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Re: PTR-PLUS merge into the mainline
Hi,
On Thu, 28 Jun 2007, Andrew_Pinski@PlayStation.Sony.Com wrote:
> Roman Zippel <zippel@linux-m68k.org> wrote on 06/28/2007 07:54:43 PM:
>
> > Hi,
> > Notice that it generates the (i + 1) * 4 instead of (i * 4) + 4 as with
> > the other cases. While I tried to debug this I narrowed it down to the
> > changes in fold_binary(), but I don't really know how to fix this, so
> > I could use some help here.
>
> The main thing is that this is really PR 32120. The problem is only
> related to the
> merge because of the way fold_binary works.
I'm not sure that's related, what's happening in my example is that the
call to fold_plusminus_mult_expr() defeats the optimization attempted in
pointer_int_sum(). If I use the patch below to restrict the condition, my
problem is fixed, but PR32120 is unchanged.
Actually if I compare the final_cleanup dump of PR32120 with the output
from gcc 4.1, they are basically identical.
bye, Roman
---
gcc/fold-const.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
Index: gcc/gcc/fold-const.c
===================================================================
--- gcc.orig/gcc/fold-const.c
+++ gcc/gcc/fold-const.c
@@ -9173,8 +9173,8 @@ fold_binary (enum tree_code code, tree t
/* Handle (A1 * C1) + (A2 * C2) with A1, A2 or C1, C2 being the
same or one. */
- if ((TREE_CODE (arg0) == MULT_EXPR
- || TREE_CODE (arg1) == MULT_EXPR)
+ if (TREE_CODE (arg0) == MULT_EXPR
+ && TREE_CODE (arg1) == MULT_EXPR
&& (!FLOAT_TYPE_P (type) || flag_unsafe_math_optimizations))
{
tree tem = fold_plusminus_mult_expr (code, type, arg0, arg1);