[Mlir-commits] [mlir] [mlir][arith] Check overflow when reassociating integer constants (PR #233155)

[Krzysztof Drewniak]

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@@ -42,9 +42,20 @@ def OrIntAttrs : NativeCodeCall<"orIntegerAttrs($_builder, $0, $1, $2)">;
 // Bitwise-xor two integer attributes and create a new one with the result.
 def XorIntAttrs : NativeCodeCall<"xorIntegerAttrs($_builder, $0, $1, $2)">;
 
-// Merge overflow flags from 2 ops, selecting the most conservative combination.
+// Intersect overflow flags. Callers must ensure the common flags remain valid
+// after rewriting.
 def MergeOverflow : NativeCodeCall<"mergeOverflowFlags($0, $1)">;
 
+// For fixed-width integers, retain common flags only if the constant arithmetic
+// does not overflow in their respective signedness. Pass constants in folding
+// order.
+class MergeOverflowForReassociation<string op> : NativeCodeCall<
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krzysz00 wrote:

Huh, that's a clever construct

https://github.com/llvm/llvm-project/pull/233155