This is the mail archive of the
gcc-patches@gcc.gnu.org
mailing list for the GCC project.
[RFC] Fix context-sensitiveness of peephole2 pass
- From: Eric Botcazou <ebotcazou at adacore dot com>
- To: gcc-patches at gcc dot gnu dot org
- Date: Thu, 24 Oct 2013 23:10:55 +0200
- Subject: [RFC] Fix context-sensitiveness of peephole2 pass
- Authentication-results: sourceware.org; auth=none
As discovered by Richard B. under PR rtl-optimization/58831, the peephole2
pass has been context-sensitive for a long time when scratch registers are
needed, in the sense that the behaviour of the pass for a given function is
dependent on what happened for the previously optimized function.
Obvious patch attached, tested on x86_64-suse-linux. Do we want to apply it
on mainline only or on all the active branches?
2013-10-24 Eric Botcazou <ebotcazou@adacore.com>
* recog.c (search_ofs): New static variable moved from...
(peep2_find_free_register): ...here.
(peephole2_optimize): Initialize it.
--
Eric Botcazou
Index: recog.c
===================================================================
--- recog.c (revision 203876)
+++ recog.c (working copy)
@@ -3068,6 +3068,9 @@ peep2_reg_dead_p (int ofs, rtx reg)
return 1;
}
+/* Regno offset to be used in the register search. */
+static int search_ofs;
+
/* Try to find a hard register of mode MODE, matching the register class in
CLASS_STR, which is available at the beginning of insn CURRENT_INSN and
remains available until the end of LAST_INSN. LAST_INSN may be NULL_RTX,
@@ -3083,7 +3086,6 @@ rtx
peep2_find_free_register (int from, int to, const char *class_str,
enum machine_mode mode, HARD_REG_SET *reg_set)
{
- static int search_ofs;
enum reg_class cl;
HARD_REG_SET live;
df_ref *def_rec;
@@ -3548,6 +3550,7 @@ peephole2_optimize (void)
/* Initialize the regsets we're going to use. */
for (i = 0; i < MAX_INSNS_PER_PEEP2 + 1; ++i)
peep2_insn_data[i].live_before = BITMAP_ALLOC (®_obstack);
+ search_ofs = 0;
live = BITMAP_ALLOC (®_obstack);
FOR_EACH_BB_REVERSE (bb)