From: Julian Seward <jseward@acm.org>
Date: Wed, 25 Apr 2012 16:47:53 +0000 (+0000)
Subject: Try to fold out some of the lousy code generated by the amd64 front
X-Git-Tag: svn/VALGRIND_3_8_1^2~163
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=83bf1cbcdb8e7e428042488b2b8c7418062d1bd1;p=thirdparty%2Fvalgrind.git

Try to fold out some of the lousy code generated by the amd64 front
end for 32 bit shifts.


git-svn-id: svn://svn.valgrind.org/vex/trunk@2315
---

diff --git a/VEX/priv/ir_opt.c b/VEX/priv/ir_opt.c
index 5bf44fd104..240d89e7de 100644
--- a/VEX/priv/ir_opt.c
+++ b/VEX/priv/ir_opt.c
@@ -4514,6 +4514,33 @@ static IRExpr* fold_IRExpr_Unop ( IROp op, IRExpr* aa )
       /* 32Uto64( 16Uto32( x )) --> 16Uto64(x) */
       if (is_Unop(aa, Iop_16Uto32))
          return IRExpr_Unop(Iop_16Uto64, aa->Iex.Unop.arg);
+      /* 32Uto64(64to32( Shr64( 32Uto64(64to32(x)), sh ))
+                     --> Shr64( 32Uto64(64to32(x)), sh )) */
+      if (is_Unop(aa, Iop_64to32)
+          && is_Binop(aa->Iex.Unop.arg, Iop_Shr64)
+          && is_Unop(aa->Iex.Unop.arg->Iex.Binop.arg1, Iop_32Uto64)
+          && is_Unop(aa->Iex.Unop.arg->Iex.Binop.arg1->Iex.Unop.arg,
+                     Iop_64to32)) {
+         return aa->Iex.Unop.arg;
+      }
+      /*     32Uto64(64to32( Shl64( 32Uto64(64to32(x)), sh ))
+         --> 32Uto64(64to32( Shl64(                x,   sh )) */
+      if (is_Unop(aa, Iop_64to32)
+          && is_Binop(aa->Iex.Unop.arg, Iop_Shl64)
+          && is_Unop(aa->Iex.Unop.arg->Iex.Binop.arg1, Iop_32Uto64)
+          && is_Unop(aa->Iex.Unop.arg->Iex.Binop.arg1->Iex.Unop.arg,
+                     Iop_64to32)) {
+         return
+            IRExpr_Unop(
+               Iop_32Uto64,
+               IRExpr_Unop(
+                  Iop_64to32,
+                  IRExpr_Binop(
+                     Iop_Shl64, 
+                     aa->Iex.Unop.arg->Iex.Binop.arg1->Iex.Unop.arg->Iex.Unop.arg,
+                     aa->Iex.Unop.arg->Iex.Binop.arg2
+            )));
+      }
       break;
 
    case Iop_1Sto32:
@@ -4529,7 +4556,6 @@ static IRExpr* fold_IRExpr_Unop ( IROp op, IRExpr* aa )
       }
       break;
 
-
    default:
       break;
    }