Patchwork Fix PR tree-optimization/57322

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Submitter Easwaran Raman
Date May 19, 2013, 11:41 p.m.
Message ID <CAPK5YPbgHhyMvAC-o=5M1PSppj_d+G_Z0v5eDm_abaE9j9q34A@mail.gmail.com>
Download mbox | patch
Permalink /patch/244829/
State New
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Comments

Easwaran Raman - May 19, 2013, 11:41 p.m.
The UID of a newly generated statement in build_and_add_sum is set to
that of an adjacent statement in the BB. This is a problem in one case
where the BB is empty. This fix sets the UID to be 1 if the BB is
empty. Bootstraps and no test regressions on x86_64 . OK for trunk?

Thanks,
Easwaran

-----------

2013-05-19   Easwaran Raman  <eraman@google.com>

        PR tree-optimization/57322
        * (build_and_add_sum): If a BB is empty, set the UID of the statement
        added to the BB to be 1.
Steven Bosscher - May 20, 2013, 11:43 a.m.
On Mon, May 20, 2013 at 1:41 AM, Easwaran Raman <eraman@google.com> wrote:
>         PR tree-optimization/57322
>         * (build_and_add_sum): If a BB is empty, set the UID of the statement
>         added to the BB to be 1.

Maybe  "gimple_set_uid (stmt, inc_gimple_stmt_max_uid (cfun));"? That
would keep the UIDs unique except for the copied UIDs.

Ciao!
Steven
Easwaran Raman - May 20, 2013, 2 p.m.
If you are suggesting using inc_gimple_stmt_max_uid(cfun) for all
statements, that won't work because we want to use the UIDs to
determine dominance within a BB. If your suggestion is to use that
instead of 1 when BB == NULL, that would work (even though setting it
to 1 is sufficient.)

Thanks,
Easwaran


On Mon, May 20, 2013 at 4:43 AM, Steven Bosscher <stevenb.gcc@gmail.com> wrote:
> On Mon, May 20, 2013 at 1:41 AM, Easwaran Raman <eraman@google.com> wrote:
>>         PR tree-optimization/57322
>>         * (build_and_add_sum): If a BB is empty, set the UID of the statement
>>         added to the BB to be 1.
>
> Maybe  "gimple_set_uid (stmt, inc_gimple_stmt_max_uid (cfun));"? That
> would keep the UIDs unique except for the copied UIDs.
>
> Ciao!
> Steven
Steven Bosscher - May 20, 2013, 2:04 p.m.
On Mon, May 20, 2013 at 4:00 PM, Easwaran Raman wrote:
> If your suggestion is to use that
> instead of 1 when BB == NULL, that would work (even though setting it
> to 1 is sufficient.)

That's what I suggest, yes. I understand that 1 is sufficient for now,
but you never know if/when someone will use these uids for something
else within the pass and expect them to be more-or-less unique (only
non-unique for consecutive insns).

But I have no strong preference either way, 1 or max+1.

Ciao!
Steven
Richard Guenther - May 21, 2013, 8:33 a.m.
On Mon, May 20, 2013 at 4:04 PM, Steven Bosscher <stevenb.gcc@gmail.com> wrote:
> On Mon, May 20, 2013 at 4:00 PM, Easwaran Raman wrote:
>> If your suggestion is to use that
>> instead of 1 when BB == NULL, that would work (even though setting it
>> to 1 is sufficient.)
>
> That's what I suggest, yes. I understand that 1 is sufficient for now,
> but you never know if/when someone will use these uids for something
> else within the pass and expect them to be more-or-less unique (only
> non-unique for consecutive insns).
>
> But I have no strong preference either way, 1 or max+1.

It has to be 1 for correctness reason.

The patch is ok with the testcase included.

Thanks,
Richard.

> Ciao!
> Steven
Eric Botcazou - May 24, 2013, 8:06 a.m.
> 2013-05-19   Easwaran Raman  <eraman@google.com>
> 
>         PR tree-optimization/57322
>         * (build_and_add_sum): If a BB is empty, set the UID of the
> statement added to the BB to be 1.

Missing filename in the ChangeLog.

Patch

Index: gcc/tree-ssa-reassoc.c
===================================================================
--- gcc/tree-ssa-reassoc.c      (revision 199048)
+++ gcc/tree-ssa-reassoc.c      (working copy)
@@ -1165,8 +1165,12 @@  build_and_add_sum (tree type, tree op1, tree op2,
   if ((!op1def || gimple_nop_p (op1def))
       && (!op2def || gimple_nop_p (op2def)))
     {
+      gimple first_stmt;
+      unsigned uid;
       gsi = gsi_after_labels (single_succ (ENTRY_BLOCK_PTR));
-      gimple_set_uid (sum, gimple_uid (gsi_stmt (gsi)));
+      first_stmt = gsi_stmt (gsi);
+      uid = first_stmt ? gimple_uid (first_stmt) : 1;
+      gimple_set_uid (sum, uid);
       gsi_insert_before (&gsi, sum, GSI_NEW_STMT);
     }
   else if ((!op1def || gimple_nop_p (op1def))