[llvm] [SCEV] Teach SCEVExpander to use zext nneg when possible (PR #70815)

[Nikita Popov via llvm-commits]

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@@ -1293,7 +1293,10 @@ Value *SCEVExpander::visitTruncateExpr(const SCEVTruncateExpr *S) {
 
 Value *SCEVExpander::visitZeroExtendExpr(const SCEVZeroExtendExpr *S) {
   Value *V = expand(S->getOperand());
-  return Builder.CreateZExt(V, S->getType());
+  auto *Res = Builder.CreateZExt(V, S->getType());
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nikic wrote:

We should add a IsNNeg bool param to IRBuilder::CreateZExt.

https://github.com/llvm/llvm-project/pull/70815