Commit 6f335f8b authored by Hans Wennborg's avatar Hans Wennborg
Browse files

Merging r310191: 

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r310191 | ctopper | 2017-08-05 16:35:54 -0700 (Sat, 05 Aug 2017) | 18 lines

[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
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llvm-svn: 310294
parent 03a96f4e

clang/include/clang/Basic/BuiltinsX86.def

+2 −2
Original line number Diff line number Diff line
@@ -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")

clang/test/CodeGen/pause.c

0 → 100644
+11 −0
Original line number Diff line number Diff line 
// 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 <x86intrin.h>



void test_mm_pause() {

  // CHECK-LABEL: test_mm_pause

  // CHECK: call void @llvm.x86.sse2.pause()

  return _mm_pause();

}