Hi!
This bug has been introduced recently, we shouldn't take debug uses into
account when deciding whether to optimize.
Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?
2011-06-22 Jakub Jelinek <ja...@redhat.com>
PR debug/49496
* tree-vect-patterns.c (vect_recog_widen_mult_pattern): Ignore debug
uses.
* gcc.dg/pr49496.c: New test.
--- gcc/tree-vect-patterns.c.jj 2011-06-17 11:02:19.000000000 +0200
+++ gcc/tree-vect-patterns.c 2011-06-22 11:23:08.000000000 +0200
@@ -557,6 +557,8 @@ vect_recog_widen_mult_pattern (VEC (gimp
FOR_EACH_IMM_USE_FAST (use_p, imm_iter, lhs)
{
+ if (is_gimple_debug (USE_STMT (use_p)))
+ continue;
use_stmt = USE_STMT (use_p);
nuses++;
}
--- gcc/testsuite/gcc.dg/pr49496.c.jj 2011-06-22 11:24:30.000000000 +0200
+++ gcc/testsuite/gcc.dg/pr49496.c 2011-06-22 11:28:33.000000000 +0200
@@ -0,0 +1,20 @@
+/* PR debug/49496 */
+/* { dg-do compile } */
+/* { dg-options "-O3 -fcompare-debug" } */
+
+unsigned short u[8], s1[8], s2[8];
+
+void bar (unsigned short *);
+
+void
+foo (void)
+{
+ unsigned short e[8];
+ int i;
+ for (i = 0; i < 8; i++)
+ {
+ int tmp = s1[i] * s2[i];
+ e[i] = (tmp & 0xffff0000) >> 16;
+ }
+ bar (e);
+}
Jakub
