 | // can characterize aliasing / commutativity properly. Same |
| 550 | // policy as CSE keying. |
| 551 | InstKind::VAdd(..) |
| 552 | | InstKind::VSub(..) |
| 553 | | InstKind::VMul(..) |
| 554 | | InstKind::VDiv(..) |
| 555 | | InstKind::VNeg(..) |
| 556 | | InstKind::VAbs(..) |
| 557 | | InstKind::VSqrt(..) |
| 558 | | InstKind::VFma(..) |
| 559 | | InstKind::VSelect(..) |
| 560 | | InstKind::VMin(..) |
| 561 | | InstKind::VMax(..) |
| 562 | | InstKind::VICmp(..) |
| 563 | | InstKind::VFCmp(..) |
| 564 | | InstKind::VLoad(..) |
| 565 | | InstKind::VStore(..) |
| 566 | | InstKind::VBitcast(..) |
| 567 | | InstKind::VExtract(..) |
| 568 | | InstKind::VInsert(..) |
| 569 | | InstKind::VBroadcast(..) |
| 570 | | InstKind::VReduceSum(..) |
| 571 | | InstKind::VReduceMin(..) |
| 572 | | InstKind::VReduceMax(..) => None, |
| 573 | } |
| 574 | } |
| 575 | |
| 576 | fn gvn_function(func: &mut Function, pure_calls: &[PureCallPolicy]) -> bool { |
| 577 | let idoms = compute_immediate_dominators(func); |
| 578 | let children = dominator_tree_children(&idoms); |
| 579 | let wrapper_values = wrapper_alloca_values(func, pure_calls); |
| 580 | let defs = inst_map(func); |
| 581 | |
| 582 | // Scoped value number table: Key → dominating ValueId. |
| 583 | let mut vn_table: HashMap<Key, ValueId> = HashMap::new(); |
| 584 | // Replacement map: redundant ValueId → dominating ValueId. |
| 585 | let mut replacements: HashMap<ValueId, ValueId> = HashMap::new(); |
| 586 | |
| 587 | // Process blocks in dominator-tree preorder (DFS from entry). |
| 588 | let mut stack = vec![(func.entry, 0usize)]; // (block, depth for scope management) |
| 589 | let mut scope_stack: Vec<Vec<Key>> = Vec::new(); // keys to remove when leaving scope |
| 590 | |
| 591 | while let Some((block_id, depth)) = stack.pop() { |
| 592 | // Pop scope entries for blocks we've left. |
| 593 | while scope_stack.len() > depth { |
| 594 | if let Some(keys) = scope_stack.pop() { |
| 595 | for key in keys { |
| 596 | vn_table.remove(&key); |
| 597 | } |
| 598 | } |
| 599 | } |
| 600 | |
| 601 | // Process this block's instructions. |
| 602 | let mut new_keys = Vec::new(); |
| 603 | let block = func.block(block_id); |
| 604 | for inst in &block.insts { |
| 605 | if let Some(key) = key_of(inst, &replacements, pure_calls, &wrapper_values, &defs) { |
| 606 | if let Some(&existing) = vn_table.get(&key) { |
| 607 | // This expression is already available from a dominating block. |
| 608 | replacements.insert(inst.id, existing); |
| 609 | } else { |
| 610 | // First occurrence — register in the table. |
| 611 | vn_table.insert(key.clone(), inst.id); |
| 612 | new_keys.push(key); |
| 613 | } |
| 614 | } |
| 615 | } |
| 616 | |
| 617 | scope_stack.push(new_keys); |
| 618 | |
| 619 | // Push children (reverse order so leftmost child is processed first). |
| 620 | if let Some(kids) = children.get(&block_id) { |
| 621 | for &child in kids.iter().rev() { |
| 622 | stack.push((child, depth + 1)); |
| 623 | } |
| 624 | } |
| 625 | } |
| 626 | |
| 627 | if replacements.is_empty() { |
| 628 | return false; |
| 629 | } |
| 630 | |
| 631 | // Apply replacements: substitute all uses of redundant values, then |
| 632 | // drop the now-dead duplicate instructions directly. This matters |
| 633 | // for PURE calls because DCE conservatively treats generic calls as |
| 634 | // side-effecting. |
| 635 | for block in &mut func.blocks { |
| 636 | for inst in &mut block.insts { |
| 637 | inst.kind = remap_operands(&inst.kind, &replacements); |
| 638 | } |
| 639 | block |
| 640 | .insts |
| 641 | .retain(|inst| !replacements.contains_key(&inst.id)); |
| 642 | if let Some(ref mut term) = block.terminator { |
| 643 | remap_terminator_operands(term, &replacements); |
| 644 | } |
| 645 | } |
| 646 | |
| 647 | true |
| 648 | } |
| 649 | |
| 650 | /// Remap operands in an instruction using the replacement map. |
| 651 | fn remap_operands(kind: &InstKind, map: &HashMap<ValueId, ValueId>) -> InstKind { |
| 652 | super::loop_utils::remap_inst_kind(kind, map) |
| 653 | } |
| 654 | |
| 655 | /// Remap operands in a terminator. |
| 656 | fn remap_terminator_operands(term: &mut Terminator, map: &HashMap<ValueId, ValueId>) { |
| 657 | let r = |v: &ValueId| *map.get(v).unwrap_or(v); |
| 658 | match term { |
| 659 | Terminator::Return(Some(v)) => *v = r(v), |
| 660 | Terminator::Branch(_, args) => { |
| 661 | for a in args.iter_mut() { |
| 662 | *a = r(a); |
| 663 | } |
| 664 | } |
| 665 | Terminator::CondBranch { |
| 666 | cond, |
| 667 | true_args, |
| 668 | false_args, |
| 669 | .. |
| 670 | } => { |
| 671 | *cond = r(cond); |
| 672 | for a in true_args.iter_mut() { |
| 673 | *a = r(a); |
| 674 | } |
| 675 | for a in false_args.iter_mut() { |
| 676 | *a = r(a); |
| 677 | } |
| 678 | } |
| 679 | Terminator::Switch { selector, .. } => { |
| 680 | *selector = r(selector); |
| 681 | } |
| 682 | _ => {} |
| 683 | } |
| 684 | } |
| 685 | |
| 686 | #[cfg(test)] |
| 687 | mod tests { |
| 688 | use super::*; |
| 689 | use crate::ir::lower; |
| 690 | use crate::ir::types::{IntWidth, IrType}; |
| 691 | use crate::lexer::{tokenize, SourceForm}; |
| 692 | use crate::lexer::{Position, Span}; |
| 693 | use crate::opt::pass::Pass; |
| 694 | use crate::opt::pass::PassManager; |
| 695 | use crate::opt::pipeline::OptLevel; |
| 696 | use crate::opt::{ |
| 697 | bce::Bce, call_resolve::CallResolve, const_fold::ConstFold, const_prop::ConstProp, |
