From: Julian Seward <jseward@acm.org>
Date: Tue, 1 Mar 2005 10:19:23 +0000 (+0000)
Subject: Add a constant folding rule for MullS32.
X-Git-Tag: svn/VALGRIND_3_0_1^2~343
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=393006557006c28265a0c01302391e08ec72d41a;p=thirdparty%2Fvalgrind.git

Add a constant folding rule for MullS32.


git-svn-id: svn://svn.valgrind.org/vex/trunk@991
---

diff --git a/VEX/priv/ir/iropt.c b/VEX/priv/ir/iropt.c
index 52daf92646..ac5dba839a 100644
--- a/VEX/priv/ir/iropt.c
+++ b/VEX/priv/ir/iropt.c
@@ -1047,6 +1047,19 @@ static IRExpr* fold_Expr ( IRExpr* e )
                        (e->Iex.Binop.arg1->Iex.Const.con->Ico.U32
                         * e->Iex.Binop.arg2->Iex.Const.con->Ico.U32)));
                break;
+            case Iop_MullS32: {
+               /* very paranoid */
+               UInt  u32a = e->Iex.Binop.arg1->Iex.Const.con->Ico.U32;
+               UInt  u32b = e->Iex.Binop.arg2->Iex.Const.con->Ico.U32;
+               Int   s32a = (Int)u32a;
+               Int   s32b = (Int)u32b;
+               Long  s64a = (Long)s32a;
+               Long  s64b = (Long)s32b;
+               Long  sres = s64a * s64b;
+               ULong ures = (ULong)sres;
+               e2 = IRExpr_Const(IRConst_U64(ures));
+               break;
+            }
 
             /* -- Shl -- */
             case Iop_Shl32: