[clang] [llvm] [CVP] Infer range return attribute (PR #99620)

[via cfe-commits]

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@@ -1289,6 +1299,14 @@ static bool runImpl(Function &F, LazyValueInfo *LVI, DominatorTree *DT,
     FnChanged |= BBChanged;
   }
 
+  // Infer range attribute on return value.
+  if (RetRange && !RetRange->isFullSet()) {
+    Attribute RangeAttr = F.getRetAttribute(Attribute::Range);
+    if (RangeAttr.isValid())
+      RetRange = RetRange->intersectWith(RangeAttr.getRange());
+    if (!RetRange->isEmptySet() && !RetRange->isSingleElement())
+      F.addRangeRetAttr(*RetRange);
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goldsteinn wrote:

Could we cause an inf loop if existing range attr is same as new one?

https://github.com/llvm/llvm-project/pull/99620