| 698 | dead_func::DeadFuncElim, dse::Dse, fission::LoopFission, fusion::LoopFusion, |
| 699 | global_lsf::GlobalLsf, inline::Inline, interchange::LoopInterchange, licm::Licm, |
| 700 | lsf::LocalLsf, mem2reg::Mem2Reg, peel::LoopPeel, preheader::PreheaderInsert, |
| 701 | simplify_cfg::SimplifyCfg, sroa::Sroa, strength_reduce::StrengthReduce, unroll::LoopUnroll, |
| 702 | unswitch::LoopUnswitch, |
| 703 | }; |
| 704 | use crate::parser::Parser; |
| 705 | use crate::preprocess::PreprocConfig; |
| 706 | use crate::sema::{resolve, validate}; |
| 707 | use std::fs; |
| 708 | use std::path::PathBuf; |
| 709 | |
| 710 | fn span() -> Span { |
| 711 | let pos = Position { line: 0, col: 0 }; |
| 712 | Span { |
| 713 | file_id: 0, |
| 714 | start: pos, |
| 715 | end: pos, |
| 716 | } |
| 717 | } |
| 718 | |
| 719 | fn push_inst(func: &mut Function, block: BlockId, kind: InstKind, ty: IrType) -> ValueId { |
| 720 | let id = func.next_value_id(); |
| 721 | func.register_type(id, ty.clone()); |
| 722 | func.block_mut(block).insts.push(Inst { |
| 723 | id, |
| 724 | kind, |
| 725 | ty, |
| 726 | span: span(), |
| 727 | }); |
| 728 | id |
| 729 | } |
| 730 | |
| 731 | fn lower_fixture(name: &str) -> Module { |
| 732 | let path = PathBuf::from("test_programs").join(name); |
| 733 | let source = fs::read_to_string(&path).expect("fixture source"); |
| 734 | let pp = crate::preprocess::preprocess( |
| 735 | &source, |
| 736 | &PreprocConfig { |
| 737 | filename: path.to_string_lossy().into_owned(), |
| 738 | fixed_form: false, |
| 739 | ..PreprocConfig::default() |
| 740 | }, |
| 741 | ) |
| 742 | .expect("preprocess fixture"); |
| 743 | let tokens = tokenize(&pp.text, 0, SourceForm::FreeForm).expect("tokenize fixture"); |
| 744 | let mut parser = Parser::new(&tokens); |
| 745 | let units = parser.parse_file().expect("parse fixture"); |
| 746 | let (st, type_layouts) = { |
| 747 | let rr = resolve::resolve_file(&units, &[]).expect("resolve fixture"); |
| 748 | (rr.st, rr.type_layouts) |
| 749 | }; |
| 750 | let diags = validate::validate_file(&units, &st); |
| 751 | assert!( |
| 752 | !diags |
| 753 | .iter() |
| 754 | .any(|diag| diag.kind == validate::DiagKind::Error), |
| 755 | "fixture should lower cleanly: {:?}", |
| 756 | diags |
| 757 | ); |
| 758 | lower::lower_file( |
| 759 | &units, |
| 760 | &st, |
| 761 | &type_layouts, |
| 762 | std::collections::HashMap::new(), |
| 763 | std::collections::HashMap::new(), |
| 764 | std::collections::HashMap::new(), |
| 765 | std::collections::HashMap::new(), |
| 766 | ) |
| 767 | .0 |
| 768 | } |
| 769 | |
| 770 | fn build_pre_gvn_o2_pipeline() -> PassManager { |
| 771 | let mut pm = PassManager::new(); |
| 772 | pm.add(Box::new(CallResolve)); |
| 773 | pm.add(Box::new(Mem2Reg)); |
| 774 | pm.add(Box::new(ConstFold)); |
| 775 | pm.add(Box::new(Sroa)); |
| 776 | pm.add(Box::new(Mem2Reg)); |
| 777 | pm.add(Box::new(Inline::for_level(OptLevel::O2))); |
| 778 | pm.add(Box::new(SimplifyCfg)); |
| 779 | pm.add(Box::new(DeadFuncElim)); |
| 780 | pm.add(Box::new(Bce)); |
| 781 | pm.add(Box::new(StrengthReduce)); |
| 782 | pm.add(Box::new(LocalLsf)); |
| 783 | pm.add(Box::new(GlobalLsf)); |
| 784 | pm.add(Box::new(crate::opt::cse::LocalCse)); |
| 785 | pm.add(Box::new(PreheaderInsert)); |
| 786 | pm.add(Box::new(LoopPeel)); |
| 787 | pm.add(Box::new(LoopUnswitch)); |
| 788 | pm.add(Box::new(Licm)); |
| 789 | pm.add(Box::new(ConstProp)); |
| 790 | pm.add(Box::new(Dse)); |
| 791 | pm.add(Box::new(LoopInterchange)); |
| 792 | pm.add(Box::new(LoopFission)); |
| 793 | pm.add(Box::new(LoopFusion)); |
| 794 | pm.add(Box::new(LoopUnroll)); |
| 795 | pm |
| 796 | } |
| 797 | |
| 798 | #[test] |
| 799 | fn gvn_associativity_folds_left_and_right_regroups() { |
| 800 | // r1 = (a + b) + c |
| 801 | // r2 = a + (b + c) |
| 802 | // After GVN, r2 should be replaced by r1 (or vice versa) — the |
| 803 | // pass should detect at least one redundancy. |
| 804 | let mut m = Module::new("test".into()); |
| 805 | let mut f = Function::new("test".into(), vec![], IrType::Int(IntWidth::I32)); |
| 806 | let entry = f.entry; |
| 807 | let i32t = IrType::Int(IntWidth::I32); |
| 808 | let a = push_inst(&mut f, entry, InstKind::ConstInt(7, IntWidth::I32), i32t.clone()); |
| 809 | let b = push_inst(&mut f, entry, InstKind::ConstInt(11, IntWidth::I32), i32t.clone()); |
| 810 | let c = push_inst(&mut f, entry, InstKind::ConstInt(13, IntWidth::I32), i32t.clone()); |
| 811 | // (a + b) + c |
| 812 | let ab = push_inst(&mut f, entry, InstKind::IAdd(a, b), i32t.clone()); |
| 813 | let r1 = push_inst(&mut f, entry, InstKind::IAdd(ab, c), i32t.clone()); |
| 814 | // a + (b + c) |
| 815 | let bc = push_inst(&mut f, entry, InstKind::IAdd(b, c), i32t.clone()); |
| 816 | let r2 = push_inst(&mut f, entry, InstKind::IAdd(a, bc), i32t.clone()); |
| 817 | // Use both so DCE doesn't strip them: sum = r1 + r2 |
| 818 | let sum = push_inst(&mut f, entry, InstKind::IAdd(r1, r2), i32t.clone()); |
| 819 | f.block_mut(entry).terminator = Some(Terminator::Return(Some(sum))); |
| 820 | m.add_function(f); |
| 821 | |
| 822 | let pass = Gvn; |
| 823 | let changed = pass.run(&mut m); |
| 824 | assert!( |
| 825 | changed, |
| 826 | "GVN should detect that (a+b)+c and a+(b+c) are the same value" |
| 827 | ); |
| 828 | } |
| 829 | |
| 830 | #[test] |
| 831 | fn gvn_no_op_on_empty() { |
| 832 | let mut m = Module::new("test".into()); |
