From c5d8b4291b0b4844d28f241540f6205584b14051 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 git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@310191 91177308-0d34-0410-b5e6-96231b3b80d8 --- include/clang/Basic/BuiltinsX86.def | 4 ++-- test/CodeGen/pause.c | 11 +++++++++++ 2 files changed, 13 insertions(+), 2 deletions(-) create mode 100644 test/CodeGen/pause.c diff --git a/include/clang/Basic/BuiltinsX86.def b/include/clang/Basic/BuiltinsX86.def index a516bf6bf0..6d3a478ac3 100644 --- a/include/clang/Basic/BuiltinsX86.def +++ b/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/test/CodeGen/pause.c b/test/CodeGen/pause.c new file mode 100644 index 0000000000..1a8e10aec0 --- /dev/null +++ b/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(); +} -- 2.40.0