[PATCH] D144451: [X86] Optimize umax(X,1)

[Simon Pilgrim via Phabricator via llvm-commits]

RKSimon added inline comments.


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Comment at: llvm/lib/Target/X86/X86ISelLowering.cpp:47439
+  if (CC == X86::COND_AE && isOneConstant(FalseOp) &&
+      Cond.getOpcode() == X86ISD::SUB && Cond.hasOneUse()) {
+    SDValue Cond0 = Cond.getOperand(0);
----------------
Cond.hasOneUse() will only check the sub flags output has one use - what about the sub result? Cond->hasOneUse()?


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Comment at: llvm/lib/Target/X86/X86ISelLowering.cpp:47443
+      Cond0 = Cond0.getOperand(0);
+    ConstantSDNode *Sub1C = dyn_cast<ConstantSDNode>(Cond.getOperand(1));
+    if (Cond0 == TrueOp && Sub1C && Sub1C->getZExtValue() == 2) {
----------------
(style) auto *Sub1C = 


Repository:
  rG LLVM Github Monorepo

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  https://reviews.llvm.org/D144451/new/

https://reviews.llvm.org/D144451