Author: Nikita Popov Date: 2022-04-08T15:18:12+02:00 New Revision: 692a147bf4339380ccfea7418cbedcea540cfaef
URL: https://github.com/llvm/llvm-project/commit/692a147bf4339380ccfea7418cbedcea540cfaef DIFF: https://github.com/llvm/llvm-project/commit/692a147bf4339380ccfea7418cbedcea540cfaef.diff LOG: [CGCall] Make findDominatingStoreToReturnValue() more robust This was skipping specific lifetime + bitcast patterns, but with opaque pointers the bitcast will not be present, and we did not perform this fold. Instead skip over lifetime.end and bitcasts generally, without trying to correlate them. Added: clang/test/CodeGen/dominating-store-to-return.c Modified: clang/lib/CodeGen/CGCall.cpp Removed: ################################################################################ diff --git a/clang/lib/CodeGen/CGCall.cpp b/clang/lib/CodeGen/CGCall.cpp index e2ffd57dcbd0e..c4d342e3d2aaa 100644 --- a/clang/lib/CodeGen/CGCall.cpp +++ b/clang/lib/CodeGen/CGCall.cpp @@ -3242,28 +3242,19 @@ static llvm::StoreInst *findDominatingStoreToReturnValue(CodeGenFunction &CGF) { if (!CGF.ReturnValue.getPointer()->hasOneUse()) { llvm::BasicBlock *IP = CGF.Builder.GetInsertBlock(); if (IP->empty()) return nullptr; - llvm::Instruction *I = &IP->back(); - - // Skip lifetime markers - for (llvm::BasicBlock::reverse_iterator II = IP->rbegin(), - IE = IP->rend(); - II != IE; ++II) { - if (llvm::IntrinsicInst *Intrinsic = - dyn_cast<llvm::IntrinsicInst>(&*II)) { - if (Intrinsic->getIntrinsicID() == llvm::Intrinsic::lifetime_end) { - const llvm::Value *CastAddr = Intrinsic->getArgOperand(1); - ++II; - if (II == IE) - break; - if (isa<llvm::BitCastInst>(&*II) && (CastAddr == &*II)) - continue; - } - } - I = &*II; - break; - } - return GetStoreIfValid(I); + // Look at directly preceding instruction, skipping bitcasts and lifetime + // markers. + for (llvm::Instruction &I : make_range(IP->rbegin(), IP->rend())) { + if (isa<llvm::BitCastInst>(&I)) + continue; + if (auto *II = dyn_cast<llvm::IntrinsicInst>(&I)) + if (II->getIntrinsicID() == llvm::Intrinsic::lifetime_end) + continue; + + return GetStoreIfValid(&I); + } + return nullptr; } llvm::StoreInst *store = diff --git a/clang/test/CodeGen/dominating-store-to-return.c b/clang/test/CodeGen/dominating-store-to-return.c new file mode 100644 index 0000000000000..42595c5296098 --- /dev/null +++ b/clang/test/CodeGen/dominating-store-to-return.c @@ -0,0 +1,28 @@ +// NOTE: Assertions have been autogenerated by utils/update_cc_test_checks.py +// RUN: %clang_cc1 -opaque-pointers -triple x86_64-unknown-unknown -emit-llvm %s -o - | FileCheck %s --check-prefix=NO-LIFETIME +// RUN: %clang_cc1 -opaque-pointers -O1 -disable-llvm-optzns -triple x86_64-unknown-unknown -emit-llvm %s -o - | FileCheck %s --check-prefix=LIFETIME + +// NO-LIFETIME-LABEL: @main( +// NO-LIFETIME-NEXT: entry: +// NO-LIFETIME-NEXT: [[RETVAL:%.*]] = alloca i32, align 4 +// NO-LIFETIME-NEXT: [[FOO:%.*]] = alloca i32, align 4 +// NO-LIFETIME-NEXT: [[FOO2:%.*]] = alloca i32, align 4 +// NO-LIFETIME-NEXT: store i32 0, ptr [[RETVAL]], align 4 +// NO-LIFETIME-NEXT: ret i32 0 +// +// LIFETIME-LABEL: @main( +// LIFETIME-NEXT: entry: +// LIFETIME-NEXT: [[RETVAL:%.*]] = alloca i32, align 4 +// LIFETIME-NEXT: [[FOO:%.*]] = alloca i32, align 4 +// LIFETIME-NEXT: [[FOO2:%.*]] = alloca i32, align 4 +// LIFETIME-NEXT: store i32 0, ptr [[RETVAL]], align 4 +// LIFETIME-NEXT: call void @llvm.lifetime.start.p0(i64 4, ptr [[FOO]]) #[[ATTR2:[0-9]+]] +// LIFETIME-NEXT: call void @llvm.lifetime.start.p0(i64 4, ptr [[FOO2]]) #[[ATTR2]] +// LIFETIME-NEXT: call void @llvm.lifetime.end.p0(i64 4, ptr [[FOO2]]) #[[ATTR2]] +// LIFETIME-NEXT: call void @llvm.lifetime.end.p0(i64 4, ptr [[FOO]]) #[[ATTR2]] +// LIFETIME-NEXT: ret i32 0 +// +int main() { + unsigned foo, foo2; + return 0; +} _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
