[llvm] 199ac3a - [NFC][X86] Sret return register cleanup

[Nathan Sidwell via llvm-commits]

Author: Nathan Sidwell
Date: 2021-08-27T04:03:49-07:00
New Revision: 199ac3a839d900a5274da019c0dca41aac61cf2c

URL: https://github.com/llvm/llvm-project/commit/199ac3a839d900a5274da019c0dca41aac61cf2c
DIFF: https://github.com/llvm/llvm-project/commit/199ac3a839d900a5274da019c0dca41aac61cf2c.diff

LOG: [NFC][X86] Sret return register cleanup

There are no paths into LowerFormalParms that have already specified
the sret register. We always materialize a virtual and then assign it
to the physical reg at the point of the return.

Differential Revision: https://reviews.llvm.org/D108762

Added: 
    

Modified: 
    llvm/lib/Target/X86/X86ISelLowering.cpp

Removed: 
    


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diff  --git a/llvm/lib/Target/X86/X86ISelLowering.cpp b/llvm/lib/Target/X86/X86ISelLowering.cpp
index b2189ccb1987..2d48e714c2fc 100644
--- a/llvm/lib/Target/X86/X86ISelLowering.cpp
+++ b/llvm/lib/Target/X86/X86ISelLowering.cpp
@@ -3960,12 +3960,12 @@ SDValue X86TargetLowering::LowerFormalArguments(
     // the argument into a virtual register so that we can access it from the
     // return points.
     if (Ins[I].Flags.isSRet()) {
-      Register Reg = FuncInfo->getSRetReturnReg();
-      if (!Reg) {
-        MVT PtrTy = getPointerTy(DAG.getDataLayout());
-        Reg = MF.getRegInfo().createVirtualRegister(getRegClassFor(PtrTy));
-        FuncInfo->setSRetReturnReg(Reg);
-      }
+      assert(!FuncInfo->getSRetReturnReg() &&
+             "SRet return has already been set");
+      MVT PtrTy = getPointerTy(DAG.getDataLayout());
+      Register Reg =
+          MF.getRegInfo().createVirtualRegister(getRegClassFor(PtrTy));
+      FuncInfo->setSRetReturnReg(Reg);
       SDValue Copy = DAG.getCopyToReg(DAG.getEntryNode(), dl, Reg, InVals[I]);
       Chain = DAG.getNode(ISD::TokenFactor, dl, MVT::Other, Copy, Chain);
       break;