Re: [PATCH]: Fix pointer arithmetic handling in tree-ssa-structalias.c

[Grigory Zagorodnev <grigory_zagorodnev at linux dot intel dot com>]

Daniel,
Your patch caused cpu2006/gcc to fail (results miscompare) at -O2 
optimization level with 'test' dataset on ia32.

- Grigory

Daniel Berlin wrote:
> Without this patch, we are currently considering *(p + x) and *(p + y)
> to point to the same thing, even when x and y are not equal.
>
> This is due to a missing else clause.
>
> Fixed thusly.
>
> This fixes SPEC2006 (and vect-101 on osx darwin).
>
> Bootstrapped and regtested on i686-darwin
>
> Committed to mainline.
>
> 2006-12-11  Daniel Berlin  <dberlin@dberlin.org>
>
>        * tree-ssa-structalias.c (handle_ptr_arith): Return false when we
>        can't handle the pointer arithmetic.
>
> --Dan
>
>
> ------------------------------------------------------------------------
>
> --- gcc/tree-ssa-structalias.c	(/mirror/gcc-trunk)	(revision 665)
> +++ gcc/tree-ssa-structalias.c	(/local/gcc-clean)	(revision 665)
> @@ -2871,6 +2871,8 @@ handle_ptr_arith (VEC (ce_s, heap) *lhsc
>      {
>        rhsoffset = TREE_INT_CST_LOW (op1) * BITS_PER_UNIT;
>      }
> +  else
> +    return false;
>  
>  
>    for (i = 0; VEC_iterate (ce_s, lhsc, i, c); i++)
>
> Property changes on: 
> ___________________________________________________________________
> Name: svk:merge
>  +138bc75d-0d04-0410-961f-82ee72b054a4:/trunk:119760
>  +23c3ee16-a423-49b3-8738-b114dc1aabb6:/local/gcc-pta-dev:259
>  +23c3ee16-a423-49b3-8738-b114dc1aabb6:/local/gcc-trunk:531
>  +7dca8dba-45c1-47dc-8958-1a7301c5ed47:/local-gcc/md-constraint:113709
>  +f367781f-d768-471e-ba66-e306e17dff77:/local/gen-rework-20060122:110130