https://github.com/steffenlarsen created https://github.com/llvm/llvm-project/pull/220874
This commit fixes the preservation of volatile semantics for atomic RMW operations in CIR CodeGen. >From 316c08a6875f784518ae3afa52450d8e0ff75deb Mon Sep 17 00:00:00 2001 From: Steffen Holst Larsen <[email protected]> Date: Thu, 3 Sep 2026 06:03:08 -0500 Subject: [PATCH] [CIR] Preserve volatile semantics for atomic operations This commit fixes the preservation of volatile semantics for atomic RMW operations in CIR CodeGen. Signed-off-by: Steffen Holst Larsen <[email protected]> --- .../CIR/Lowering/DirectToLLVM/LowerToLLVM.cpp | 4 +-- clang/test/CIR/CodeGen/atomic-scoped.c | 13 +++++++++ clang/test/CIR/CodeGen/atomic.c | 28 +++++++++++++++++++ 3 files changed, 43 insertions(+), 2 deletions(-) diff --git a/clang/lib/CIR/Lowering/DirectToLLVM/LowerToLLVM.cpp b/clang/lib/CIR/Lowering/DirectToLLVM/LowerToLLVM.cpp index 233e6aaa15adb..1cea870626de1 100644 --- a/clang/lib/CIR/Lowering/DirectToLLVM/LowerToLLVM.cpp +++ b/clang/lib/CIR/Lowering/DirectToLLVM/LowerToLLVM.cpp @@ -1230,7 +1230,7 @@ mlir::LogicalResult CIRToLLVMAtomicXchgOpLowering::matchAndRewrite( llvm::StringRef llvmSyncScope = getLLVMSyncScope(adaptor.getSyncScope()); rewriter.replaceOpWithNewOp<mlir::LLVM::AtomicRMWOp>( op, mlir::LLVM::AtomicBinOp::xchg, adaptor.getPtr(), adaptor.getVal(), - llvmOrder, llvmSyncScope); + llvmOrder, llvmSyncScope, /*alignment=*/0, op.getIsVolatile()); return mlir::success(); } @@ -1428,7 +1428,7 @@ mlir::LogicalResult CIRToLLVMAtomicFetchOpLowering::matchAndRewrite( getLLVMAtomicBinOp(op.getBinop(), isInt, isSignedInt); auto rmwVal = mlir::LLVM::AtomicRMWOp::create( rewriter, op.getLoc(), llvmBinOp, adaptor.getPtr(), adaptor.getVal(), - llvmOrder, llvmSyncScope); + llvmOrder, llvmSyncScope, /*alignment=*/0, op.getIsVolatile()); mlir::Value result = rmwVal.getResult(); if (!op.getFetchFirst()) { diff --git a/clang/test/CIR/CodeGen/atomic-scoped.c b/clang/test/CIR/CodeGen/atomic-scoped.c index 991f19bcbbd7c..aa7571d83cdc5 100644 --- a/clang/test/CIR/CodeGen/atomic-scoped.c +++ b/clang/test/CIR/CodeGen/atomic-scoped.c @@ -119,6 +119,19 @@ void scoped_atomic_exchange_n(int *ptr, int value) { // OGCG: %{{.+}} = atomicrmw xchg ptr %{{.+}}, i32 %{{.+}} monotonic, align 4 } +void scoped_atomic_exchange_n_volatile(volatile int *ptr, int value) { + // CIR-BEFORE-TL-LABEL: @scoped_atomic_exchange_n_volatile + // CIR-LABEL: @scoped_atomic_exchange_n_volatile + // LLVM-LABEL: @scoped_atomic_exchange_n_volatile + // OGCG-LABEL: @scoped_atomic_exchange_n_volatile + + __scoped_atomic_exchange_n(ptr, value, __ATOMIC_RELAXED, __MEMORY_SCOPE_SYSTEM); + // CIR-BEFORE-TL: cir.atomic.xchg relaxed syncscope(system) volatile %{{.