From: Florian Krohm <flo2030@eich-krohm.de>
Date: Wed, 3 Sep 2025 15:03:08 +0000 (+0000)
Subject: ir_opt.c:  Algebraic simplification for Iop_Sub.
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=c93dba5adbd5d;p=thirdparty%2Fvalgrind.git

ir_opt.c:  Algebraic simplification for Iop_Sub.

The simplification rules for IopSub32/64 also apply for Iop_Sub8/16.
---

diff --git a/VEX/priv/ir_opt.c b/VEX/priv/ir_opt.c
index 84bc4e021..b362be007 100644
--- a/VEX/priv/ir_opt.c
+++ b/VEX/priv/ir_opt.c
@@ -2654,19 +2654,22 @@ static IRExpr* fold_Expr_WRK ( IRExpr** env, IRExpr* e )
                }
                break;
 
+            case Iop_Sub8:
+            case Iop_Sub16:
             case Iop_Sub32:
             case Iop_Sub64:
-               /* Sub32/Sub64(x,0) ==> x */
+               /* Sub8/Sub16/Sub32/Sub64(x,0) ==> x */
                if (isZeroU(e->Iex.Binop.arg2)) {
                   e2 = e->Iex.Binop.arg1;
                   break;
                }
-               /* Sub32/Sub64(t,t) ==> 0, for some IRTemp t */
+               /* Sub8/Sub16/Sub32/Sub64(t,t) ==> 0, for some IRTemp t */
                if (sameIRExprs(env, e->Iex.Binop.arg1, e->Iex.Binop.arg2)) {
                   e2 = mkZeroOfPrimopResultType(e->Iex.Binop.op);
                   break;
                }
                break;
+
             case Iop_Sub8x16:
                /* Sub8x16(x,0) ==> x */
                if (isZeroV128(e->Iex.Binop.arg2)) {