| 833 | let mut f = Function::new("test".into(), vec![], IrType::Void); |
| 834 | f.block_mut(f.entry).terminator = Some(Terminator::Return(None)); |
| 835 | m.add_function(f); |
| 836 | let pass = Gvn; |
| 837 | assert!(!pass.run(&mut m)); |
| 838 | } |
| 839 | |
| 840 | #[test] |
| 841 | fn gvn_handles_max_i128_constant_keys() { |
| 842 | let mut m = Module::new("test".into()); |
| 843 | let mut f = Function::new("test".into(), vec![], IrType::Int(IntWidth::I128)); |
| 844 | let entry = f.entry; |
| 845 | let wide = push_inst( |
| 846 | &mut f, |
| 847 | entry, |
| 848 | InstKind::ConstInt(i128::MAX, IntWidth::I128), |
| 849 | IrType::Int(IntWidth::I128), |
| 850 | ); |
| 851 | f.block_mut(entry).terminator = Some(Terminator::Return(Some(wide))); |
| 852 | m.add_function(f); |
| 853 | let pass = Gvn; |
| 854 | assert!( |
| 855 | !pass.run(&mut m), |
| 856 | "single max-i128 constant should not produce a spurious rewrite" |
| 857 | ); |
| 858 | } |
| 859 | |
| 860 | #[test] |
| 861 | fn gvn_reuses_pure_by_value_calls() { |
| 862 | let mut m = Module::new("test".into()); |
| 863 | |
| 864 | let param = Param { |
| 865 | name: "x".into(), |
| 866 | ty: IrType::Int(IntWidth::I32), |
| 867 | id: ValueId(0), |
| 868 | fortran_noalias: false, |
| 869 | }; |
| 870 | let mut callee = Function::new("square".into(), vec![param], IrType::Int(IntWidth::I32)); |
| 871 | callee.is_pure = true; |
| 872 | callee.block_mut(callee.entry).terminator = Some(Terminator::Return(Some(ValueId(0)))); |
| 873 | m.add_function(callee); |
| 874 | |
| 875 | let mut caller = Function::new("main".into(), vec![], IrType::Int(IntWidth::I32)); |
| 876 | let entry = caller.entry; |
| 877 | let c7 = push_inst( |
| 878 | &mut caller, |
| 879 | entry, |
| 880 | InstKind::ConstInt(7, IntWidth::I32), |
| 881 | IrType::Int(IntWidth::I32), |
| 882 | ); |
| 883 | let call1 = push_inst( |
| 884 | &mut caller, |
| 885 | entry, |
| 886 | InstKind::Call(FuncRef::Internal(0), vec![c7]), |
| 887 | IrType::Int(IntWidth::I32), |
| 888 | ); |
| 889 | let call2 = push_inst( |
| 890 | &mut caller, |
| 891 | entry, |
| 892 | InstKind::Call(FuncRef::Internal(0), vec![c7]), |
| 893 | IrType::Int(IntWidth::I32), |
| 894 | ); |
| 895 | let sum = push_inst( |
| 896 | &mut caller, |
| 897 | entry, |
| 898 | InstKind::IAdd(call1, call2), |
| 899 | IrType::Int(IntWidth::I32), |
| 900 | ); |
| 901 | caller.block_mut(entry).terminator = Some(Terminator::Return(Some(sum))); |
| 902 | m.add_function(caller); |
| 903 | |
| 904 | let pass = Gvn; |
| 905 | assert!(pass.run(&mut m)); |
| 906 | |
| 907 | let caller = &m.functions[1]; |
| 908 | let calls: Vec<&Inst> = caller.blocks[0] |
| 909 | .insts |
| 910 | .iter() |
| 911 | .filter(|inst| matches!(inst.kind, InstKind::Call(..))) |
| 912 | .collect(); |
| 913 | assert_eq!(calls.len(), 1, "redundant PURE call should be removed"); |
| 914 | let kept_call = calls[0].id; |
| 915 | |
| 916 | let add = caller.blocks[0] |
| 917 | .insts |
| 918 | .iter() |
| 919 | .find(|inst| matches!(inst.kind, InstKind::IAdd(..))) |
| 920 | .expect("caller should still contain the sum"); |
| 921 | match add.kind { |
| 922 | InstKind::IAdd(lhs, rhs) => { |
| 923 | assert_eq!(lhs, kept_call); |
| 924 | assert_eq!(rhs, kept_call); |
| 925 | } |
| 926 | _ => unreachable!(), |
| 927 | } |
| 928 | } |
| 929 | |
| 930 | #[test] |
| 931 | fn gvn_reuses_pure_calls_after_operand_canonicalization() { |
| 932 | let mut m = Module::new("test".into()); |
| 933 | |
| 934 | let param = Param { |
| 935 | name: "x".into(), |
| 936 | ty: IrType::Int(IntWidth::I32), |
| 937 | id: ValueId(0), |
| 938 | fortran_noalias: false, |
| 939 | }; |
| 940 | let mut callee = Function::new("square".into(), vec![param], IrType::Int(IntWidth::I32)); |
| 941 | callee.is_pure = true; |
| 942 | callee.block_mut(callee.entry).terminator = Some(Terminator::Return(Some(ValueId(0)))); |
| 943 | m.add_function(callee); |
| 944 | |
| 945 | let mut caller = Function::new("main".into(), vec![], IrType::Int(IntWidth::I32)); |
| 946 | let entry = caller.entry; |
| 947 | let a = push_inst( |
| 948 | &mut caller, |
| 949 | entry, |
| 950 | InstKind::ConstInt(3, IntWidth::I32), |
| 951 | IrType::Int(IntWidth::I32), |
| 952 | ); |
| 953 | let b = push_inst( |
| 954 | &mut caller, |
| 955 | entry, |
| 956 | InstKind::ConstInt(4, IntWidth::I32), |
| 957 | IrType::Int(IntWidth::I32), |
| 958 | ); |
| 959 | let sum1 = push_inst( |
| 960 | &mut caller, |
| 961 | entry, |
| 962 | InstKind::IAdd(a, b), |
| 963 | IrType::Int(IntWidth::I32), |
| 964 | ); |
| 965 | let sum2 = push_inst( |
| 966 | &mut caller, |
| 967 | entry, |
| 968 | InstKind::IAdd(a, b), |
| 969 | IrType::Int(IntWidth::I32), |
| 970 | ); |
| 971 | let call1 = push_inst( |
| 972 | &mut caller, |
| 973 | entry, |
| 974 | InstKind::Call(FuncRef::Internal(0), vec![sum1]), |
| 975 | IrType::Int(IntWidth::I32), |
| 976 | ); |
| 977 | let call2 = push_inst( |
| 978 | &mut caller, |
| 979 | entry, |
| 980 | InstKind::Call(FuncRef::Internal(0), vec![sum2]), |
| 981 | IrType::Int(IntWidth::I32), |
| 982 | ); |
| 983 | caller.block_mut(entry).terminator = Some(Terminator::Return(Some(call2))); |
| 984 | m.add_function(caller); |
| 985 | |
| 986 | let pass = Gvn; |
| 987 | assert!(pass.run(&mut m)); |
| 988 | |
| 989 | let caller = &m.functions[1]; |
| 990 | let call_count = caller.blocks[0] |
| 991 | .insts |
| 992 | .iter() |
| 993 | .filter(|inst| matches!(inst.kind, InstKind::Call(..))) |
| 994 | .count(); |
| 995 | assert_eq!( |
| 996 | call_count, 1, |
| 997 | "PURE call should reuse equivalent dominating args" |
| 998 | ); |
| 999 | |
| 1000 | match caller.blocks[0] |
| 1001 | .terminator |
| 1002 | .as_ref() |
| 1003 | .expect("return terminator") |
| 1004 | { |
| 1005 | Terminator::Return(Some(v)) => assert_eq!(*v, call1), |
| 1006 | other => panic!("unexpected terminator: {:?}", other), |
| 1007 | } |
| 1008 | } |
| 1009 | |
| 1010 | #[test] |
| 1011 | fn pure_pointer_param_policy_accepts_read_only_scalar_pattern() { |
| 1012 | let param = Param { |
| 1013 | name: "n".into(), |
| 1014 | ty: IrType::Ptr(Box::new(IrType::Int(IntWidth::I32))), |
| 1015 | id: ValueId(0), |
| 1016 | fortran_noalias: false, |
| 1017 | }; |
| 1018 | let mut callee = |
| 1019 | Function::new("heavy_fact".into(), vec![param], IrType::Int(IntWidth::I32)); |
| 1020 | callee.is_pure = true; |
| 1021 | let entry = callee.entry; |
| 1022 | |
| 1023 | let slot = push_inst( |
| 1024 | &mut callee, |
| 1025 | entry, |
| 1026 | InstKind::Alloca(IrType::Ptr(Box::new(IrType::Int(IntWidth::I32)))), |
| 1027 | IrType::Ptr(Box::new(IrType::Ptr(Box::new(IrType::Int(IntWidth::I32))))), |
| 1028 | ); |
| 1029 | push_inst( |
| 1030 | &mut callee, |
| 1031 | entry, |
| 1032 | InstKind::Store(ValueId(0), slot), |
| 1033 | IrType::Void, |
| 1034 | ); |
| 1035 | let arg_ptr = push_inst( |
| 1036 | &mut callee, |
| 1037 | entry, |
| 1038 | InstKind::Load(slot), |
| 1039 | IrType::Ptr(Box::new(IrType::Int(IntWidth::I32))), |
| 1040 | ); |
| 1041 | let arg_val = push_inst( |
| 1042 | &mut callee, |
| 1043 | entry, |
| 1044 | InstKind::Load(arg_ptr), |
| 1045 | IrType::Int(IntWidth::I32), |
| 1046 | ); |
| 1047 | callee.block_mut(entry).terminator = Some(Terminator::Return(Some(arg_val))); |
| 1048 | |
| 1049 | let policy = PureCallPolicy::for_function(&callee); |
| 1050 | assert!(policy.reusable); |
| 1051 | assert_eq!(policy.arg_policies, vec![PureArgPolicy::ReadOnlyWrapperPtr]); |
| 1052 | } |
| 1053 | |
| 1054 | #[test] |
| 1055 | fn wrapper_alloca_values_accept_scalar_by_ref_call_pattern() { |
| 1056 | let mut m = Module::new("test".into()); |
| 1057 | |
| 1058 | let param = Param { |
| 1059 | name: "n".into(), |
| 1060 | ty: IrType::Ptr(Box::new(IrType::Int(IntWidth::I32))), |
| 1061 | id: ValueId(0), |
| 1062 | fortran_noalias: false, |
| 1063 | }; |
| 1064 | let mut callee = |
| 1065 | Function::new("heavy_fact".into(), vec![param], IrType::Int(IntWidth::I32)); |
| 1066 | callee.is_pure = true; |
| 1067 | let callee_entry = callee.entry; |
| 1068 | let slot = push_inst( |
| 1069 | &mut callee, |
| 1070 | callee_entry, |
| 1071 | InstKind::Alloca(IrType::Ptr(Box::new(IrType::Int(IntWidth::I32)))), |
| 1072 | IrType::Ptr(Box::new(IrType::Ptr(Box::new(IrType::Int(IntWidth::I32))))), |
| 1073 | ); |
| 1074 | push_inst( |
| 1075 | &mut callee, |
| 1076 | callee_entry, |
| 1077 | InstKind::Store(ValueId(0), slot), |
| 1078 | IrType::Void, |
| 1079 | ); |
| 1080 | let arg_ptr = push_inst( |
| 1081 | &mut callee, |
| 1082 | callee_entry, |
| 1083 | InstKind::Load(slot), |
| 1084 | IrType::Ptr(Box::new(IrType::Int(IntWidth::I32))), |
| 1085 | ); |
| 1086 | let arg_val = push_inst( |
| 1087 | &mut callee, |
| 1088 | callee_entry, |
| 1089 | InstKind::Load(arg_ptr), |
| 1090 | IrType::Int(IntWidth::I32), |
| 1091 | ); |
| 1092 | callee.block_mut(callee_entry).terminator = Some(Terminator::Return(Some(arg_val))); |
| 1093 | m.add_function(callee); |
| 1094 | |
| 1095 | let pure_calls = vec![PureCallPolicy::for_function(&m.functions[0])]; |
| 1096 | |
| 1097 | let mut caller = Function::new("main".into(), vec![], IrType::Int(IntWidth::I32)); |
| 1098 | let entry = caller.entry; |
| 1099 | let c = push_inst( |
| 1100 | &mut caller, |
| 1101 | entry, |
| 1102 | InstKind::ConstInt(6, IntWidth::I32), |
| 1103 | IrType::Int(IntWidth::I32), |
| 1104 | ); |
| 1105 | let wrapper = push_inst( |
| 1106 | &mut caller, |
| 1107 | entry, |
| 1108 | InstKind::Alloca(IrType::Int(IntWidth::I32)), |
| 1109 | IrType::Ptr(Box::new(IrType::Int(IntWidth::I32))), |
| 1110 | ); |
| 1111 | push_inst( |
| 1112 | &mut caller, |
| 1113 | entry, |
| 1114 | InstKind::Store(c, wrapper), |
| 1115 | IrType::Void, |
| 1116 | ); |
| 1117 | let call = push_inst( |
| 1118 | &mut caller, |
| 1119 | entry, |
| 1120 | InstKind::Call(FuncRef::Internal(0), vec![wrapper]), |
| 1121 | IrType::Int(IntWidth::I32), |
| 1122 | ); |
| 1123 | caller.block_mut(entry).terminator = Some(Terminator::Return(Some(call))); |
| 1124 | |
| 1125 | let wrappers = wrapper_alloca_values(&caller, &pure_calls); |
| 1126 | assert_eq!(wrappers.get(&wrapper), Some(&c)); |
| 1127 | } |
| 1128 | |
| 1129 | #[test] |
| 1130 | fn gvn_reuses_pure_calls_through_scalar_wrapper_allocas() { |
| 1131 | let mut m = Module::new("test".into()); |
| 1132 | |
| 1133 | let param = Param { |
| 1134 | name: "n".into(), |
| 1135 | ty: IrType::Ptr(Box::new(IrType::Int(IntWidth::I32))), |
| 1136 | id: ValueId(0), |
| 1137 | fortran_noalias: false, |
| 1138 | }; |
| 1139 | let mut callee = |
| 1140 | Function::new("heavy_fact".into(), vec![param], IrType::Int(IntWidth::I32)); |
| 1141 | callee.is_pure = true; |
| 1142 | let callee_entry = callee.entry; |
| 1143 | let shadow = push_inst( |
| 1144 | &mut callee, |
| 1145 | callee_entry, |
