On Thu, 11 Jul 2019, Jan Hubicka wrote:
> Hi,
> this patch makes nonoverlapping_component_refs_since_match_p to accept
> paths with non-trivial MEM_REFs and TMRs assuming that they have same
> semantics.
Hmm. We'll never get any TARGET_MEM_REFs wrapped with
handled-components so I wonder if it makes sense to handle it in
nonoverlapping_component_refs_since_match_p at all.
> Bootstrapped/regtested x86_64-linux, OK?
>
> Honza
>
> * tree-ssa-alias.c (same_tmr_indexing_p): Break out from ...
> (indirect_refs_may_alias_p): ... here.
> (nonoverlapping_component_refs_since_match_p): Support also non-trivial
> mem refs in the access paths.
> Index: testsuite/gcc.dg/tree-ssa/alias-access-path-9.c
> ===================================================================
> --- testsuite/gcc.dg/tree-ssa/alias-access-path-9.c (nonexistent)
> +++ testsuite/gcc.dg/tree-ssa/alias-access-path-9.c (working copy)
> @@ -0,0 +1,44 @@
> +/* { dg-do compile } */
> +/* { dg-options "-O2 -fdump-tree-fre1" } */
> +
> +/* This testcase tests nonoverlapping_component_refs_since_match_p in
> presence
> + of non-trivial mem-refs. */
> +struct a {int a,b;};
> +struct b {struct a a[10];};
> +struct c {int c; struct b b;} c, *cptr;
> +
> +void
> +set_a(struct a *a, int p)
> +{
> + a->a=p;
> +}
> +void
> +set_b(struct a *a, int p)
> +{
> + a->b=p;
> +}
> +int
> +get_a(struct a *a)
> +{
> + return a->a;
> +}
> +
> +int
> +test(int i, int j)
> +{
> + struct b *bptr = &c.b;
> + set_a (&bptr->a[i], 123);
> + set_b (&bptr->a[j], 124);
> + return get_a (&bptr->a[i]);
> +}
> +
> +int
> +test2(int i, int j)
> +{
> + struct b *bptr = &cptr->b;
> + set_a (&bptr->a[i], 125);
> + set_b (&bptr->a[j], 126);
> + return get_a (&bptr->a[i]);
> +}
> +/* { dg-final { scan-tree-dump-times "return 123" 1 "fre1"} } */
> +/* { dg-final { scan-tree-dump-times "return 125" 1 "fre1"} } */
> Index: tree-ssa-alias.c
> ===================================================================
> --- tree-ssa-alias.c (revision 273322)
> +++ tree-ssa-alias.c (working copy)
> @@ -1216,6 +1216,25 @@ nonoverlapping_component_refs_p_1 (const
> return -1;
> }
>
> +/* Return if TARGET_MEM_REFS base1 and base2 have same offsets. */
> +
> +static bool
> +same_tmr_indexing_p (tree base1, tree base2)
> +{
> + return ((TMR_STEP (base1) == TMR_STEP (base2)
> + || (TMR_STEP (base1) && TMR_STEP (base2)
> + && operand_equal_p (TMR_STEP (base1),
> + TMR_STEP (base2), 0)))
> + && (TMR_INDEX (base1) == TMR_INDEX (base2)
> + || (TMR_INDEX (base1) && TMR_INDEX (base2)
> + && operand_equal_p (TMR_INDEX (base1),
> + TMR_INDEX (base2), 0)))
> + && (TMR_INDEX2 (base1) == TMR_INDEX2 (base2)
> + || (TMR_INDEX2 (base1) && TMR_INDEX2 (base2)
> + && operand_equal_p (TMR_INDEX2 (base1),
> + TMR_INDEX2 (base2), 0))));
> +}
> +
> /* Try to disambiguate REF1 and REF2 under the assumption that MATCH1 and
> MATCH2 either point to the same address or are disjoint.
