diff options
| -rw-r--r-- | llvm/lib/Transforms/Utils/Local.cpp | 77 |
1 files changed, 38 insertions, 39 deletions
diff --git a/llvm/lib/Transforms/Utils/Local.cpp b/llvm/lib/Transforms/Utils/Local.cpp index 86876f7b2c6..a0e79b68e72 100644 --- a/llvm/lib/Transforms/Utils/Local.cpp +++ b/llvm/lib/Transforms/Utils/Local.cpp @@ -2016,43 +2016,43 @@ static bool markAliveBlocks(Function &F, // instructions into LLVM unreachable insts. The instruction combining pass // canonicalizes unreachable insts into stores to null or undef. for (Instruction &I : *BB) { - // Assumptions that are known to be false are equivalent to unreachable. - // Also, if the condition is undefined, then we make the choice most - // beneficial to the optimizer, and choose that to also be unreachable. - if (auto *II = dyn_cast<IntrinsicInst>(&I)) { - if (II->getIntrinsicID() == Intrinsic::assume) { - if (match(II->getArgOperand(0), m_CombineOr(m_Zero(), m_Undef()))) { - // Don't insert a call to llvm.trap right before the unreachable. - changeToUnreachable(II, false, false, DDT); - Changed = true; - break; - } - } - - if (II->getIntrinsicID() == Intrinsic::experimental_guard) { - // A call to the guard intrinsic bails out of the current compilation - // unit if the predicate passed to it is false. If the predicate is a - // constant false, then we know the guard will bail out of the current - // compile unconditionally, so all code following it is dead. - // - // Note: unlike in llvm.assume, it is not "obviously profitable" for - // guards to treat `undef` as `false` since a guard on `undef` can - // still be useful for widening. - if (match(II->getArgOperand(0), m_Zero())) - if (!isa<UnreachableInst>(II->getNextNode())) { - changeToUnreachable(II->getNextNode(), /*UseLLVMTrap=*/false, - false, DDT); + if (auto *CI = dyn_cast<CallInst>(&I)) { + Value *Callee = CI->getCalledValue(); + // Handle intrinsic calls. + if (Function *F = dyn_cast<Function>(Callee)) { + auto IntrinsicID = F->getIntrinsicID(); + // Assumptions that are known to be false are equivalent to + // unreachable. Also, if the condition is undefined, then we make the + // choice most beneficial to the optimizer, and choose that to also be + // unreachable. + if (IntrinsicID == Intrinsic::assume) { + if (match(CI->getArgOperand(0), m_CombineOr(m_Zero(), m_Undef()))) { + // Don't insert a call to llvm.trap right before the unreachable. + changeToUnreachable(CI, false, false, DDT); Changed = true; break; } - } - } - - if (auto *CI = dyn_cast<CallInst>(&I)) { - Value *Callee = CI->getCalledValue(); - if ((isa<ConstantPointerNull>(Callee) && - !NullPointerIsDefined(CI->getFunction())) || - isa<UndefValue>(Callee)) { + } else if (IntrinsicID == Intrinsic::experimental_guard) { + // A call to the guard intrinsic bails out of the current + // compilation unit if the predicate passed to it is false. If the + // predicate is a constant false, then we know the guard will bail + // out of the current compile unconditionally, so all code following + // it is dead. + // + // Note: unlike in llvm.assume, it is not "obviously profitable" for + // guards to treat `undef` as `false` since a guard on `undef` can + // still be useful for widening. + if (match(CI->getArgOperand(0), m_Zero())) + if (!isa<UnreachableInst>(CI->getNextNode())) { + changeToUnreachable(CI->getNextNode(), /*UseLLVMTrap=*/false, + false, DDT); + Changed = true; + break; + } + } + } else if ((isa<ConstantPointerNull>(Callee) && + !NullPointerIsDefined(CI->getFunction())) || + isa<UndefValue>(Callee)) { changeToUnreachable(CI, /*UseLLVMTrap=*/false, false, DDT); Changed = true; break; @@ -2068,12 +2068,11 @@ static bool markAliveBlocks(Function &F, } break; } - } + } else if (auto *SI = dyn_cast<StoreInst>(&I)) { + // Store to undef and store to null are undefined and used to signal + // that they should be changed to unreachable by passes that can't + // modify the CFG. - // Store to undef and store to null are undefined and used to signal that - // they should be changed to unreachable by passes that can't modify the - // CFG. - if (auto *SI = dyn_cast<StoreInst>(&I)) { // Don't touch volatile stores. if (SI->isVolatile()) continue; |
