[llvm] c7e5883 - [RISCV] Minor cleanups to performSUBCombine. NFC

[Craig Topper via llvm-commits]

Author: Craig Topper
Date: 2022-08-16T12:59:16-07:00
New Revision: c7e58836e8799f32f546c52e4c32ae131ecf141e

URL: https://github.com/llvm/llvm-project/commit/c7e58836e8799f32f546c52e4c32ae131ecf141e
DIFF: https://github.com/llvm/llvm-project/commit/c7e58836e8799f32f546c52e4c32ae131ecf141e.diff

LOG: [RISCV] Minor cleanups to performSUBCombine. NFC

-Rename variable NnzC -> N0C.
-Use SelectionDAG::getSetCC to reduce code.
-Use SDValue::getOperand instead of operator-> and SDNode::getOperand.

Initial steps to add another similar combine to this code.

Added: 
    

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

Removed: 
    


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diff  --git a/llvm/lib/Target/RISCV/RISCVISelLowering.cpp b/llvm/lib/Target/RISCV/RISCVISelLowering.cpp
index 5dd3e38cc2d41..8000c931611c4 100644
--- a/llvm/lib/Target/RISCV/RISCVISelLowering.cpp
+++ b/llvm/lib/Target/RISCV/RISCVISelLowering.cpp
@@ -8288,17 +8288,15 @@ static SDValue performSUBCombine(SDNode *N, SelectionDAG &DAG) {
   // NODE: constant == 0, No redundant instructions are generated.
   // (sub constant, (setcc x, y, eq/neq)) ->
   // (add (setcc x, y, neq/eq), constant - 1)
-  auto *Nnz0 = dyn_cast<ConstantSDNode>(N0);
-  if (Nnz0 && N1.getOpcode() == ISD::SETCC && N1.hasOneUse()) {
-    const auto *CC = cast<CondCodeSDNode>(N1->getOperand(2));
-    ISD::CondCode CCVal = CC->get();
-    if (!Nnz0->isZero() && isIntEqualitySetCC(CCVal)) {
+  auto *N0C = dyn_cast<ConstantSDNode>(N0);
+  if (N0C && N1.getOpcode() == ISD::SETCC && N1.hasOneUse()) {
+    ISD::CondCode CCVal = cast<CondCodeSDNode>(N1.getOperand(2))->get();
+    if (!N0C->isZero() && isIntEqualitySetCC(CCVal)) {
       EVT VT = N->getValueType(0);
-      const APInt &ImmVal = Nnz0->getAPIntValue();
-      SDValue CCInverse =
-          DAG.getCondCode(ISD::getSetCCInverse(CCVal, N0.getValueType()));
-      SDValue NewN0 = DAG.getNode(ISD::SETCC, SDLoc(N), VT, N1->getOperand(0),
-                                  N1->getOperand(1), CCInverse);
+      const APInt &ImmVal = N0C->getAPIntValue();
+      CCVal = ISD::getSetCCInverse(CCVal, N0.getValueType());
+      SDValue NewN0 =
+          DAG.getSetCC(SDLoc(N), VT, N1.getOperand(0), N1.getOperand(1), CCVal);
       SDValue NewN1 = DAG.getConstant(ImmVal - 1, SDLoc(N), VT);
       return DAG.getNode(ISD::ADD, SDLoc(N), VT, NewN0, NewN1);
     }