[Mlir-commits] [mlir] [mlir][arith] doc updates for ub semantics, and int representations (PR #72932)

[Jacob Yu]

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@@ -1422,9 +1437,15 @@ def SelectOp : Arith_Op<"select", [Pure,
   let summary = "select operation";
   let description = [{
     The `arith.select` operation chooses one value based on a binary condition
-    supplied as its first operand. If the value of the first operand is `1`,
-    the second operand is chosen, otherwise the third operand is chosen.
-    The second and the third operand must have the same type.
+    supplied as its first operand. 
+    
+    If the value of the first operand is `1`, then the second operand is returned, 
+    and the third operand is ignored, even if it were poison. 
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pingshiyu wrote:

this is an "exception" on the otherwise assumed poison propagation, so it's said explicitly here that:
even if the third operand is poison, it is still ignored

https://github.com/llvm/llvm-project/pull/72932