> MATCH1 and MATCH2 are assumed to be ref in the access path of REF1 and
> REF2
> @@ -1265,20 +1284,6 @@ nonoverlapping_component_refs_since_matc
> component_refs1.safe_push (ref1);
> ref1 = TREE_OPERAND (ref1, 0);
> }
> - if (TREE_CODE (ref1) == MEM_REF && ref1 != match1)
> - {
> - if (!integer_zerop (TREE_OPERAND (ref1, 1)))
> - {
> - ++alias_stats.nonoverlapping_component_refs_since_match_p_may_alias;
> - return -1;
> - }
> - }
> - /* TODO: Handle TARGET_MEM_REF later. */
> - if (TREE_CODE (ref1) == TARGET_MEM_REF && ref1 != match1)
> - {
> - ++alias_stats.nonoverlapping_component_refs_since_match_p_may_alias;
> - return -1;
> - }
>
> /* Create the stack of handled components for REF2. */
> while (handled_component_p (ref2) && ref2 != match2)
> @@ -1290,15 +1295,39 @@ nonoverlapping_component_refs_since_matc
> component_refs2.safe_push (ref2);
> ref2 = TREE_OPERAND (ref2, 0);
> }
> - if (TREE_CODE (ref2) == MEM_REF && ref2 != match2)
> +
> + bool mem_ref1 = TREE_CODE (ref1) == MEM_REF && ref1 != match1;
> + bool mem_ref2 = TREE_CODE (ref2) == MEM_REF && ref2 != match2;
> +
> + /* If only one of access path starts with MEM_REF check that offset is 0
> + so the addresses stays the same after stripping it.
> + TODO: In this case we may walk the other access path until we get same
> + offset.
> +
> + If both starts with MEM_REF, offset has to be same. */
> + if ((mem_ref1 && !mem_ref2 && !integer_zerop (TREE_OPERAND (ref1, 1)))
> + || (mem_ref2 && !mem_ref1 && !integer_zerop (TREE_OPERAND (ref2, 1)))
> + || (mem_ref1 && mem_ref2
> + && !tree_int_cst_equal (TREE_OPERAND (ref1, 1),
> + TREE_OPERAND (ref2, 1))))
> {
> - if (!integer_zerop (TREE_OPERAND (ref2, 1)))
> - {
> - ++alias_stats.nonoverlapping_component_refs_since_match_p_may_alias;
> - return -1;
> - }
> + ++alias_stats.nonoverlapping_component_refs_since_match_p_may_alias;
> + return -1;
> }
> - if (TREE_CODE (ref2) == TARGET_MEM_REF && ref2 != match2)
> +
> + bool target_mem_ref1 = TREE_CODE (ref1) == TARGET_MEM_REF && ref1 !=
> match1;
> + bool target_mem_ref2 = TREE_CODE (ref2) == TARGET_MEM_REF && ref2 !=
> match2;
> +
> + if ((target_mem_ref1 && !target_mem_ref2
> + && (TMR_INDEX (ref1) || TMR_INDEX2 (ref1)
> + || !integer_zerop (TREE_OPERAND (ref1, 1))))
> + || (target_mem_ref2 && !target_mem_ref1
> + && (TMR_INDEX (ref2) || TMR_INDEX2 (ref2)
> + || !integer_zerop (TREE_OPERAND (ref2, 1))))
> + || (target_mem_ref1 && target_mem_ref2
> + && (!same_tmr_indexing_p (ref1, ref2)
> + || !tree_int_cst_equal (TREE_OPERAND (ref1, 1),
> + TREE_OPERAND (ref2, 1)))))
> {
> ++alias_stats.nonoverlapping_component_refs_since_match_p_may_alias;
> return -1;
> @@ -1776,18 +1805,7 @@ indirect_refs_may_alias_p (tree ref1 ATT
> || (!TMR_INDEX (base2) && !TMR_INDEX2 (base2))))
> || (TREE_CODE (base1) == TARGET_MEM_REF
> && TREE_CODE (base2) == TARGET_MEM_REF
> - && (TMR_STEP (base1) == TMR_STEP (base2)
> - || (TMR_STEP (base1) && TMR_STEP (base2)
> - && operand_equal_p (TMR_STEP (base1),
> - TMR_STEP (base2), 0)))
> - && (TMR_INDEX (base1) == TMR_INDEX (base2)
> - || (TMR_INDEX (base1) && TMR_INDEX (base2)
> - && operand_equal_p (TMR_INDEX (base1),
> - TMR_INDEX (base2), 0)))
> - && (TMR_INDEX2 (base1) == TMR_INDEX2 (base2)
> - || (TMR_INDEX2 (base1) && TMR_INDEX2 (base2)
> - && operand_equal_p (TMR_INDEX2 (base1),
> - TMR_INDEX2 (base2), 0))))))
> + && same_tmr_indexing_p (base1, base2))))
> {
> poly_offset_int moff1 = mem_ref_offset (base1) << LOG2_BITS_PER_UNIT;
> poly_offset_int moff2 = mem_ref_offset (base2) << LOG2_BITS_PER_UNIT;
>
--
Richard Biener <[email protected]>
SUSE Linux GmbH, Maxfeldstrasse 5, 90409 Nuernberg, Germany;
GF: Felix Imendörffer, Mary Higgins, Sri Rasiah; HRB 21284 (AG Nürnberg)