+}}, %{{.+}} : (!cir.ptr<!s32i>, !s32i) -> !s32i + // CIR: %{{.+}} = cir.atomic.xchg relaxed syncscope(system) volatile %{{.+}}, %{{.+}} : (!cir.ptr<!s32i>, !s32i) -> !s32i + // LLVM: %{{.+}} = atomicrmw volatile xchg ptr %{{.+}}, i32 %{{.+}} monotonic, align 4 + // OGCG: %{{.+}} = atomicrmw volatile xchg ptr %{{.+}}, i32 %{{.+}} monotonic, align 4 +} + void scoped_atomic_cmpxchg(int *ptr, int *expected, int *desired) { // CIR-BEFORE-TL-LABEL: @scoped_atomic_cmpxchg // CIR-LABEL: @scoped_atomic_cmpxchg diff --git a/clang/test/CIR/CodeGen/atomic.c b/clang/test/CIR/CodeGen/atomic.c index 96a84eeac4929..21b99331fb417 100644 --- a/clang/test/CIR/CodeGen/atomic.c +++ b/clang/test/CIR/CodeGen/atomic.c @@ -929,6 +929,19 @@ void atomic_exchange_n(int *ptr, int value) { // OGCG: %{{.+}} = atomicrmw xchg ptr %{{.+}}, i32 %{{.+}} seq_cst, align 4 } +int atomic_exchange_n_volatile(volatile int *ptr, int value) { + // CIR-LABEL: @atomic_exchange_n_volatile + // LLVM-LABEL: @atomic_exchange_n_volatile + // OGCG-LABEL: @atomic_exchange_n_volatile + + return __atomic_exchange_n(ptr, value, __ATOMIC_SEQ_CST); + // CIR: %{{.+}} = cir.atomic.xchg seq_cst syncscope(system) volatile %{{.+}}, %{{.+}} : (!cir.ptr<!s32i>, !s32i) -> !s32i + + // LLVM: %{{.+}} = atomicrmw volatile xchg ptr %{{.+}}, i32 %{{.+}} seq_cst, align 4 + + // OGCG: %{{.+}} = atomicrmw volatile xchg ptr %{{.+}}, i32 %{{.+}} seq_cst, align 4 +} + void test_and_set(void *p) { // CIR-LABEL: @test_and_set // LLVM-LABEL: @test_and_set @@ -1057,6 +1070,21 @@ int atomic_fetch_add(int *ptr, int value) { // OGCG-NEXT: store i32 %[[RES]], ptr %{{.+}}, align 4 } +int atomic_fetch_add_volatile(volatile int *ptr, int value) { + // CIR-LABEL: @atomic_fetch_add_volatile + // LLVM-LABEL: @atomic_fetch_add_volatile + // OGCG-LABEL: @atomic_fetch_add_volatile + + return __atomic_fetch_add(ptr, value, __ATOMIC_SEQ_CST); + // CIR: %{{.+}} = cir.atomic.fetch add seq_cst syncscope(system) fetch_first %{{.+}}, %{{.+}} volatile : (!cir.ptr<!s32i>, !s32i) -> !s32i + + // LLVM: %[[RES:.+]] = atomicrmw volatile add ptr %{{.+}}, i32 %{{.+}} seq_cst, align 4 + // LLVM-NEXT: store i32 %[[RES]], ptr %{{.+}}, align 4 + + // OGCG: %[[RES:.+]] = atomicrmw volatile add ptr %{{.+}}, i32 %{{.+}} seq_cst, align 4 + // OGCG-NEXT: store i32 %[[RES]], ptr %{{.+}}, align 4 +} + int *atomic_fetch_add_ptr(int **ptr, __PTRDIFF_TYPE__ value) { // CIR-LABEL: @atomic_fetch_add_ptr // LLVM-LABEL: @atomic_fetch_add_ptr _______________________________________________ cfe-commits mailing list [email protected] https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
