[llvm] [IR][DSE] Support non-malloc functions in malloc+memset->calloc fold (PR #138299)

[Nikita Popov via llvm-commits]

================
@@ -2377,6 +2377,33 @@ void Verifier::verifyFunctionAttrs(FunctionType *FT, AttributeList Attrs,
       CheckFailed("'allockind()' can't be both zeroed and uninitialized");
   }
 
+  if (Attribute A = Attrs.getFnAttr("alloc-variant-zeroed"); A.isValid()) {
+    StringRef S = A.getValueAsString();
+    Check(!S.empty(), "'alloc-variant-zeroed' must not be empty");
+    if (const Function *F = dyn_cast<Function>(V)) {
+      if (Function *Variant = F->getParent()->getFunction(S)) {
+        Attribute Family = Attrs.getFnAttr("alloc-family");
+        Attribute VariantFamily = Variant->getFnAttribute("alloc-family");
+        if (Family.isValid())
+          Check(VariantFamily.isValid() && VariantFamily.getValueAsString() ==
+                                               Family.getValueAsString(),
+                "'alloc-variant-zeroed' must name a function belonging to the "
+                "same 'alloc-family'");
+
+        Check(
+            Variant->hasFnAttribute(Attribute::AllocKind) &&
+                (Variant->getFnAttribute(Attribute::AllocKind).getAllocKind() &
+                 AllocFnKind::Zeroed) != AllocFnKind::Unknown,
+            "'alloc-variant-zeroed' must name a function with "
+            "'allockind(\"zeroed\")'");
+
+        Check(F->getFunctionType() == Variant->getFunctionType(),
----------------
nikic wrote:

```suggestion
        Check(FT == Variant->getFunctionType(),
```
And then you can drop the  `if (const Function *F = dyn_cast<Function>(V))` bit?

https://github.com/llvm/llvm-project/pull/138299