Index: lib/Transforms/Scalar/MergeICmps.cpp =================================================================== --- lib/Transforms/Scalar/MergeICmps.cpp +++ lib/Transforms/Scalar/MergeICmps.cpp @@ -81,8 +81,9 @@ LLVM_DEBUG(dbgs() << "used outside of block\n"); return {}; } - if (LoadI->isVolatile()) { - LLVM_DEBUG(dbgs() << "volatile\n"); + // Do not optimize atomic loads to non-atomic memcmp + if (!LoadI->isSimple()) { + LLVM_DEBUG(dbgs() << "volatile or atomic\n"); return {}; } Value *const Addr = LoadI->getOperand(0); Index: test/Transforms/MergeICmps/X86/atomic.ll =================================================================== --- /dev/null +++ test/Transforms/MergeICmps/X86/atomic.ll @@ -0,0 +1,47 @@ +; NOTE: Assertions have been autogenerated by utils/update_test_checks.py +; RUN: opt < %s -mergeicmps -mtriple=x86_64-unknown-unknown -S | FileCheck %s + +%"struct.std::pair" = type { i32, i32 } + +define zeroext i1 @opeq( +; CHECK-LABEL: @opeq( +; CHECK-NEXT: entry: +; CHECK-NEXT: [[FIRST_I:%.*]] = getelementptr inbounds %"struct.std::pair", %"struct.std::pair"* [[A:%.*]], i64 0, i32 0 +; CHECK-NEXT: [[TMP0:%.*]] = load i32, i32* [[FIRST_I]], align 4 +; CHECK-NEXT: [[FIRST1_I:%.*]] = getelementptr inbounds %"struct.std::pair", %"struct.std::pair"* [[B:%.*]], i64 0, i32 0 +; CHECK-NEXT: [[TMP1:%.*]] = load i32, i32* [[FIRST1_I]], align 4 +; CHECK-NEXT: [[CMP_I:%.*]] = icmp eq i32 [[TMP0]], [[TMP1]] +; CHECK-NEXT: br i1 [[CMP_I]], label [[LAND_RHS_I:%.*]], label [[OPEQ1_EXIT:%.*]] +; CHECK: land.rhs.i: +; CHECK-NEXT: [[SECOND_I:%.*]] = getelementptr inbounds %"struct.std::pair", %"struct.std::pair"* [[A]], i64 0, i32 1 +; CHECK-NEXT: [[TMP2:%.*]] = load atomic i32, i32* [[SECOND_I]] seq_cst, align 4 +; CHECK-NEXT: [[SECOND2_I:%.*]] = getelementptr inbounds %"struct.std::pair", %"struct.std::pair"* [[B]], i64 0, i32 1 +; CHECK-NEXT: [[TMP3:%.*]] = load i32, i32* [[SECOND2_I]], align 4 +; CHECK-NEXT: [[CMP3_I:%.*]] = icmp eq i32 [[TMP2]], [[TMP3]] +; CHECK-NEXT: br label [[OPEQ1_EXIT]] +; CHECK: opeq1.exit: +; CHECK-NEXT: [[TMP4:%.*]] = phi i1 [ false, [[ENTRY:%.*]] ], [ [[CMP3_I]], [[LAND_RHS_I]] ] +; CHECK-NEXT: ret i1 [[TMP4]] +; + %"struct.std::pair"* nocapture readonly dereferenceable(8) %a, + %"struct.std::pair"* nocapture readonly dereferenceable(8) %b) local_unnamed_addr #0 { +entry: + %first.i = getelementptr inbounds %"struct.std::pair", %"struct.std::pair"* %a, i64 0, i32 0 + %0 = load i32, i32* %first.i, align 4 + %first1.i = getelementptr inbounds %"struct.std::pair", %"struct.std::pair"* %b, i64 0, i32 0 + %1 = load i32, i32* %first1.i, align 4 + %cmp.i = icmp eq i32 %0, %1 + br i1 %cmp.i, label %land.rhs.i, label %opeq1.exit + +land.rhs.i: + %second.i = getelementptr inbounds %"struct.std::pair", %"struct.std::pair"* %a, i64 0, i32 1 + %2 = load atomic i32, i32* %second.i seq_cst, align 4 + %second2.i = getelementptr inbounds %"struct.std::pair", %"struct.std::pair"* %b, i64 0, i32 1 + %3 = load i32, i32* %second2.i, align 4 + %cmp3.i = icmp eq i32 %2, %3 + br label %opeq1.exit + +opeq1.exit: + %4 = phi i1 [ false, %entry ], [ %cmp3.i, %land.rhs.i ] + ret i1 %4 +}