PR10136: fix PPCTargetLowering::LowerCall_SVR4 so that a necessary CopyToReg doesn't appear to be dead.

Roman, since you're writing tests for other PPC-SVR4 vararg-related stuff, would you mind writing a test for this?

llvm-svn: 133018

1 files changed, 6 insertions, 7 deletions

diff --git a/llvm/lib/Target/PowerPC/PPCISelLowering.cpp b/llvm/lib/Target/PowerPC/PPCISelLowering.cpp
index dbb184c1f6b..55c15ec4f86 100644
--- a/llvm/lib/Target/PowerPC/PPCISelLowering.cpp
+++ b/llvm/lib/Target/PowerPC/PPCISelLowering.cpp
@@ -2902,6 +2902,12 @@ PPCTargetLowering::LowerCall_SVR4(SDValue Chain, SDValue Callee,
     Chain = DAG.getNode(ISD::TokenFactor, dl, MVT::Other,
                         &MemOpChains[0], MemOpChains.size());
 
+  // Set CR6 to true if this is a vararg call.
+  if (isVarArg) {
+    SDValue SetCR(DAG.getMachineNode(PPC::CRSET, dl, MVT::i32), 0);
+    RegsToPass.push_back(std::make_pair(unsigned(PPC::CR1EQ), SetCR));
+  }
+
   // Build a sequence of copy-to-reg nodes chained together with token chain
   // and flag operands which copy the outgoing args into the appropriate regs.
   SDValue InFlag;
@@ -2911,13 +2917,6 @@ PPCTargetLowering::LowerCall_SVR4(SDValue Chain, SDValue Callee,
     InFlag = Chain.getValue(1);
   }
 
-  // Set CR6 to true if this is a vararg call.
-  if (isVarArg) {
-    SDValue SetCR(DAG.getMachineNode(PPC::CRSET, dl, MVT::i32), 0);
-    Chain = DAG.getCopyToReg(Chain, dl, PPC::CR1EQ, SetCR, InFlag);
-    InFlag = Chain.getValue(1);
-  }
-
   if (isTailCall)
     PrepareTailCall(DAG, InFlag, Chain, dl, false, SPDiff, NumBytes, LROp, FPOp,
                     false, TailCallArguments);