Author: nihui Date: 2024-04-29T13:18:37+01:00 New Revision: cb3174bd7895535d2f397695b5b20b1e90876997
URL: https://github.com/llvm/llvm-project/commit/cb3174bd7895535d2f397695b5b20b1e90876997 DIFF: https://github.com/llvm/llvm-project/commit/cb3174bd7895535d2f397695b5b20b1e90876997.diff LOG: [clang][CodeGen] fix UB in aarch64 bfloat16 scalar conversion (#89062) do not bitcast 16bit `bfloat16` to 32bit `int32_t` directly bitcast to `int16_t`, and then upcast to `int32_t` Fix ASAN runtime error when calling vcvtah_f32_bf16 `==21842==ERROR: AddressSanitizer: stack-buffer-overflow on address 0x007fda1dd063 at pc 0x005c0361c234 bp 0x007fda1dd030 sp 0x007fda1dd028 ` without patch ```c __ai __attribute__((target("bf16"))) float32_t vcvtah_f32_bf16(bfloat16_t __p0) { float32_t __ret; bfloat16_t __reint = __p0; int32_t __reint1 = *(int32_t *) &__reint << 16; __ret = *(float32_t *) &__reint1; return __ret; } ``` with this patch ```c __ai __attribute__((target("bf16"))) float32_t vcvtah_f32_bf16(bfloat16_t __p0) { float32_t __ret; bfloat16_t __reint = __p0; int32_t __reint1 = (int32_t)(*(int16_t *) &__reint) << 16; __ret = *(float32_t *) &__reint1; return __ret; } ``` fix issue https://github.com/llvm/llvm-project/issues/61983 Added: Modified: clang/include/clang/Basic/arm_neon.td clang/test/CodeGen/arm-bf16-convert-intrinsics.c Removed: ################################################################################ diff --git a/clang/include/clang/Basic/arm_neon.td b/clang/include/clang/Basic/arm_neon.td index 6d655c39360d3b..6390ba3f9fe5e5 100644 --- a/clang/include/clang/Basic/arm_neon.td +++ b/clang/include/clang/Basic/arm_neon.td @@ -275,7 +275,7 @@ def OP_VCVT_BF16_F32_HI_A32 (call "vget_low", $p0))>; def OP_CVT_F32_BF16 - : Op<(bitcast "R", (op "<<", (bitcast "int32_t", $p0), + : Op<(bitcast "R", (op "<<", (cast "int32_t", (bitcast "int16_t", $p0)), (literal "int32_t", "16")))>; //===----------------------------------------------------------------------===// diff --git a/clang/test/CodeGen/arm-bf16-convert-intrinsics.c b/clang/test/CodeGen/arm-bf16-convert-intrinsics.c index f50eaf371028cd..0f2c5b2546fa35 100644 --- a/clang/test/CodeGen/arm-bf16-convert-intrinsics.c +++ b/clang/test/CodeGen/arm-bf16-convert-intrinsics.c @@ -426,11 +426,12 @@ bfloat16_t test_vcvth_bf16_f32(float32_t a) { // CHECK-NEXT: [[__REINT_I:%.*]] = alloca bfloat, align 2 // CHECK-NEXT: [[__REINT1_I:%.*]] = alloca i32, align 4 // CHECK-NEXT: store bfloat [[A:%.*]], ptr [[__REINT_I]], align 2 -// CHECK-NEXT: [[TMP1:%.*]] = load i32, ptr [[__REINT_I]], align 2 -// CHECK-NEXT: [[SHL_I:%.*]] = shl i32 [[TMP1]], 16 +// CHECK-NEXT: [[TMP0:%.*]] = load i16, ptr [[__REINT_I]], align 2 +// CHECK-NEXT: [[CONV_I:%.*]] = sext i16 [[TMP0]] to i32 +// CHECK-NEXT: [[SHL_I:%.*]] = shl i32 [[CONV_I]], 16 // CHECK-NEXT: store i32 [[SHL_I]], ptr [[__REINT1_I]], align 4 -// CHECK-NEXT: [[TMP3:%.*]] = load float, ptr [[__REINT1_I]], align 4 -// CHECK-NEXT: ret float [[TMP3]] +// CHECK-NEXT: [[TMP1:%.*]] = load float, ptr [[__REINT1_I]], align 4 +// CHECK-NEXT: ret float [[TMP1]] // float32_t test_vcvtah_f32_bf16(bfloat16_t a) { return vcvtah_f32_bf16(a); _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits