Pattern recognition can leave stale STMT_VINFO_RELATED_STMT entries
around which confuses the correctness asserting I put into
get_{earlier,later}_stmt. The following makes sure to clear
those again. To make things more complicated pattern recognition
sometimes scans forward ... which runs into the issue that a later
attempt to detect a pattern might overwrite an earlier pattern.
The patch disallows that as well.
Bootstrapped and tested on x86_64-unknown-linux-gnu, applied to trunk.
I've just noticed a larger series from Richard S. and hope this
doesn't interfere.
Richard.
>From 3537753ed4924b2220b9dd51023edb6c0c5fc3b4 Mon Sep 17 00:00:00 2001
From: Richard Guenther <rguent...@suse.de>
Date: Mon, 18 Jun 2018 10:53:35 +0200
Subject: [PATCH] fix-pr86179
2018-06-19 Richard Biener <rguent...@suse.de>
PR tree-optimization/86179
* tree-vect-patterns.c (vect_pattern_recog_1): Clean up
after failed recognition.
* gcc.dg/pr86179.c: New testcase.
diff --git a/gcc/testsuite/gcc.dg/pr86179.c b/gcc/testsuite/gcc.dg/pr86179.c
new file mode 100644
index 00000000000..6a90f09e6e8
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/pr86179.c
@@ -0,0 +1,14 @@
+/* { dg-do compile } */
+/* { dg-options "-O3" } */
+
+void c(int *d, char *g)
+{
+ char *a, *b, *e;
+ int f;
+ for (; f; f -= 8) {
+ *d++ = *e++ | (unsigned)*g++ << 8 | (unsigned)*b++ << 16 |
+ (unsigned)*a++ << 24;
+ *d++ = *e++ | (unsigned)*g++ << 8 | (unsigned)*b++ << 16 |
+ (unsigned)*a++ << 24;
+ }
+}
diff --git a/gcc/tree-vect-patterns.c b/gcc/tree-vect-patterns.c
index 6621392b7e8..1eb3afa9542 100644
--- a/gcc/tree-vect-patterns.c
+++ b/gcc/tree-vect-patterns.c
@@ -4496,7 +4496,18 @@ vect_pattern_recog_1 (vect_recog_func *recog_func,
stmts_to_replace->quick_push (stmt);
pattern_stmt = recog_func->fn (stmts_to_replace, &type_in, &type_out);
if (!pattern_stmt)
- return false;
+ {
+ /* Clear related stmt info that analysis might have noted for
+ to be replaced stmts. */
+ for (i = 0; stmts_to_replace->iterate (i, &stmt)
+ && (unsigned) i < stmts_to_replace->length ();
+ i++)
+ {
+ stmt_info = vinfo_for_stmt (stmt);
+ STMT_VINFO_RELATED_STMT (stmt_info) = NULL;
+ }
+ return false;
+ }
stmt = stmts_to_replace->last ();
stmt_info = vinfo_for_stmt (stmt);
@@ -4668,7 +4679,6 @@ vect_pattern_recog (vec_info *vinfo)
gimple_stmt_iterator si;
unsigned int i, j;
auto_vec<gimple *, 1> stmts_to_replace;
- gimple *stmt;
if (dump_enabled_p ())
dump_printf_loc (MSG_NOTE, vect_location,
@@ -4687,6 +4697,10 @@ vect_pattern_recog (vec_info *vinfo)
basic_block bb = bbs[i];
for (si = gsi_start_bb (bb); !gsi_end_p (si); gsi_next (&si))
{
+ gimple *stmt = gsi_stmt (si);
+ stmt_vec_info stmt_info = vinfo_for_stmt (stmt);
+ if (stmt_info && STMT_VINFO_IN_PATTERN_P (stmt_info))
+ continue;
/* Scan over all generic vect_recog_xxx_pattern functions. */
for (j = 0; j < NUM_PATTERNS; j++)
if (vect_pattern_recog_1 (&vect_vect_recog_func_ptrs[j], si,
@@ -4701,9 +4715,11 @@ vect_pattern_recog (vec_info *vinfo)
for (si = bb_vinfo->region_begin;
gsi_stmt (si) != gsi_stmt (bb_vinfo->region_end); gsi_next (&si))
{
- if ((stmt = gsi_stmt (si))
- && vinfo_for_stmt (stmt)
- && !STMT_VINFO_VECTORIZABLE (vinfo_for_stmt (stmt)))
+ gimple *stmt = gsi_stmt (si);
+ stmt_vec_info stmt_info = vinfo_for_stmt (stmt);
+ if (stmt_info
+ && (!STMT_VINFO_VECTORIZABLE (stmt_info)
+ || STMT_VINFO_IN_PATTERN_P (stmt_info)))
continue;
/* Scan over all generic vect_recog_xxx_pattern functions. */
