Add an identity, Or8(x,0) --> x.

git-svn-id: svn://svn.valgrind.org/vex/trunk@1133

diff --git a/VEX/priv/ir/iropt.c b/VEX/priv/ir/iropt.c
index 724b8036e6df55c95839e46b11af8acdc605adc5..2f5769de82794fca8f3b55b94cc39ec76680138f 100644 (file)
--- a/VEX/priv/ir/iropt.c
+++ b/VEX/priv/ir/iropt.c
@@ -1228,6 +1228,13 @@ static IRExpr* fold_Expr ( IRExpr* e )
             e2 = e->Iex.Binop.arg1;
          } else
 
+         /* Or8(x,0) ==> x */
+         if ((e->Iex.Binop.op == Iop_Or8)
+             && e->Iex.Binop.arg2->tag == Iex_Const
+             && e->Iex.Binop.arg2->Iex.Const.con->Ico.U8 == 0) {
+            e2 = e->Iex.Binop.arg1;
+         } else
+
          /* Or32/Add32(x,0) ==> x */
          if ((e->Iex.Binop.op == Iop_Add32 || e->Iex.Binop.op == Iop_Or32)
              && e->Iex.Binop.arg2->tag == Iex_Const