On Sat, Nov 9, 2013 at 12:18 AM, Marc Glisse <marc.gli...@inria.fr> wrote:
> On Wed, 6 Nov 2013, Richard Biener wrote:
>
>> So the only thing that remains is the mem_ref_offset thing and yes, I
>> guess
>> I'd prefer to use double-ints because we deal with bit offsets in the end.
>
>
> Here it is (bootstrap+testsuite on x86_64-unknown-linux-gnu). It feels
> rather artificial to do this small bit of computation with double_int
> when so much else assumes HWI is enough, but why not...
Ok.
Thanks,
Richard.
> 2013-11-09 Marc Glisse <marc.gli...@inria.fr>
>
> Jeff Law <l...@redhat.com>
>
> gcc/
> * tree-ssa-alias.c (stmt_kills_ref_p_1): Use
> ao_ref_init_from_ptr_and_size for builtins.
>
> gcc/testsuite/
> * gcc.dg/tree-ssa/alias-27.c: New testcase.
>
> --
> Marc Glisse
>
> Index: gcc/testsuite/gcc.dg/tree-ssa/alias-27.c
> ===================================================================
> --- gcc/testsuite/gcc.dg/tree-ssa/alias-27.c (revision 0)
> +++ gcc/testsuite/gcc.dg/tree-ssa/alias-27.c (working copy)
> @@ -0,0 +1,11 @@
> +/* { dg-do compile } */
> +/* { dg-options "-O1 -fdump-tree-optimized" } */
> +
> +void f (long *p) {
> + *p = 42;
> + p[4] = 42;
> + __builtin_memset (p, 0, 100);
> +}
> +
> +/* { dg-final { scan-tree-dump-not "= 42" "optimized" } } */
> +/* { dg-final { cleanup-tree-dump "optimized" } } */
>
> Property changes on: gcc/testsuite/gcc.dg/tree-ssa/alias-27.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 204608)
> +++ gcc/tree-ssa-alias.c (working copy)
> @@ -2001,23 +2001,24 @@ stmt_may_clobber_ref_p (gimple stmt, tre
> return stmt_may_clobber_ref_p_1 (stmt, &r);
> }
>
> /* If STMT kills the memory reference REF return true, otherwise
> return false. */
>
> static bool
> stmt_kills_ref_p_1 (gimple stmt, ao_ref *ref)
> {
> /* For a must-alias check we need to be able to constrain
> - the access properly. */
> - ao_ref_base (ref);
> - if (ref->max_size == -1)
> + the access properly.
> + FIXME: except for BUILTIN_FREE. */
> + if (!ao_ref_base (ref)
> + || ref->max_size == -1)
> return false;
>
> if (gimple_has_lhs (stmt)
> && TREE_CODE (gimple_get_lhs (stmt)) != SSA_NAME
> /* The assignment is not necessarily carried out if it can throw
> and we can catch it in the current function where we could inspect
> the previous value.
> ??? We only need to care about the RHS throwing. For aggregate
> assignments or similar calls and non-call exceptions the LHS
> might throw as well. */
> @@ -2090,37 +2091,47 @@ stmt_kills_ref_p_1 (gimple stmt, ao_ref
> case BUILT_IN_MEMPCPY:
> case BUILT_IN_MEMMOVE:
> case BUILT_IN_MEMSET:
> case BUILT_IN_MEMCPY_CHK:
> case BUILT_IN_MEMPCPY_CHK:
> case BUILT_IN_MEMMOVE_CHK:
> case BUILT_IN_MEMSET_CHK:
> {
> tree dest = gimple_call_arg (stmt, 0);
> tree len = gimple_call_arg (stmt, 2);
> - tree base = NULL_TREE;
> - HOST_WIDE_INT offset = 0;
> if (!host_integerp (len, 0))
> return false;
> - if (TREE_CODE (dest) == ADDR_EXPR)
> - base = get_addr_base_and_unit_offset (TREE_OPERAND (dest,
> 0),
> - &offset);
> - else if (TREE_CODE (dest) == SSA_NAME)
> - base = dest;
> - if (base
> - && base == ao_ref_base (ref))
> + tree rbase = ref->base;
> + double_int roffset = double_int::from_shwi (ref->offset);
> + ao_ref dref;
> + ao_ref_init_from_ptr_and_size (&dref, dest, len);
> + tree base = ao_ref_base (&dref);
> + double_int offset = double_int::from_shwi (dref.offset);
> + double_int bpu = double_int::from_uhwi (BITS_PER_UNIT);
> + if (!base || dref.size == -1)
> + return false;
> + if (TREE_CODE (base) == MEM_REF)
> + {
> + if (TREE_CODE (rbase) != MEM_REF)
> + return false;
> + // Compare pointers.
> + offset += bpu * mem_ref_offset (base);
> + roffset += bpu * mem_ref_offset (rbase);
> + base = TREE_OPERAND (base, 0);
> + rbase = TREE_OPERAND (rbase, 0);
> + }
> + if (base == rbase)
> {
> - HOST_WIDE_INT size = TREE_INT_CST_LOW (len);
> - if (offset <= ref->offset / BITS_PER_UNIT
> - && (offset + size
> - >= ((ref->offset + ref->max_size + BITS_PER_UNIT -
> 1)
> - / BITS_PER_UNIT)))
> + double_int size = bpu * tree_to_double_int (len);
> + double_int rsize = double_int::from_uhwi (ref->max_size);
> + if (offset.sle (roffset)
> + && (roffset + rsize).sle (offset + size))
> return true;
> }
> break;
> }
>
> case BUILT_IN_VA_END:
> {
> tree ptr = gimple_call_arg (stmt, 0);
> if (TREE_CODE (ptr) == ADDR_EXPR)
> {
>
