[llvm] [InstCombine] Fold A pred C ? (A >> BW - 1) : 1 --> ZExt(A pred C ? A < 0 : 1) (PR #69961)

[via llvm-commits]

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@@ -3409,6 +3409,25 @@ Instruction *InstCombinerImpl::visitSelectInst(SelectInst &SI) {
       return replaceOperand(SI, 2, S);
   }
 
+  {
+    // A pred C ? (A >> BW - 1) : 1 --> ZExt(A pred C ? A < 0 : 1)
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elhewaty wrote:

@goldsteinn, Should I fold `A < 0` instead of `A Pred C`? or draft the patch until we can demonstrate that it benefits some real-world applications 

https://github.com/llvm/llvm-project/pull/69961