From a58bc25aa53079ae73234978f218fc96666783c3 Mon Sep 17 00:00:00 2001
From: Josh Berdine <jjb@fb.com>
Date: Mon, 24 Jun 2019 14:11:45 -0700
Subject: [PATCH] [sledge] Strengthen simplification of convert Exps

Summary:
Simplify all conversions between castable types to the identity. The
backend treats castable types as equal, so distinguishing conversions
between them is incomplete.

Reviewed By: kren1

Differential Revision: D15972427

fbshipit-source-id: fa09859ac
---
 sledge/src/llair/exp.ml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/sledge/src/llair/exp.ml b/sledge/src/llair/exp.ml
index 30e54d1fb..f06328bb9 100644
--- a/sledge/src/llair/exp.ml
+++ b/sledge/src/llair/exp.ml
@@ -690,7 +690,7 @@ let minus_one (typ : Typ.t) =
 
 let simp_convert signed (dst : Typ.t) src arg =
   match (dst, arg) with
-  | _ when Typ.equal dst src -> arg
+  | _ when Typ.castable dst src -> arg
   | Integer {bits= m}, Integer {data; typ= Integer {bits= n}} ->
       integer (Z.clamp ~signed (min m n) data) dst
   | _ -> App {op= Convert {signed; dst; src}; arg}