| 1146 | InstKind::Alloca(IrType::Ptr(Box::new(IrType::Int(IntWidth::I32)))), |
| 1147 | IrType::Ptr(Box::new(IrType::Ptr(Box::new(IrType::Int(IntWidth::I32))))), |
| 1148 | ); |
| 1149 | push_inst( |
| 1150 | &mut callee, |
| 1151 | callee_entry, |
| 1152 | InstKind::Store(ValueId(0), shadow), |
| 1153 | IrType::Void, |
| 1154 | ); |
| 1155 | let arg_ptr = push_inst( |
| 1156 | &mut callee, |
| 1157 | callee_entry, |
| 1158 | InstKind::Load(shadow), |
| 1159 | IrType::Ptr(Box::new(IrType::Int(IntWidth::I32))), |
| 1160 | ); |
| 1161 | let arg_val = push_inst( |
| 1162 | &mut callee, |
| 1163 | callee_entry, |
| 1164 | InstKind::Load(arg_ptr), |
| 1165 | IrType::Int(IntWidth::I32), |
| 1166 | ); |
| 1167 | callee.block_mut(callee_entry).terminator = Some(Terminator::Return(Some(arg_val))); |
| 1168 | m.add_function(callee); |
| 1169 | |
| 1170 | let mut caller = Function::new("main".into(), vec![], IrType::Int(IntWidth::I32)); |
| 1171 | let entry = caller.entry; |
| 1172 | let first = push_inst( |
| 1173 | &mut caller, |
| 1174 | entry, |
| 1175 | InstKind::Alloca(IrType::Int(IntWidth::I32)), |
| 1176 | IrType::Ptr(Box::new(IrType::Int(IntWidth::I32))), |
| 1177 | ); |
| 1178 | let second = push_inst( |
| 1179 | &mut caller, |
| 1180 | entry, |
| 1181 | InstKind::Alloca(IrType::Int(IntWidth::I32)), |
| 1182 | IrType::Ptr(Box::new(IrType::Int(IntWidth::I32))), |
| 1183 | ); |
| 1184 | let c1 = push_inst( |
| 1185 | &mut caller, |
| 1186 | entry, |
| 1187 | InstKind::ConstInt(6, IntWidth::I32), |
| 1188 | IrType::Int(IntWidth::I32), |
| 1189 | ); |
| 1190 | let c2 = push_inst( |
| 1191 | &mut caller, |
| 1192 | entry, |
| 1193 | InstKind::ConstInt(6, IntWidth::I32), |
| 1194 | IrType::Int(IntWidth::I32), |
| 1195 | ); |
| 1196 | let wrap1 = push_inst( |
| 1197 | &mut caller, |
| 1198 | entry, |
| 1199 | InstKind::Alloca(IrType::Int(IntWidth::I32)), |
| 1200 | IrType::Ptr(Box::new(IrType::Int(IntWidth::I32))), |
| 1201 | ); |
| 1202 | push_inst(&mut caller, entry, InstKind::Store(c2, wrap1), IrType::Void); |
| 1203 | let call1 = push_inst( |
| 1204 | &mut caller, |
| 1205 | entry, |
| 1206 | InstKind::Call(FuncRef::Internal(0), vec![wrap1]), |
| 1207 | IrType::Int(IntWidth::I32), |
| 1208 | ); |
| 1209 | push_inst( |
| 1210 | &mut caller, |
| 1211 | entry, |
| 1212 | InstKind::Store(call1, first), |
| 1213 | IrType::Void, |
| 1214 | ); |
| 1215 | let c3 = push_inst( |
| 1216 | &mut caller, |
| 1217 | entry, |
| 1218 | InstKind::ConstInt(6, IntWidth::I32), |
| 1219 | IrType::Int(IntWidth::I32), |
| 1220 | ); |
| 1221 | let c4 = push_inst( |
| 1222 | &mut caller, |
| 1223 | entry, |
| 1224 | InstKind::ConstInt(6, IntWidth::I32), |
| 1225 | IrType::Int(IntWidth::I32), |
| 1226 | ); |
| 1227 | let wrap2 = push_inst( |
| 1228 | &mut caller, |
| 1229 | entry, |
| 1230 | InstKind::Alloca(IrType::Int(IntWidth::I32)), |
| 1231 | IrType::Ptr(Box::new(IrType::Int(IntWidth::I32))), |
| 1232 | ); |
| 1233 | push_inst(&mut caller, entry, InstKind::Store(c4, wrap2), IrType::Void); |
| 1234 | let call2 = push_inst( |
| 1235 | &mut caller, |
| 1236 | entry, |
| 1237 | InstKind::Call(FuncRef::Internal(0), vec![wrap2]), |
| 1238 | IrType::Int(IntWidth::I32), |
| 1239 | ); |
| 1240 | push_inst( |
| 1241 | &mut caller, |
| 1242 | entry, |
| 1243 | InstKind::Store(call2, second), |
| 1244 | IrType::Void, |
| 1245 | ); |
| 1246 | let left = push_inst( |
| 1247 | &mut caller, |
| 1248 | entry, |
| 1249 | InstKind::Load(first), |
| 1250 | IrType::Int(IntWidth::I32), |
| 1251 | ); |
| 1252 | let right = push_inst( |
| 1253 | &mut caller, |
| 1254 | entry, |
| 1255 | InstKind::Load(second), |
| 1256 | IrType::Int(IntWidth::I32), |
| 1257 | ); |
| 1258 | let sum = push_inst( |
| 1259 | &mut caller, |
| 1260 | entry, |
| 1261 | InstKind::IAdd(left, right), |
| 1262 | IrType::Int(IntWidth::I32), |
| 1263 | ); |
| 1264 | caller.block_mut(entry).terminator = Some(Terminator::Return(Some(sum))); |
| 1265 | m.add_function(caller); |
| 1266 | |
| 1267 | let pure_calls: Vec<PureCallPolicy> = m |
| 1268 | .functions |
| 1269 | .iter() |
| 1270 | .map(PureCallPolicy::for_function) |
| 1271 | .collect(); |
| 1272 | assert!(pure_calls[0].reusable); |
| 1273 | assert_eq!( |
| 1274 | pure_calls[0].arg_policies, |
| 1275 | vec![PureArgPolicy::ReadOnlyWrapperPtr] |
| 1276 | ); |
| 1277 | let wrappers = wrapper_alloca_values(&m.functions[1], &pure_calls); |
| 1278 | assert_eq!(wrappers.get(&wrap1), Some(&c2)); |
| 1279 | assert_eq!(wrappers.get(&wrap2), Some(&c4)); |
| 1280 | |
| 1281 | let mut replacements = HashMap::new(); |
| 1282 | replacements.insert(c2, c1); |
| 1283 | replacements.insert(c3, c1); |
| 1284 | replacements.insert(c4, c1); |
| 1285 | let caller_before = &m.functions[1]; |
| 1286 | let call1_inst = caller_before.blocks[0] |
| 1287 | .insts |
| 1288 | .iter() |
| 1289 | .find(|inst| inst.id == call1) |
| 1290 | .expect("call1 inst"); |
| 1291 | let call2_inst = caller_before.blocks[0] |
| 1292 | .insts |
| 1293 | .iter() |
| 1294 | .find(|inst| inst.id == call2) |
| 1295 | .expect("call2 inst"); |
| 1296 | let test_defs = inst_map(caller_before); |
| 1297 | let key1 = key_of(call1_inst, &replacements, &pure_calls, &wrappers, &test_defs) |
| 1298 | .expect("call1 should key"); |
| 1299 | let key2 = key_of(call2_inst, &replacements, &pure_calls, &wrappers, &test_defs) |
| 1300 | .expect("call2 should key"); |
| 1301 | assert_eq!( |
