[Bug c/60937] New: -Os -fprofile-arcs breaks __attribute__((error()))

[Bug c/60937] New: -Os -fprofile-arcs breaks __attribute__((error()))

[kirill at shutemov dot name]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=60937

            Bug ID: 60937
           Summary: -Os -fprofile-arcs breaks __attribute__((error()))
           Product: gcc
           Version: 4.8.2
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c
          Assignee: unassigned at gcc dot gnu.org
          Reporter: kirill at shutemov dot name

Created attachment 32660
  --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=32660&action=edit
Reduced test case

Use of -Os and -fprofile-arcs break __attribute__((error())) behavior on
attached test case. It false-positively triggers compile time error:

$ gcc -Wall -Os -fprofile-arcs -c -o mm/.tmp_gup.o gup.i
gup.i: In function ‘__get_user_pages’:
gup.i:29:44: error: call to ‘__compiletime_assert’ declared with attribute
error: BUILD_BUG failed
                        __compiletime_assert();

Switching to other optimization level (above 0) or remove -fprofile-arcs does
not lead to that:

$ gcc -Wall -O1 -fprofile-arcs -c -o mm/.tmp_gup.o gup.i
$ gcc -Wall -Os -c -o mm/.tmp_gup.o gup.i
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From: "jamborm at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug ipa/60911] [4.9/4.10 Regression] wrong code with -O2 -flto -fipa-pta
Date: Wed, 23 Apr 2014 11:52:00 -0000
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http://gcc.gnu.org/bugzilla/show_bug.cgi?id`911

--- Comment #3 from Martin Jambor <jamborm at gcc dot gnu.org> ---
(In reply to Richard Biener from comment #2)
> Late IPA passes need all regular IPA transforms applied and clones
> materialized.

I agree that would make sense but it is not what we do.  Just look at
compile() in cgraphunit.c.  When late IPA passes run, clones are
already materialized but transformation phases of regular IPA passes
have not been run yet.  Apart from the fact that late-IPA passes do
not see the bodies transformed and inlining performed it also means
that call statements have not been updated to reflect call
redirections performed at analysis stage which is the problem here and
which is (for reasons I have never quite grasped) done as a part of
inlining transformation phase.

OTOH, I am all for moving the call to execute_all_ipa_transforms()
from expand_function() to compile(), at least in trunk.

[Bug middle-end/60937] -Os -fprofile-arcs breaks __attribute__((error()))

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=60937

Andrew Pinski <pinskia at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Keywords|                            |missed-optimization

--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Looks to be fixed on the trunk.
Where we can jump thread:
  <bb 4> [local count: 1073741824]:
  # _26 = PHI <0(2), -12(3)>
  PROF_edge_counter_8 = __gcov0._Z16__get_user_pagesv[1];
  PROF_edge_counter_9 = PROF_edge_counter_8 + 1;
  __gcov0._Z16__get_user_pagesv[1] = PROF_edge_counter_9;
  switch (_26) <default: <L9> [33.00%], case -133: <L8> [67.00%], case -12:
<L8> [67.00%], case 0: <L8> [67.00%]>

Now. as the switch only will goto L8 for the two values of _26.

[Bug middle-end/60937] -Os -fprofile-arcs breaks __attribute__((error()))

[marxin at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=60937

Martin Liška <marxin at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |aldyh at gcc dot gnu.org,
                   |                            |marxin at gcc dot gnu.org
           Keywords|needs-bisection             |
             Status|UNCONFIRMED                 |NEW
   Last reconfirmed|                            |2021-12-09
     Ever confirmed|0                           |1

--- Comment #2 from Martin Liška <marxin at gcc dot gnu.org> ---
Fixed with r12-324-g69e5544210e3c0e2.