[llvm] [SelectOpt] Add handling for not conditions. (PR #92517)

[Sotiris Apostolakis via llvm-commits]

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@@ -177,11 +189,22 @@ class SelectOptimizeImpl {
       llvm_unreachable("Unhandled case in getCondition");
     }
 
+    /// Return the condition for the SelectLike instruction. For example the
+    /// condition of a select or c in `or(zext(c), x)`
+    Value *getCondition() const {
+      Value *CC = getNonInvertedCondition();
+      if (Inverted)
+        return cast<Instruction>(CC)->getOperand(0);
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sapostolakis wrote:

add a comment on what type of instruction can be inverted and why it is safe/correct to get the first operand for the condition

https://github.com/llvm/llvm-project/pull/92517