Commit 7c0247e3 authored by Hans Wennborg's avatar Hans Wennborg
Browse files

Merging r326393: 

------------------------------------------------------------------------
r326393 | ctopper | 2018-03-01 01:08:38 +0100 (Thu, 01 Mar 2018) | 5 lines

[X86] Make sure we don't combine (fneg (fma X, Y, Z)) to a target specific node when there are no FMA instructions.

This would cause a 'cannot select' error at isel when we should have emitted a lib call and an xor.

Fixes PR36553.
------------------------------------------------------------------------

llvm-svn: 326423
parent 2c62a710

llvm/lib/Target/X86/X86ISelLowering.cpp

+1 −1
Original line number Diff line number Diff line
@@ -35520,7 +35520,7 @@ static SDValue combineFneg(SDNode *N, SelectionDAG &DAG, 
  // If we're negating an FMA node, then we can adjust the

  // instruction to include the extra negation.

  unsigned NewOpcode = 0;

  if (Arg.hasOneUse()) {

  if (Arg.hasOneUse() && Subtarget.hasAnyFMA()) {

    switch (Arg.getOpcode()) {

    case ISD::FMA:             NewOpcode = X86ISD::FNMSUB;       break;

    case X86ISD::FMSUB:        NewOpcode = X86ISD::FNMADD;       break;

llvm/test/CodeGen/X86/pr36553.ll

0 → 100644
+20 −0
Original line number Diff line number Diff line 
; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py

; RUN: llc < %s -mtriple=x86_64-apple-darwin10 | FileCheck %s



; Make sure we don't crash because we negated an fma when we didn't have any fma instructions.



define float @pr36553(float %a, float %b, float %c) nounwind {

; CHECK-LABEL: pr36553:

; CHECK:       ## %bb.0: ## %entry

; CHECK-NEXT:    pushq %rax

; CHECK-NEXT:    callq _fmaf

; CHECK-NEXT:    xorps {{.*}}(%rip), %xmm0

; CHECK-NEXT:    popq %rax

; CHECK-NEXT:    retq

entry:

  %0 = tail call float @llvm.fma.f32(float %a, float %b, float %c)

  %sub = fsub float -0.000000e+00, %0

  ret float %sub

}



declare float @llvm.fma.f32(float, float, float)