Index: llvm/trunk/lib/Target/X86/X86InstrSSE.td =================================================================== --- llvm/trunk/lib/Target/X86/X86InstrSSE.td +++ llvm/trunk/lib/Target/X86/X86InstrSSE.td @@ -3695,8 +3695,7 @@ // Pause. This "instruction" is encoded as "rep; nop", so even though it // was introduced with SSE2, it's backward compatible. def PAUSE : I<0x90, RawFrm, (outs), (ins), - "pause", [(int_x86_sse2_pause)], IIC_SSE_PAUSE>, - OBXS, Requires<[HasSSE2]>; + "pause", [(int_x86_sse2_pause)], IIC_SSE_PAUSE>, OBXS; } let SchedRW = [WriteFence] in { Index: llvm/trunk/test/CodeGen/X86/pause.ll =================================================================== --- llvm/trunk/test/CodeGen/X86/pause.ll +++ llvm/trunk/test/CodeGen/X86/pause.ll @@ -0,0 +1,15 @@ +; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py +; RUN: llc < %s -disable-peephole -mtriple=i386-apple-darwin -mattr=-sse -show-mc-encoding | FileCheck %s +; RUN: llc < %s -disable-peephole -mtriple=i386-apple-darwin -mattr=-avx,+sse2 -show-mc-encoding | FileCheck %s +; RUN: llc < %s -disable-peephole -mtriple=i386-apple-darwin -mattr=+avx2 -show-mc-encoding | FileCheck %s +; RUN: llc < %s -disable-peephole -mtriple=i386-apple-darwin -mcpu=skx -show-mc-encoding | FileCheck %s + +define void @test_x86_sse2_pause() { +; CHECK-LABEL: test_x86_sse2_pause: +; CHECK: ## BB#0: +; CHECK-NEXT: pause ## encoding: [0xf3,0x90] +; CHECK-NEXT: retl ## encoding: [0xc3] + tail call void @llvm.x86.sse2.pause() + ret void +} +declare void @llvm.x86.sse2.pause() nounwind