[llvm] ConstantFolding: Do not fold fcmp of denormal without known mode (PR #115407)

[Nikita Popov via llvm-commits]

================
@@ -1266,14 +1266,16 @@ Constant *llvm::ConstantFoldCompareInstOperands(
     return ConstantFoldCompareInstOperands(Predicate, Ops1, Ops0, DL, TLI);
   }
 
-  // Flush any denormal constant float input according to denormal handling
-  // mode.
-  Ops0 = FlushFPConstant(Ops0, I, /* IsOutput */ false);
-  if (!Ops0)
-    return nullptr;
-  Ops1 = FlushFPConstant(Ops1, I, /* IsOutput */ false);
-  if (!Ops1)
-    return nullptr;
+  if (CmpInst::isFPPredicate(Predicate)) {
+    // Flush any denormal constant float input according to denormal handling
+    // mode.
+    Ops0 = FlushFPConstant(Ops0, I, /* IsOutput=*/false);
+    if (!Ops0)
+      return nullptr;
+    Ops1 = FlushFPConstant(Ops1, I, /* IsOutput= */ false);
----------------
nikic wrote:

```suggestion
    Ops1 = FlushFPConstant(Ops1, I, /* IsOutput=*/false);
```

https://github.com/llvm/llvm-project/pull/115407