[llvm] [CVP] Infer nneg on existing zext (PR #72052)

[Nikita Popov via llvm-commits]

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@@ -1032,6 +1033,24 @@ static bool processSExt(SExtInst *SDI, LazyValueInfo *LVI) {
   return true;
 }
 
+static bool processZExt(ZExtInst *SDI, LazyValueInfo *LVI) {
+  if (SDI->getType()->isVectorTy())
+    return false;
+
+  if (SDI->hasNonNeg())
+    return false;
+
+  const Use &Base = SDI->getOperandUse(0);
+  if (!LVI->getConstantRangeAtUse(Base, /*UndefAllowed*/ false)
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nikic wrote:

I don't think it does. It has a dominating condition. I would expect something like a select condition for at-use.

https://github.com/llvm/llvm-project/pull/72052