From 9d8e9ff6206347ae56f242daf17d08160a184b2e Mon Sep 17 00:00:00 2001 From: Craig Topper Date: Sat, 5 Aug 2017 23:35:54 +0000 Subject: [PATCH] [X86] Enable isel to use the PAUSE instruction even when SSE2 is disabled. Clang part Summary: On older processors this instruction encoding is treated as a NOP. MSVC doesn't disable intrinsics based on features the way clang/gcc does. Because the PAUSE instruction encoding doesn't crash older processors, some software out there uses these intrinsics without checking for SSE2. This change also seems to also be consistent with gcc behavior. Fixes PR34079 Reviewers: RKSimon, zvi Reviewed By: RKSimon Subscribers: cfe-commits Differential Revision: https://reviews.llvm.org/D36362 llvm-svn: 310191 --- clang/include/clang/Basic/BuiltinsX86.def | 4 ++-- clang/test/CodeGen/pause.c | 11 +++++++++++ 2 files changed, 13 insertions(+), 2 deletions(-) create mode 100644 clang/test/CodeGen/pause.c diff --git a/clang/include/clang/Basic/BuiltinsX86.def b/clang/include/clang/Basic/BuiltinsX86.def index a516bf6..6d3a478 100644 --- a/clang/include/clang/Basic/BuiltinsX86.def +++ b/clang/include/clang/Basic/BuiltinsX86.def @@ -338,8 +338,8 @@ TARGET_BUILTIN(__builtin_ia32_lfence, "v", "", "sse2") TARGET_HEADER_BUILTIN(_mm_lfence, "v", "h", "emmintrin.h", ALL_LANGUAGES, "sse2") TARGET_BUILTIN(__builtin_ia32_mfence, "v", "", "sse2") TARGET_HEADER_BUILTIN(_mm_mfence, "v", "h", "emmintrin.h", ALL_LANGUAGES, "sse2") -TARGET_BUILTIN(__builtin_ia32_pause, "v", "", "sse2") -TARGET_HEADER_BUILTIN(_mm_pause, "v", "h", "emmintrin.h", ALL_LANGUAGES, "sse2") +TARGET_BUILTIN(__builtin_ia32_pause, "v", "", "") +TARGET_HEADER_BUILTIN(_mm_pause, "v", "h", "emmintrin.h", ALL_LANGUAGES, "") TARGET_BUILTIN(__builtin_ia32_pmuludq128, "V2LLiV4iV4i", "", "sse2") TARGET_BUILTIN(__builtin_ia32_psraw128, "V8sV8sV8s", "", "sse2") TARGET_BUILTIN(__builtin_ia32_psrad128, "V4iV4iV4i", "", "sse2") diff --git a/clang/test/CodeGen/pause.c b/clang/test/CodeGen/pause.c new file mode 100644 index 0000000..1a8e10a --- /dev/null +++ b/clang/test/CodeGen/pause.c @@ -0,0 +1,11 @@ +// RUN: %clang_cc1 -ffreestanding %s -triple=i386-pc-win32 -target-feature -sse2 -emit-llvm -o - -Wall -Werror | FileCheck %s +// RUN: %clang_cc1 -ffreestanding %s -triple=i386-pc-win32 -target-feature +sse2 -emit-llvm -o - -Wall -Werror | FileCheck %s + + +#include + +void test_mm_pause() { + // CHECK-LABEL: test_mm_pause + // CHECK: call void @llvm.x86.sse2.pause() + return _mm_pause(); +} -- 2.7.4