| 1302 | key1, key2, |
| 1303 | "wrapper-based call keys should line up before the pass runs" |
| 1304 | ); |
| 1305 | |
| 1306 | let pass = Gvn; |
| 1307 | assert!(pass.run(&mut m)); |
| 1308 | |
| 1309 | let caller = &m.functions[1]; |
| 1310 | let call_count = caller.blocks[0] |
| 1311 | .insts |
| 1312 | .iter() |
| 1313 | .filter(|inst| matches!(inst.kind, InstKind::Call(..))) |
| 1314 | .count(); |
| 1315 | assert_eq!(call_count, 1, "wrapper-alloca PURE calls should dedupe"); |
| 1316 | } |
| 1317 | |
| 1318 | #[test] |
| 1319 | fn gvn_reuses_pure_calls_for_recursive_factorial_shape() { |
| 1320 | let mut m = Module::new("test".into()); |
| 1321 | |
| 1322 | let param = Param { |
| 1323 | name: "n".into(), |
| 1324 | ty: IrType::Ptr(Box::new(IrType::Int(IntWidth::I32))), |
| 1325 | id: ValueId(0), |
| 1326 | fortran_noalias: false, |
| 1327 | }; |
| 1328 | let mut callee = |
| 1329 | Function::new("heavy_fact".into(), vec![param], IrType::Int(IntWidth::I32)); |
| 1330 | callee.is_pure = true; |
| 1331 | let entry = callee.entry; |
| 1332 | let if_end = callee.create_block("if_end"); |
| 1333 | let if_then = callee.create_block("if_then"); |
| 1334 | let if_else = callee.create_block("if_else"); |
| 1335 | |
| 1336 | let shadow = push_inst( |
| 1337 | &mut callee, |
| 1338 | entry, |
| 1339 | InstKind::Alloca(IrType::Ptr(Box::new(IrType::Int(IntWidth::I32)))), |
| 1340 | IrType::Ptr(Box::new(IrType::Ptr(Box::new(IrType::Int(IntWidth::I32))))), |
| 1341 | ); |
| 1342 | push_inst( |
| 1343 | &mut callee, |
| 1344 | entry, |
| 1345 | InstKind::Store(ValueId(0), shadow), |
| 1346 | IrType::Void, |
| 1347 | ); |
| 1348 | let result = push_inst( |
| 1349 | &mut callee, |
| 1350 | entry, |
| 1351 | InstKind::Alloca(IrType::Int(IntWidth::I32)), |
| 1352 | IrType::Ptr(Box::new(IrType::Int(IntWidth::I32))), |
| 1353 | ); |
| 1354 | let p1 = push_inst( |
| 1355 | &mut callee, |
| 1356 | entry, |
| 1357 | InstKind::Load(shadow), |
| 1358 | IrType::Ptr(Box::new(IrType::Int(IntWidth::I32))), |
| 1359 | ); |
| 1360 | let n1 = push_inst( |
| 1361 | &mut callee, |
| 1362 | entry, |
| 1363 | InstKind::Load(p1), |
| 1364 | IrType::Int(IntWidth::I32), |
| 1365 | ); |
| 1366 | let one = push_inst( |
| 1367 | &mut callee, |
| 1368 | entry, |
| 1369 | InstKind::ConstInt(1, IntWidth::I32), |
| 1370 | IrType::Int(IntWidth::I32), |
| 1371 | ); |
| 1372 | let cond = push_inst( |
| 1373 | &mut callee, |
| 1374 | entry, |
| 1375 | InstKind::ICmp(CmpOp::Le, n1, one), |
| 1376 | IrType::Bool, |
| 1377 | ); |
| 1378 | callee.block_mut(entry).terminator = Some(Terminator::CondBranch { |
| 1379 | cond, |
| 1380 | true_dest: if_then, |
| 1381 | true_args: vec![], |
| 1382 | false_dest: if_else, |
| 1383 | false_args: vec![], |
| 1384 | }); |
| 1385 | |
| 1386 | let then_one = push_inst( |
| 1387 | &mut callee, |
| 1388 | if_then, |
| 1389 | InstKind::ConstInt(1, IntWidth::I32), |
| 1390 | IrType::Int(IntWidth::I32), |
| 1391 | ); |
| 1392 | push_inst( |
| 1393 | &mut callee, |
| 1394 | if_then, |
| 1395 | InstKind::Store(then_one, result), |
| 1396 | IrType::Void, |
| 1397 | ); |
| 1398 | callee.block_mut(if_then).terminator = Some(Terminator::Branch(if_end, vec![])); |
| 1399 | |
| 1400 | let p2 = push_inst( |
| 1401 | &mut callee, |
| 1402 | if_else, |
| 1403 | InstKind::Load(shadow), |
| 1404 | IrType::Ptr(Box::new(IrType::Int(IntWidth::I32))), |
| 1405 | ); |
| 1406 | let n2 = push_inst( |
| 1407 | &mut callee, |
| 1408 | if_else, |
| 1409 | InstKind::Load(p2), |
| 1410 | IrType::Int(IntWidth::I32), |
| 1411 | ); |
| 1412 | let p3 = push_inst( |
| 1413 | &mut callee, |
| 1414 | if_else, |
| 1415 | InstKind::Load(shadow), |
| 1416 | IrType::Ptr(Box::new(IrType::Int(IntWidth::I32))), |
| 1417 | ); |
| 1418 | let n3 = push_inst( |
| 1419 | &mut callee, |
| 1420 | if_else, |
| 1421 | InstKind::Load(p3), |
| 1422 | IrType::Int(IntWidth::I32), |
| 1423 | ); |
| 1424 | let one2 = push_inst( |
| 1425 | &mut callee, |
| 1426 | if_else, |
| 1427 | InstKind::ConstInt(1, IntWidth::I32), |
| 1428 | IrType::Int(IntWidth::I32), |
| 1429 | ); |
| 1430 | let dec1 = push_inst( |
| 1431 | &mut callee, |
| 1432 | if_else, |
| 1433 | InstKind::ISub(n3, one2), |
| 1434 | IrType::Int(IntWidth::I32), |
| 1435 | ); |
| 1436 | let p4 = push_inst( |
| 1437 | &mut callee, |
| 1438 | if_else, |
| 1439 | InstKind::Load(shadow), |
| 1440 | IrType::Ptr(Box::new(IrType::Int(IntWidth::I32))), |
| 1441 | ); |
| 1442 | let n4 = push_inst( |
| 1443 | &mut callee, |
| 1444 | if_else, |
| 1445 | InstKind::Load(p4), |
| 1446 | IrType::Int(IntWidth::I32), |
| 1447 | ); |
| 1448 | let one3 = push_inst( |
| 1449 | &mut callee, |
| 1450 | if_else, |
| 1451 | InstKind::ConstInt(1, IntWidth::I32), |
| 1452 | IrType::Int(IntWidth::I32), |
| 1453 | ); |
| 1454 | let dec2 = push_inst( |
| 1455 | &mut callee, |
| 1456 | if_else, |
| 1457 | InstKind::ISub(n4, one3), |
| 1458 | IrType::Int(IntWidth::I32), |
| 1459 | ); |
| 1460 | let wrap = push_inst( |
| 1461 | &mut callee, |
| 1462 | if_else, |
| 1463 | InstKind::Alloca(IrType::Int(IntWidth::I32)), |
| 1464 | IrType::Ptr(Box::new(IrType::Int(IntWidth::I32))), |
| 1465 | ); |
| 1466 | push_inst( |
| 1467 | &mut callee, |
| 1468 | if_else, |
| 1469 | InstKind::Store(dec2, wrap), |
| 1470 | IrType::Void, |
| 1471 | ); |
| 1472 | let rec = push_inst( |
| 1473 | &mut callee, |
| 1474 | if_else, |
| 1475 | InstKind::Call(FuncRef::Internal(0), vec![wrap]), |
| 1476 | IrType::Int(IntWidth::I32), |
| 1477 | ); |
| 1478 | let prod = push_inst( |
| 1479 | &mut callee, |
| 1480 | if_else, |
| 1481 | InstKind::IMul(n2, rec), |
| 1482 | IrType::Int(IntWidth::I32), |
| 1483 | ); |
| 1484 | push_inst( |
| 1485 | &mut callee, |
| 1486 | if_else, |
| 1487 | InstKind::Store(prod, result), |
| 1488 | IrType::Void, |
| 1489 | ); |
| 1490 | callee.block_mut(if_else).terminator = Some(Terminator::Branch(if_end, vec![])); |
| 1491 | |
| 1492 | let final_val = push_inst( |
| 1493 | &mut callee, |
| 1494 | if_end, |
| 1495 | InstKind::Load(result), |
| 1496 | IrType::Int(IntWidth::I32), |
| 1497 | ); |
| 1498 | callee.block_mut(if_end).terminator = Some(Terminator::Return(Some(final_val))); |
| 1499 | m.add_function(callee); |
| 1500 | |
| 1501 | let mut caller = Function::new("main".into(), vec![], IrType::Void); |
| 1502 | let caller_entry = caller.entry; |
| 1503 | let unit = push_inst( |
| 1504 | &mut caller, |
| 1505 | caller_entry, |
| 1506 | InstKind::ConstInt(6, IntWidth::I32), |
| 1507 | IrType::Int(IntWidth::I32), |
| 1508 | ); |
| 1509 | let unit2 = push_inst( |
| 1510 | &mut caller, |
| 1511 | caller_entry, |
| 1512 | InstKind::ConstInt(6, IntWidth::I32), |
| 1513 | IrType::Int(IntWidth::I32), |
| 1514 | ); |
| 1515 | let wrap1 = push_inst( |
| 1516 | &mut caller, |
| 1517 | caller_entry, |
| 1518 | InstKind::Alloca(IrType::Int(IntWidth::I32)), |
| 1519 | IrType::Ptr(Box::new(IrType::Int(IntWidth::I32))), |
| 1520 | ); |
| 1521 | push_inst( |
| 1522 | &mut caller, |
| 1523 | caller_entry, |
| 1524 | InstKind::Store(unit2, wrap1), |
| 1525 | IrType::Void, |
| 1526 | ); |
| 1527 | let call1 = push_inst( |
| 1528 | &mut caller, |
| 1529 | caller_entry, |
| 1530 | InstKind::Call(FuncRef::Internal(0), vec![wrap1]), |
| 1531 | IrType::Int(IntWidth::I32), |
| 1532 | ); |
| 1533 | let wrap2 = push_inst( |
| 1534 | &mut caller, |
| 1535 | caller_entry, |
| 1536 | InstKind::Alloca(IrType::Int(IntWidth::I32)), |
| 1537 | IrType::Ptr(Box::new(IrType::Int(IntWidth::I32))), |
| 1538 | ); |
| 1539 | push_inst( |
| 1540 | &mut caller, |
| 1541 | caller_entry, |
| 1542 | InstKind::Store(unit, wrap2), |
| 1543 | IrType::Void, |
| 1544 | ); |
| 1545 | let call2 = push_inst( |
| 1546 | &mut caller, |
| 1547 | caller_entry, |
| 1548 | InstKind::Call(FuncRef::Internal(0), vec![wrap2]), |
| 1549 | IrType::Int(IntWidth::I32), |
| 1550 | ); |
| 1551 | let sum = push_inst( |
| 1552 | &mut caller, |
| 1553 | caller_entry, |
| 1554 | InstKind::IAdd(call1, call2), |
| 1555 | IrType::Int(IntWidth::I32), |
| 1556 | ); |
| 1557 | caller.block_mut(caller_entry).terminator = Some(Terminator::Return(Some(sum))); |
| 1558 | m.add_function(caller); |
| 1559 | |
| 1560 | let pass = Gvn; |
| 1561 | assert!(pass.run(&mut m)); |
| 1562 | let caller = &m.functions[1]; |
| 1563 | let call_count = caller.blocks[0] |
| 1564 | .insts |
| 1565 | .iter() |
| 1566 | .filter(|inst| matches!(inst.kind, InstKind::Call(..))) |
| 1567 | .count(); |
| 1568 | assert_eq!( |
| 1569 | call_count, 1, |
| 1570 | "recursive PURE factorial calls should dedupe" |
| 1571 | ); |
| 1572 | } |
| 1573 | |
| 1574 | #[test] |
| 1575 | fn gvn_reuses_pure_calls_when_callee_follows_caller() { |
| 1576 | let mut m = Module::new("test".into()); |
| 1577 | |
| 1578 | let mut caller = Function::new("main".into(), vec![], IrType::Int(IntWidth::I32)); |
| 1579 | let entry = caller.entry; |
| 1580 | let c1 = push_inst( |
| 1581 | &mut caller, |
| 1582 | entry, |
| 1583 | InstKind::ConstInt(6, IntWidth::I32), |
| 1584 | IrType::Int(IntWidth::I32), |
| 1585 | ); |
| 1586 | let wrap1 = push_inst( |
| 1587 | &mut caller, |
| 1588 | entry, |
| 1589 | InstKind::Alloca(IrType::Int(IntWidth::I32)), |
| 1590 | IrType::Ptr(Box::new(IrType::Int(IntWidth::I32))), |
| 1591 | ); |
| 1592 | push_inst(&mut caller, entry, InstKind::Store(c1, wrap1), IrType::Void); |
| 1593 | let call1 = push_inst( |
| 1594 | &mut caller, |
| 1595 | entry, |
| 1596 | InstKind::Call(FuncRef::Internal(1), vec![wrap1]), |
| 1597 | IrType::Int(IntWidth::I32), |
| 1598 | ); |
| 1599 | let c2 = push_inst( |
| 1600 | &mut caller, |
| 1601 | entry, |
| 1602 | InstKind::ConstInt(6, IntWidth::I32), |
| 1603 | IrType::Int(IntWidth::I32), |
| 1604 | ); |
| 1605 | let wrap2 = push_inst( |
| 1606 | &mut caller, |
| 1607 | entry, |
| 1608 | InstKind::Alloca(IrType::Int(IntWidth::I32)), |
| 1609 | IrType::Ptr(Box::new(IrType::Int(IntWidth::I32))), |
| 1610 | ); |
| 1611 | push_inst(&mut caller, entry, InstKind::Store(c2, wrap2), IrType::Void); |
| 1612 | let call2 = push_inst( |
| 1613 | &mut caller, |
| 1614 | entry, |
| 1615 | InstKind::Call(FuncRef::Internal(1), vec![wrap2]), |
| 1616 | IrType::Int(IntWidth::I32), |
| 1617 | ); |
| 1618 | let sum = push_inst( |
| 1619 | &mut caller, |
| 1620 | entry, |
| 1621 | InstKind::IAdd(call1, call2), |
| 1622 | IrType::Int(IntWidth::I32), |
| 1623 | ); |
| 1624 | caller.block_mut(entry).terminator = Some(Terminator::Return(Some(sum))); |
| 1625 | m.add_function(caller); |
| 1626 | |
| 1627 | let param = Param { |
| 1628 | name: "n".into(), |
| 1629 | ty: IrType::Ptr(Box::new(IrType::Int(IntWidth::I32))), |
| 1630 | id: ValueId(0), |
| 1631 | fortran_noalias: false, |
| 1632 | }; |
| 1633 | let mut callee = |
| 1634 | Function::new("heavy_fact".into(), vec![param], IrType::Int(IntWidth::I32)); |
| 1635 | callee.is_pure = true; |
