[llvm] [DAG] Handle truncated splat in isBoolConstant (PR #145473)

[Simon Pilgrim via llvm-commits]

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@@ -4375,6 +4375,8 @@ class LLVM_ABI TargetLowering : public TargetLoweringBase {
            Op.getOpcode() == ISD::SPLAT_VECTOR_PARTS;
   }
 
+  virtual bool isTargetCanonicalSelect(SDNode *N) const { return false; }
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RKSimon wrote:

@phoebewang I've created #145724 to investigate this - I'm not yet sure how much yak shaving will be necessary to address the remaining regressions

https://github.com/llvm/llvm-project/pull/145473