Preserve <undef> flags in ARMExpandPseudo.

This probably mostly shows up in bugpoint-generated code.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@158527 91177308-0d34-0410-b5e6-96231b3b80d8

2 files changed, 14 insertions, 5 deletions

diff --git a/lib/Target/ARM/ARMExpandPseudoInsts.cpp b/lib/Target/ARM/ARMExpandPseudoInsts.cpp
index ac9163f..a242b13 100644
--- a/lib/Target/ARM/ARMExpandPseudoInsts.cpp
+++ b/lib/Target/ARM/ARMExpandPseudoInsts.cpp
@@ -459,22 +459,23 @@ void ARMExpandPseudo::ExpandVST(MachineBasicBlock::iterator &MBBI) {
     MIB.addOperand(MI.getOperand(OpIdx++));
 
   bool SrcIsKill = MI.getOperand(OpIdx).isKill();
+  bool SrcIsUndef = MI.getOperand(OpIdx).isUndef();
   unsigned SrcReg = MI.getOperand(OpIdx++).getReg();
   unsigned D0, D1, D2, D3;
   GetDSubRegs(SrcReg, RegSpc, TRI, D0, D1, D2, D3);
-  MIB.addReg(D0);
+  MIB.addReg(D0, getUndefRegState(SrcIsUndef));
   if (NumRegs > 1 && TableEntry->copyAllListRegs)
-    MIB.addReg(D1);
+    MIB.addReg(D1, getUndefRegState(SrcIsUndef));
   if (NumRegs > 2 && TableEntry->copyAllListRegs)
-    MIB.addReg(D2);
+    MIB.addReg(D2, getUndefRegState(SrcIsUndef));
   if (NumRegs > 3 && TableEntry->copyAllListRegs)
-    MIB.addReg(D3);
+    MIB.addReg(D3, getUndefRegState(SrcIsUndef));
 
   // Copy the predicate operands.
   MIB.addOperand(MI.getOperand(OpIdx++));
   MIB.addOperand(MI.getOperand(OpIdx++));
 
-  if (SrcIsKill) // Add an implicit kill for the super-reg.
+  if (SrcIsKill && !SrcIsUndef) // Add an implicit kill for the super-reg.
     MIB->addRegisterKilled(SrcReg, TRI, true);
   TransferImpOps(MI, MIB, MIB);
 
diff --git a/test/CodeGen/ARM/2012-01-24-RegSequenceLiveRange.ll b/test/CodeGen/ARM/2012-01-24-RegSequenceLiveRange.ll
index 872eca3..f1c85f1 100644
--- a/test/CodeGen/ARM/2012-01-24-RegSequenceLiveRange.ll
+++ b/test/CodeGen/ARM/2012-01-24-RegSequenceLiveRange.ll
@@ -60,8 +60,16 @@ for.end:                                          ; preds = %entry
   ret void
 }
 
+; Check that pseudo-expansion preserves <undef> flags.
+define void @foo3(i8* %p) nounwind ssp {
+entry:
+  tail call void @llvm.arm.neon.vst2.v4f32(i8* %p, <4 x float> undef, <4 x float> undef, i32 4)
+  ret void
+}
+
 declare arm_aapcs_vfpcc void @bar(i8*, float, float, float)
 declare void @llvm.arm.neon.vst1.v4f32(i8*, <4 x float>, i32) nounwind
+declare void @llvm.arm.neon.vst2.v4f32(i8*, <4 x float>, <4 x float>, i32) nounwind
 
 !0 = metadata !{metadata !"omnipotent char", metadata !1}
 !1 = metadata !{metadata !"Simple C/C++ TBAA", null}