| 1636 | let callee_entry = callee.entry; |
| 1637 | let shadow = push_inst( |
| 1638 | &mut callee, |
| 1639 | callee_entry, |
| 1640 | InstKind::Alloca(IrType::Ptr(Box::new(IrType::Int(IntWidth::I32)))), |
| 1641 | IrType::Ptr(Box::new(IrType::Ptr(Box::new(IrType::Int(IntWidth::I32))))), |
| 1642 | ); |
| 1643 | push_inst( |
| 1644 | &mut callee, |
| 1645 | callee_entry, |
| 1646 | InstKind::Store(ValueId(0), shadow), |
| 1647 | IrType::Void, |
| 1648 | ); |
| 1649 | let arg_ptr = push_inst( |
| 1650 | &mut callee, |
| 1651 | callee_entry, |
| 1652 | InstKind::Load(shadow), |
| 1653 | IrType::Ptr(Box::new(IrType::Int(IntWidth::I32))), |
| 1654 | ); |
| 1655 | let arg_val = push_inst( |
| 1656 | &mut callee, |
| 1657 | callee_entry, |
| 1658 | InstKind::Load(arg_ptr), |
| 1659 | IrType::Int(IntWidth::I32), |
| 1660 | ); |
| 1661 | callee.block_mut(callee_entry).terminator = Some(Terminator::Return(Some(arg_val))); |
| 1662 | m.add_function(callee); |
| 1663 | |
| 1664 | let pass = Gvn; |
| 1665 | assert!(pass.run(&mut m)); |
| 1666 | let caller = &m.functions[0]; |
| 1667 | let call_count = caller.blocks[0] |
| 1668 | .insts |
| 1669 | .iter() |
| 1670 | .filter(|inst| matches!(inst.kind, InstKind::Call(..))) |
| 1671 | .count(); |
| 1672 | assert_eq!( |
| 1673 | call_count, 1, |
| 1674 | "caller-before-callee ordering should still dedupe" |
| 1675 | ); |
| 1676 | } |
| 1677 | |
| 1678 | #[test] |
| 1679 | fn gvn_matches_real_pure_recursive_fixture_after_pre_o2_passes() { |
| 1680 | let mut module = lower_fixture("pure_recursive_reuse.f90"); |
| 1681 | let pm = build_pre_gvn_o2_pipeline(); |
| 1682 | pm.run(&mut module); |
| 1683 | |
| 1684 | let pure_calls: Vec<PureCallPolicy> = module |
| 1685 | .functions |
| 1686 | .iter() |
| 1687 | .map(PureCallPolicy::for_function) |
| 1688 | .collect(); |
| 1689 | assert!( |
| 1690 | pure_calls.iter().any(|policy| policy.reusable), |
| 1691 | "at least one function in the fixture should remain a reusable PURE callee:\n{}", |
| 1692 | crate::ir::printer::print_module(&module) |
| 1693 | ); |
| 1694 | |
| 1695 | let caller_idx = module |
| 1696 | .functions |
| 1697 | .iter() |
| 1698 | .position(|func| func.name == "__prog_pure_recursive_reuse") |
| 1699 | .expect("program entry in fixture"); |
| 1700 | let wrappers = wrapper_alloca_values(&module.functions[caller_idx], &pure_calls); |
| 1701 | assert!( |
| 1702 | !wrappers.is_empty(), |
| 1703 | "caller should still expose scalar by-ref wrapper allocas before GVN" |
| 1704 | ); |
| 1705 | |
| 1706 | let pass = Gvn; |
| 1707 | assert!( |
| 1708 | pass.run(&mut module), |
| 1709 | "GVN should make progress on the real fixture" |
| 1710 | ); |
| 1711 | |
| 1712 | let caller = &module.functions[caller_idx]; |
| 1713 | let call_count = caller.blocks[0] |
| 1714 | .insts |
| 1715 | .iter() |
| 1716 | .filter(|inst| matches!(inst.kind, InstKind::Call(FuncRef::Internal(_), _))) |
| 1717 | .count(); |
| 1718 | assert_eq!( |
| 1719 | call_count, 1, |
| 1720 | "real fixture caller should end with one PURE recursive call" |
| 1721 | ); |
| 1722 | } |
| 1723 | |
| 1724 | #[test] |
| 1725 | fn gvn_does_not_reuse_pure_calls_with_pointer_args() { |
| 1726 | let mut m = Module::new("test".into()); |
| 1727 | |
| 1728 | let param = Param { |
| 1729 | name: "p".into(), |
| 1730 | ty: IrType::Ptr(Box::new(IrType::Int(IntWidth::I32))), |
| 1731 | id: ValueId(0), |
| 1732 | fortran_noalias: false, |
| 1733 | }; |
| 1734 | let mut callee = Function::new("peek".into(), vec![param], IrType::Int(IntWidth::I32)); |
| 1735 | callee.is_pure = true; |
| 1736 | let callee_entry = callee.entry; |
| 1737 | let zero = push_inst( |
| 1738 | &mut callee, |
| 1739 | callee_entry, |
| 1740 | InstKind::ConstInt(0, IntWidth::I32), |
| 1741 | IrType::Int(IntWidth::I32), |
| 1742 | ); |
| 1743 | callee.block_mut(callee_entry).terminator = Some(Terminator::Return(Some(zero))); |
| 1744 | m.add_function(callee); |
| 1745 | |
| 1746 | let mut caller = Function::new("main".into(), vec![], IrType::Int(IntWidth::I32)); |
| 1747 | let entry = caller.entry; |
| 1748 | let slot = push_inst( |
| 1749 | &mut caller, |
| 1750 | entry, |
| 1751 | InstKind::Alloca(IrType::Int(IntWidth::I32)), |
| 1752 | IrType::Ptr(Box::new(IrType::Int(IntWidth::I32))), |
| 1753 | ); |
| 1754 | let call1 = push_inst( |
| 1755 | &mut caller, |
| 1756 | entry, |
| 1757 | InstKind::Call(FuncRef::Internal(0), vec![slot]), |
| 1758 | IrType::Int(IntWidth::I32), |
| 1759 | ); |
| 1760 | let call2 = push_inst( |
| 1761 | &mut caller, |
| 1762 | entry, |
| 1763 | InstKind::Call(FuncRef::Internal(0), vec![slot]), |
| 1764 | IrType::Int(IntWidth::I32), |
| 1765 | ); |
| 1766 | let sum = push_inst( |
| 1767 | &mut caller, |
| 1768 | entry, |
| 1769 | InstKind::IAdd(call1, call2), |
| 1770 | IrType::Int(IntWidth::I32), |
| 1771 | ); |
| 1772 | caller.block_mut(entry).terminator = Some(Terminator::Return(Some(sum))); |
| 1773 | m.add_function(caller); |
| 1774 | |
| 1775 | let pass = Gvn; |
| 1776 | assert!( |
| 1777 | !pass.run(&mut m), |
| 1778 | "pointer-arg PURE calls must stay distinct" |
| 1779 | ); |
| 1780 | |
| 1781 | let caller = &m.functions[1]; |
| 1782 | let call_count = caller.blocks[0] |
| 1783 | .insts |
| 1784 | .iter() |
| 1785 | .filter(|inst| matches!(inst.kind, InstKind::Call(..))) |
| 1786 | .count(); |
| 1787 | assert_eq!(call_count, 2); |
| 1788 | } |
| 1789 | } |
| 1790 |