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tree-optimization/113863 - elide degenerate virtual PHIs when moving ee stores

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This makes sure to elide degenerate virtual PHIs when moving stores
across early exits.

	PR tree-optimization/113863
	* tree-vect-data-refs.cc (vect_analyze_early_break_dependences):
	Record crossed virtual PHIs.
	* tree-vect-loop.cc (move_early_exit_stmts): Elide crossed
	virtual PHIs.

	* gcc.dg/vect/pr113863.c: New testcase.
This commit is contained in:
Richard Biener 2024-02-12 10:40:42 +01:00
parent cc136a0bdc
commit 1e3f78dbb3
3 changed files with 40 additions and 0 deletions
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17
gcc/testsuite/gcc.dg/vect/pr113863.c Normal file
View file

@ -0,0 +1,17 @@
/* { dg-do compile } */
/* { dg-add-options vect_early_break } */
/* { dg-additional-options "-O3" } */
void test_sort_helper(int *);
int test_sort_driver_driver_real_last;
void test_sort_driver_driver(int start, int *e, int *f)
{
for (int *l = e; l > f;)
{
*--l = start;
if (f == l)
test_sort_helper(&test_sort_driver_driver_real_last);
if (start)
test_sort_driver_driver(start - 1, e, f);
}
}

4
gcc/tree-vect-data-refs.cc
View file

@ -812,6 +812,10 @@ vect_analyze_early_break_dependences (loop_vec_info loop_vinfo)
break;
}
/* If we possibly sink through a virtual PHI make sure to elide that. */
if (gphi *vphi = get_virtual_phi (bb))
LOOP_VINFO_EARLY_BRK_STORES (loop_vinfo).safe_push (vphi);
/* All earlier blocks need dependence checking. */
check_deps = true;
bb = single_pred (bb);

19
gcc/tree-vect-loop.cc
View file

@ -11789,6 +11789,25 @@ move_early_exit_stmts (loop_vec_info loop_vinfo)
for (gimple *stmt : LOOP_VINFO_EARLY_BRK_STORES (loop_vinfo))
{
/* We have to update crossed degenerate virtual PHIs. Simply
elide them. */
if (gphi *vphi = dyn_cast <gphi *> (stmt))
{
tree vdef = gimple_phi_result (vphi);
tree vuse = gimple_phi_arg_def (vphi, 0);
imm_use_iterator iter;
use_operand_p use_p;
gimple *use_stmt;
FOR_EACH_IMM_USE_STMT (use_stmt, iter, vdef)
{
FOR_EACH_IMM_USE_ON_STMT (use_p, iter)
SET_USE (use_p, vuse);
}
auto gsi = gsi_for_stmt (stmt);
remove_phi_node (&gsi, true);
continue;
}
/* Check to see if statement is still required for vect or has been
elided. */
auto stmt_info = loop_vinfo->lookup_stmt (stmt);