===================================================================
@@ -971,14 +971,23 @@ process_bb_lives (basic_block bb, int &c
live_pseudos_num++;
if (! sparseset_bit_p (pseudos_live, j))
{
- live_change_p = TRUE;
+ live_change_p = true;
+ if (lra_dump_file != NULL)
+ fprintf (lra_dump_file,
+ " r%d is removed as live at bb%d start\n", j, bb->index);
break;
}
}
- live_change_p
- = (live_change_p
- || sparseset_cardinality (pseudos_live) != live_pseudos_num);
-
+ if (! live_change_p
+ && sparseset_cardinality (pseudos_live) != live_pseudos_num)
+ {
+ live_change_p = true;
+ if (lra_dump_file != NULL)
+ EXECUTE_IF_SET_IN_SPARSESET (pseudos_live, j)
+ if (! bitmap_bit_p (df_get_live_in (bb), j))
+ fprintf (lra_dump_file,
+ " r%d is added to live at bb%d start\n", j, bb->index);
+ }
/* See if we'll need an increment at the end of this basic block.
An increment is needed if the PSEUDOS_LIVE set is not empty,
to make sure the finish points are set up correctly. */
@@ -1322,11 +1331,16 @@ lra_create_live_ranges (bool all_p, bool
if (lra_dump_file != NULL)
fprintf (lra_dump_file, "Live info was changed -- recalculate it\n");
/* Live info was changed on a bb border. It means that some info,
- e.g. about conflict regs, calls crossed may be wrong, live
- ranges. We need this info for allocation. So recalcualate it
- again. */
+ e.g. about conflict regs, calls crossed, and live ranges may be
+ wrong. We need this info for allocation. So recalculate it
+ again but without removing dead insns which can change live info
+ again. Repetitive live range calculations are expensive therefore
+ we stop here as we already have correct info although some
+ improvement in rare cases could be possible on this sub-pass if
+ we do dead insn elimination again (still the improvement may
+ happen later). */
lra_clear_live_ranges ();
- bool res = lra_create_live_ranges_1 (all_p, dead_insn_p);
+ bool res = lra_create_live_ranges_1 (all_p, false);
lra_assert (! res);
}
===================================================================
@@ -0,0 +1,35 @@
+/* PR rtl-optimization/64087 */
+/* { dg-do compile } */
+/* { dg-options "-O3" } */
+
+int printf (const char *, ...);
+
+int a[72], b, c, d, e;
+
+int
+main ()
+{
+ int h;
+ for (b = 0; b < 72; b++)
+ {
+ h = 1;
+ if (b)
+ h >>= 1;
+ a[b] = h;
+ }
+ for (; e; e++)
+ for (c = 0; c < 1;)
+ for (; d;)
+ {
+ printf ("0");
+ int g;
+ for (b = 0; b < 72; b++)
+ {
+ g = 1;
+ if (b)
+ g >>= 1;
+ a[b] = g;
+ }
+ }
+ return 0;
+}
The following patch fixes https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64087 The patch was bootstrapped and tested on x86-64. Committed as rev. 218162. 2014-11-28 Vladimir Makarov <vmakarov@redhat.com> PR rtl-optimization/64087 * lra-lives.c (process_bb_lives): Add debug output. (lra_create_live_ranges): Don't remove dead insn on the second call of lra_create_live_ranges_1. 2014-11-28 Vladimir Makarov <vmakarov@redhat.com> PR rtl-optimization/64087 * gcc.dg/pr64087.c: New.