ir_opt.c: Algebraic simplification for Iop_Add.

The simplification rules for IopAdd32/64 also apply for Iop_Add8/16.

diff --git a/VEX/priv/ir_opt.c b/VEX/priv/ir_opt.c
index 86f3fad276b40ffe8a2dd57a12ec3420f361752e..84bc4e021ff2d41963b05a61477ce3fd0200b130 100644 (file)
--- a/VEX/priv/ir_opt.c
+++ b/VEX/priv/ir_opt.c
@@ -2625,37 +2625,31 @@ static IRExpr* fold_Expr_WRK ( IRExpr** env, IRExpr* e )
                break;
 
             case Iop_Add8:
-               /* Add8(t,t) ==> t << 1.
-                  Memcheck doesn't understand that
-                  x+x produces a defined least significant bit, and it seems
-                  simplest just to get rid of the problem by rewriting it
-                  out, since the opportunity to do so exists. */
-               if (sameIRExprs(env, e->Iex.Binop.arg1, e->Iex.Binop.arg2)) {
-                  e2 = IRExpr_Binop(Iop_Shl8, e->Iex.Binop.arg1,
-                                    IRExpr_Const(IRConst_U8(1)));
-                  break;
-               }
-               break;
-
-               /* NB no Add16(t,t) case yet as no known test case exists */
-
+            case Iop_Add16:
             case Iop_Add32:
             case Iop_Add64:
-               /* Add32/Add64(x,0) ==> x */
+               /* Add8/Add16/Add32/Add64(x,0) ==> x */
                if (isZeroU(e->Iex.Binop.arg2)) {
                   e2 = e->Iex.Binop.arg1;
                   break;
                }
-               /* Add32/Add64(0,x) ==> x */
+               /* Add8/Add16/Add32/Add64(0,x) ==> x */
                if (isZeroU(e->Iex.Binop.arg1)) {
                   e2 = e->Iex.Binop.arg2;
                   break;
                }
-               /* Add32/Add64(t,t) ==> t << 1. Same rationale as for Add8. */
+               /* Add8/Add16/Add32/Add64(t,t) ==> t << 1.
+                  Memcheck doesn't understand that
+                  x+x produces a defined least significant bit, and it seems
+                  simplest just to get rid of the problem by rewriting it
+                  out, since the opportunity to do so exists. */
                if (sameIRExprs(env, e->Iex.Binop.arg1, e->Iex.Binop.arg2)) {
-                  e2 = IRExpr_Binop(
-                          e->Iex.Binop.op == Iop_Add32 ? Iop_Shl32 : Iop_Shl64,
-                          e->Iex.Binop.arg1, IRExpr_Const(IRConst_U8(1)));
+                  IROp add_op = e->Iex.Binop.op;
+                  IROp shift_op = (add_op == Iop_Add64) ? Iop_Shl64 :
+                                  (add_op == Iop_Add32) ? Iop_Shl32 :
+                                  (add_op == Iop_Add16) ? Iop_Shl16 : Iop_Shl8;
+                  e2 = IRExpr_Binop(shift_op, e->Iex.Binop.arg1,
+                                    IRExpr_Const(IRConst_U8(1)));
                   break;
                }
                break;