[PATCH] D158634: [RISCV] Fix wrong operand being used for VL in shift combine

[Luke Lau via Phabricator via llvm-commits]

luke created this revision.
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At some point a merge operand was added to the binary vl ops, so this combine
was using the mask for the VL. This causes a crash when trying to 
select the vmv_v_x_vl, which showed up locally when messing about with 
selectVSplat, but thankfully in ToT the vmv_v_x_vl gets pattern matched 
away into the .vx and .vi operands every time, so there's no noticeable 
change.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D158634

Files:
  llvm/lib/Target/RISCV/RISCVISelLowering.cpp


Index: llvm/lib/Target/RISCV/RISCVISelLowering.cpp
===================================================================
--- llvm/lib/Target/RISCV/RISCVISelLowering.cpp
+++ llvm/lib/Target/RISCV/RISCVISelLowering.cpp
@@ -13456,7 +13456,7 @@
     if (ShAmt.getOpcode() == RISCVISD::SPLAT_VECTOR_SPLIT_I64_VL) {
       // We don't need the upper 32 bits of a 64-bit element for a shift amount.
       SDLoc DL(N);
-      SDValue VL = N->getOperand(3);
+      SDValue VL = N->getOperand(4);
       EVT VT = N->getValueType(0);
       ShAmt = DAG.getNode(RISCVISD::VMV_V_X_VL, DL, VT, DAG.getUNDEF(VT),
                           ShAmt.getOperand(1), VL);


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