From: Julian Seward <jseward@acm.org>
Date: Wed, 13 Oct 2004 16:08:14 +0000 (+0000)
Subject: fold_Expr: do Shl32(x,0) ==> x
X-Git-Tag: svn/VALGRIND_3_0_1^2~1008
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=6c4e691648b835a4e4970172698864850a99d2d1;p=thirdparty%2Fvalgrind.git

fold_Expr: do Shl32(x,0) ==> x


git-svn-id: svn://svn.valgrind.org/vex/trunk@326
---

diff --git a/VEX/priv/ir/iropt.c b/VEX/priv/ir/iropt.c
index 7903bd2d09..b352bf7e74 100644
--- a/VEX/priv/ir/iropt.c
+++ b/VEX/priv/ir/iropt.c
@@ -495,6 +495,13 @@ static IRExpr* fold_Expr ( IRExpr* e )
       } else {
 
          /* other cases (identities, etc) */
+         /* Shl32(x,0) ==> x */
+         if (e->Iex.Binop.op == Iop_Shl32
+             && e->Iex.Binop.arg2->tag == Iex_Const
+             && e->Iex.Binop.arg2->Iex.Const.con->Ico.U32 == 0) {
+            e2 = e->Iex.Binop.arg1;
+         } else
+
          /* Add32(x,0) ==> x */
          if (e->Iex.Binop.op == Iop_Add32
              && e->Iex.Binop.arg2->tag == Iex_Const