Author: Kiran Date: 2026-02-06T09:41:57Z New Revision: 4af27b06f517cec52b14e72a30a8a9185b662086
URL: https://github.com/llvm/llvm-project/commit/4af27b06f517cec52b14e72a30a8a9185b662086 DIFF: https://github.com/llvm/llvm-project/commit/4af27b06f517cec52b14e72a30a8a9185b662086.diff LOG: [Clang] Fix atomic boolean compound assignment (#178220) Fixes #33210 Added: clang/test/CodeGen/compound-assign-atomic-bool.c Modified: clang/docs/ReleaseNotes.rst clang/lib/CodeGen/CGExprScalar.cpp Removed: ################################################################################ diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst index 24d4e07ca68b3..1f925419432bb 100644 --- a/clang/docs/ReleaseNotes.rst +++ b/clang/docs/ReleaseNotes.rst @@ -223,6 +223,9 @@ Improvements to Coverage Mapping Bug Fixes in This Version ------------------------- + +- Fixed atomic boolean compound assignment; the conversion back to atomic bool would be miscompiled. (#GH33210) + - Fixed a failed assertion in the preprocessor when ``__has_embed`` parameters are missing parentheses. (#GH175088) - Fix lifetime extension of temporaries in for-range-initializers in templates. (#GH165182) diff --git a/clang/lib/CodeGen/CGExprScalar.cpp b/clang/lib/CodeGen/CGExprScalar.cpp index d21e017bd2b56..1f9389660e127 100644 --- a/clang/lib/CodeGen/CGExprScalar.cpp +++ b/clang/lib/CodeGen/CGExprScalar.cpp @@ -4035,9 +4035,14 @@ LValue ScalarExprEmitter::EmitCompoundAssignLValue( if (LHSLV.isBitField()) { Previous = Result; Result = EmitScalarConversion(Result, PromotionTypeCR, LHSTy, Loc); - } else + } else if (const auto *atomicTy = LHSTy->getAs<AtomicType>()) { + Result = + EmitScalarConversion(Result, PromotionTypeCR, atomicTy->getValueType(), + Loc, ScalarConversionOpts(CGF.SanOpts)); + } else { Result = EmitScalarConversion(Result, PromotionTypeCR, LHSTy, Loc, ScalarConversionOpts(CGF.SanOpts)); + } if (atomicPHI) { llvm::BasicBlock *curBlock = Builder.GetInsertBlock(); diff --git a/clang/test/CodeGen/compound-assign-atomic-bool.c b/clang/test/CodeGen/compound-assign-atomic-bool.c new file mode 100644 index 0000000000000..4e8f351b49b81 --- /dev/null +++ b/clang/test/CodeGen/compound-assign-atomic-bool.c @@ -0,0 +1,29 @@ +// RUN: %clang_cc1 -emit-llvm -o - %s | FileCheck %s + +// When performing compound assignment on atomic_bool, ensure that we +// correctly handle the conversion from integer to boolean, by comparing +// with zero rather than truncating. + +// CHECK: @compund_assign_add +int compund_assign_add(void) { + _Atomic _Bool b; + + b += 2; + // CHECK: add + // CHECK-NEXT: icmp ne + // CHECK-NEXT: zext + // CHECK-NEXT: cmpxchg + return b; +} + +// CHECK: @compund_assign_minus +int compund_assign_minus(void) { + _Atomic _Bool b; + + b -= 2; + // CHECK: sub + // CHECK-NEXT: icmp ne + // CHECK-NEXT: zext + // CHECK-NEXT: cmpxchg + return b; +} _______________________________________________ cfe-commits mailing list [email protected] https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
