[backport proposed 4.8 fix for emit_conditional_add <mikpe@it.uu.se>]

Date: Fri, 24 Aug 2012 15:43:39 -0700
Subject: Re: [PATCH] Fix emit_conditional_add and documentation for add@var{mode}cc
From: Andrew Pinski <pinskia at gmail dot com>
List-Archive: <http://gcc.gnu.org/ml/gcc-patches/>

Forgot to attach the patch.

-- Andrew

On Fri, Aug 24, 2012 at 3:42 PM, Andrew Pinski <pinskia@gmail.com> wrote:
> Hi,
>   I decided to split this patch from the other patch which uses
> emit_conditional_add in expand as that part of the patch needs some
> work.  This part of the patch can be applied separately and it fixes a
> few things dealing with conditional adds.
>
> First the documentation is wrong for the pattern as we do the addition
> if operand 0 is true rather than false.
> Then emit_conditional_add is wrong as you cannot switch around op2 and op3.
>
> OK? Bootstrapped and tested on x86_64-linux-gnu with no regressions.
>
> Thanks,
> Andrew Pinski
>
> ChangeLog:
>  * optabs.c (emit_conditional_add): Correct comment about the arguments.
> Remove code which might swap op2 and op3 since they cannot be swapped.
> * doc/md.texi (add@var{mode}cc): Fix document about how the arguments are used.

--- gcc-4.6.3/gcc/doc/md.texi.~1~	2011-08-12 18:29:29.000000000 +0200
+++ gcc-4.6.3/gcc/doc/md.texi	2012-09-01 14:26:22.000000000 +0200
@@ -4830,7 +4830,7 @@ define these patterns.
 @item @samp{add@var{mode}cc}
 Similar to @samp{mov@var{mode}cc} but for conditional addition.  Conditionally
 move operand 2 or (operands 2 + operand 3) into operand 0 according to the
-comparison in operand 1.  If the comparison is true, operand 2 is moved into
+comparison in operand 1.  If the comparison is false, operand 2 is moved into
 operand 0, otherwise (operand 2 + operand 3) is moved.
 
 @cindex @code{cstore@var{mode}4} instruction pattern
--- gcc-4.6.3/gcc/optabs.c.~1~	2011-03-04 11:27:10.000000000 +0100
+++ gcc-4.6.3/gcc/optabs.c	2012-09-01 14:26:22.000000000 +0200
@@ -4577,7 +4577,7 @@ can_conditionally_move_p (enum machine_m
    the mode to use should they be constants.  If it is VOIDmode, they cannot
    both be constants.
 
-   OP2 should be stored in TARGET if the comparison is true, otherwise OP2+OP3
+   OP2 should be stored in TARGET if the comparison is false, otherwise OP2+OP3
    should be stored there.  MODE is the mode to use should they be constants.
    If it is VOIDmode, they cannot both be constants.
 
@@ -4591,7 +4591,6 @@ emit_conditional_add (rtx target, enum r
 {
   rtx tem, subtarget, comparison, insn;
   enum insn_code icode;
-  enum rtx_code reversed;
 
   /* If one operand is constant, make it the second one.  Only do this
      if the other operand is not constant as well.  */
@@ -4615,16 +4614,6 @@ emit_conditional_add (rtx target, enum r
   if (cmode == VOIDmode)
     cmode = GET_MODE (op0);
 
-  if (swap_commutative_operands_p (op2, op3)
-      && ((reversed = reversed_comparison_code_parts (code, op0, op1, NULL))
-          != UNKNOWN))
-    {
-      tem = op2;
-      op2 = op3;
-      op3 = tem;
-      code = reversed;
-    }
-
   if (mode == VOIDmode)
     mode = GET_MODE (op2);