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Re: PR 58958: wrong aliasing info
- From: Richard Biener <richard dot guenther at gmail dot com>
- To: Marc Glisse <marc dot glisse at inria dot fr>
- Cc: GCC Patches <gcc-patches at gcc dot gnu dot org>
- Date: Tue, 5 Nov 2013 13:05:50 +0100
- Subject: Re: PR 58958: wrong aliasing info
- Authentication-results: sourceware.org; auth=none
- References: <alpine dot DEB dot 2 dot 02 dot 1311012323530 dot 24250 at stedding dot saclay dot inria dot fr> <CAFiYyc0i9pNC=Jpz-1LpUx673fffJY0tDKAqD1AfYm_gbvmKcg at mail dot gmail dot com> <CAFiYyc0v-TwQACBDJ_0LORV4o7O6QBa3aFcDGD+1moZM4fYtYA at mail dot gmail dot com> <alpine dot DEB dot 2 dot 10 dot 1311041215080 dot 4556 at stedding dot saclay dot inria dot fr> <CAFiYyc0of0u8J0Kg4p8hUnRDcEA+a9049HxL34hjTZ84pOdi+w at mail dot gmail dot com> <alpine dot DEB dot 2 dot 10 dot 1311041758590 dot 7063 at stedding dot saclay dot inria dot fr> <e93ef27e-8ab3-47c0-a52d-3dbb0dc37168 at email dot android dot com> <alpine dot DEB dot 2 dot 02 dot 1311051132590 dot 30766 at stedding dot saclay dot inria dot fr>
On Tue, Nov 5, 2013 at 11:40 AM, Marc Glisse <marc.glisse@inria.fr> wrote:
> On Mon, 4 Nov 2013, Richard Biener wrote:
>
>> Well, you cannot use the size argument unchanged for the null return case.
>> You could fallback to get_base_address and -1 size in that case.
>
>
> Like this? Bootstrap+testsuite on x86_64-unknown-linux-gnu.
> (I think I'll disable cilk for my future bootstraps: it takes forever and
> confuses contrib/compare_tests)
Yes, this is ok.
Thanks,
Richard.
> 2013-11-05 Marc Glisse <marc.glisse@inria.fr>
>
> PR tree-optimization/58958
> gcc/
> * tree-ssa-alias.c (ao_ref_init_from_ptr_and_size): Use
> get_addr_base_and_unit_offset instead of get_ref_base_and_extent.
>
>
> gcc/testsuite/
> * gcc.dg/tree-ssa/pr58958.c: New file.
>
> --
> Marc Glisse
>
> Index: gcc/testsuite/gcc.dg/tree-ssa/pr58958.c
> ===================================================================
> --- gcc/testsuite/gcc.dg/tree-ssa/pr58958.c (revision 0)
> +++ gcc/testsuite/gcc.dg/tree-ssa/pr58958.c (working copy)
> @@ -0,0 +1,12 @@
> +/* { dg-do compile } */
> +/* { dg-options "-O2 -fdump-tree-optimized" } */
> +
> +double a[10];
> +int f(int n){
> + a[3]=9;
> + __builtin_memset(&a[n],3,sizeof(double));
> + return a[3]==9;
> +}
> +
> +/* { dg-final { scan-tree-dump " == 9" "optimized" } } */
> +/* { dg-final { cleanup-tree-dump "optimized" } } */
>
> Property changes on: gcc/testsuite/gcc.dg/tree-ssa/pr58958.c
> ___________________________________________________________________
> Added: svn:keywords
> ## -0,0 +1 ##
> +Author Date Id Revision URL
> \ No newline at end of property
> Added: svn:eol-style
> ## -0,0 +1 ##
> +native
> \ No newline at end of property
> Index: gcc/tree-ssa-alias.c
> ===================================================================
> --- gcc/tree-ssa-alias.c (revision 204381)
> +++ gcc/tree-ssa-alias.c (working copy)
> @@ -559,41 +559,50 @@ ao_ref_alias_set (ao_ref *ref)
> }
>
> /* Init an alias-oracle reference representation from a gimple pointer
> PTR and a gimple size SIZE in bytes. If SIZE is NULL_TREE the the
> size is assumed to be unknown. The access is assumed to be only
> to or after of the pointer target, not before it. */
>
> void
> ao_ref_init_from_ptr_and_size (ao_ref *ref, tree ptr, tree size)
> {
> - HOST_WIDE_INT t1, t2, extra_offset = 0;
> + HOST_WIDE_INT t, extra_offset = 0;
> ref->ref = NULL_TREE;
> if (TREE_CODE (ptr) == SSA_NAME)
> {
> gimple stmt = SSA_NAME_DEF_STMT (ptr);
> if (gimple_assign_single_p (stmt)
> && gimple_assign_rhs_code (stmt) == ADDR_EXPR)
> ptr = gimple_assign_rhs1 (stmt);
> else if (is_gimple_assign (stmt)
> && gimple_assign_rhs_code (stmt) == POINTER_PLUS_EXPR
> && host_integerp (gimple_assign_rhs2 (stmt), 0)
> - && (t1 = int_cst_value (gimple_assign_rhs2 (stmt))) >= 0)
> + && (t = int_cst_value (gimple_assign_rhs2 (stmt))) >= 0)
> {
> ptr = gimple_assign_rhs1 (stmt);
> - extra_offset = BITS_PER_UNIT * t1;
> + extra_offset = BITS_PER_UNIT * t;
> }
> }
>
> if (TREE_CODE (ptr) == ADDR_EXPR)
> - ref->base = get_ref_base_and_extent (TREE_OPERAND (ptr, 0),
> - &ref->offset, &t1, &t2);
> + {
> + ref->base = get_addr_base_and_unit_offset (TREE_OPERAND (ptr, 0),
> &t);
> + if (ref->base)
> + ref->offset = BITS_PER_UNIT * t;
> + else
> + {
> + size = NULL_TREE;
> + ref->offset = 0;
> + ref->base = get_base_address (TREE_OPERAND (ptr, 0));
> + }
> + }
> else
> {
> ref->base = build2 (MEM_REF, char_type_node,
> ptr, null_pointer_node);
> ref->offset = 0;
> }
> ref->offset += extra_offset;
> if (size
> && host_integerp (size, 0)
> && TREE_INT_CST_LOW (size) * BITS_PER_UNIT / BITS_PER_UNIT
>