Patchwork [v2,haifa-sched] : Fix PR56023, -fcompare-debug failure due to sched1 pass on 4.6 branch

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Submitter Uros Bizjak
Date Jan. 21, 2013, 12:27 p.m.
Message ID <CAFULd4ZBjrjUF6fdV_VNiV5DhmMS7w524of3DO8qy=6hvdKuyQ@mail.gmail.com>
Download mbox | patch
Permalink /patch/214127/
State New
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Comments

Uros Bizjak - Jan. 21, 2013, 12:27 p.m.
On Sat, Jan 19, 2013 at 8:57 PM, Uros Bizjak <ubizjak@gmail.com> wrote:

> We should not update ticks of instructions, dependent on debug
> instruction. Without the patch, the scheduling order depends on the
> presence of debug instructions and leads to -fcompare-debug failures.

Attached patch refines previous patch to reject only cases where
non-debug insns depend on debug instructions. We can still fix
inter-ticks of dependent debug insns, without affecting emitted
real-insn sequences.

2012-01-21  Uros Bizjak  <ubizjak@gmail.com>

        PR rtl-optimization/56023
        * haifa-sched.c (fix_inter_tick): Do not update ticks of non-debug
        instructions, dependent on debug instruction.

testsuite/ChangeLog:

2012-01-21  Uros Bizjak  <ubizjak@gmail.com>

        PR rtl-optimization/56023
        * gcc.dg/pr56023.c: New test.


Re-tested on 4.6 branch on alpha-linux-gnu, where it fixes the
bootstrap failure and on x86_64-pc-linux-gnu {,-m32}.

The patch should be applied to 4.7 and 4.8 branches as well. Patch was
also re-tested on mainline x86_64-pc-linux-gnu {,-m32}.

OK for 4.6, 4.7 and mainline?

Uros.
Uros Bizjak - Jan. 21, 2013, 5:37 p.m.
On Mon, Jan 21, 2013 at 1:27 PM, Uros Bizjak <ubizjak@gmail.com> wrote:

>> We should not update ticks of instructions, dependent on debug
>> instruction. Without the patch, the scheduling order depends on the
>> presence of debug instructions and leads to -fcompare-debug failures.
>
> Attached patch refines previous patch to reject only cases where
> non-debug insns depend on debug instructions. We can still fix
> inter-ticks of dependent debug insns, without affecting emitted
> real-insn sequences.

FTR, from offline discussion with Vlad, setting ticks of debug
instructions is not necessary (and just wastes cycles), so I will
commit version 1 of the patch.

Uros.

Patch

Index: haifa-sched.c
===================================================================
--- haifa-sched.c	(revision 195330)
+++ haifa-sched.c	(working copy)
@@ -3686,9 +3686,11 @@  fix_inter_tick (rtx head, rtx tail)
 
 	  FOR_EACH_DEP (head, SD_LIST_RES_FORW, sd_it, dep)
 	    {
-	      rtx next;
+	      rtx next = DEP_CON (dep);
 
-	      next = DEP_CON (dep);
+	      if (DEBUG_INSN_P (head) && !DEBUG_INSN_P (next))
+		continue;
+
 	      tick = INSN_TICK (next);
 
 	      if (tick != INVALID_TICK