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tree-optimization/93381 fix integer offsetting in points-to analysis

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We were incorrectly assuming a merge operation is conservative enough
for not explicitely handled operations but we also need to consider
offsetting within fields when field-sensitive analysis applies.

2020-01-22  Richard Biener  <rguenther@suse.de>

	PR tree-optimization/93381
	* tree-ssa-structalias.c (find_func_aliases): Assume offsetting
	throughout, handle all conversions the same.

	* gcc.dg/torture/pr93381.c: New testcase.
This commit is contained in:
Richard Biener 2020-01-22 12:38:12 +01:00
parent d80f0a8dc9
commit 2b85c08822
4 changed files with 46 additions and 7 deletions
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6
gcc/ChangeLog
View file

@ -1,3 +1,9 @@
2020-01-22 Richard Biener <rguenther@suse.de>
PR tree-optimization/93381
* tree-ssa-structalias.c (find_func_aliases): Assume offsetting
throughout, handle all conversions the same.
2020-01-22 Jakub Jelinek <jakub@redhat.com>
PR target/93335

5
gcc/testsuite/ChangeLog
View file

@ -1,3 +1,8 @@
2020-01-22 Richard Biener <rguenther@suse.de>
PR tree-optimization/93381
* gcc.dg/torture/pr93381.c: New testcase.
2020-01-22 Jakub Jelinek <jakub@redhat.com>
PR target/93335

25
gcc/testsuite/gcc.dg/torture/pr93381.c Normal file
View file

@ -0,0 +1,25 @@
/* { dg-do run } */
static struct S { int *p1; int *p2; } s;
typedef __UINTPTR_TYPE__ uintptr_t;
int foo()
{
int i = 1, j = 2;
struct S s;
int **p;
s.p1 = &i;
s.p2 = &j;
p = &s.p1;
uintptr_t pi = (uintptr_t)p;
pi = pi + sizeof (int *);
p = (int **)pi;
**p = 3;
return j;
}
int main()
{
if (foo () != 3)
__builtin_abort ();
return 0;
}

17
gcc/tree-ssa-structalias.c
View file

@ -5008,11 +5008,12 @@ find_func_aliases (struct function *fn, gimple *origt)
|| code == FLOOR_MOD_EXPR
|| code == ROUND_MOD_EXPR)
/* Division and modulo transfer the pointer from the LHS. */
get_constraint_for_rhs (gimple_assign_rhs1 (t), &rhsc);
else if ((CONVERT_EXPR_CODE_P (code)
&& !(POINTER_TYPE_P (gimple_expr_type (t))
&& !POINTER_TYPE_P (TREE_TYPE (rhsop))))
get_constraint_for_ptr_offset (gimple_assign_rhs1 (t),
NULL_TREE, &rhsc);
else if (CONVERT_EXPR_CODE_P (code)
|| gimple_assign_single_p (t))
/* See through conversions, single RHS are handled by
get_constraint_for_rhs. */
get_constraint_for_rhs (rhsop, &rhsc);
else if (code == COND_EXPR)
{
@ -5031,14 +5032,16 @@ find_func_aliases (struct function *fn, gimple *origt)
;
else
{
/* All other operations are merges. */
/* All other operations are possibly offsetting merges. */
auto_vec<ce_s, 4> tmp;
struct constraint_expr *rhsp;
unsigned i, j;
get_constraint_for_rhs (gimple_assign_rhs1 (t), &rhsc);
get_constraint_for_ptr_offset (gimple_assign_rhs1 (t),
NULL_TREE, &rhsc);
for (i = 2; i < gimple_num_ops (t); ++i)
{
get_constraint_for_rhs (gimple_op (t, i), &tmp);
get_constraint_for_ptr_offset (gimple_op (t, i),
NULL_TREE, &tmp);
FOR_EACH_VEC_ELT (tmp, j, rhsp)
rhsc.safe_push (*rhsp);
tmp.truncate (0);