[Bug target/51793] New: pragma GCC optimize wrapv leads to invalid code on Solaris

[Bug target/51793] New: pragma GCC optimize wrapv leads to invalid code on Solaris

[bruno at clisp dot org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=51793

             Bug #: 51793
           Summary: pragma GCC optimize wrapv leads to invalid code on
                    Solaris
    Classification: Unclassified
           Product: gcc
           Version: 4.5.2
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: target
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: bruno@clisp.org


Created attachment 26274
  --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=26274
Test case

The use of
#pragma GCC optimize ("wrapv")
with optimization level -O2 turns the ".p2align 4,,15" to ".p2align 4,,-1".
This can be observed on both i386-pc-solaris2.11 and i386-pc-linux-gnu systems.
On i386-pc-solaris2.11 it causes a compilation failure, because the assembler
does not understand this syntax.

How to reproduce:
================================== foo.c ==================================
#pragma GCC optimize ("wrapv")
int foo () { return 17; }
int bar () { return 42; }
===========================================================================


$ gcc -O2 -c foo.c
Assembler: foo.c
    "/var/tmp//ccwQaWQO.s", line 3 : .align test amount has negative value
    "/var/tmp//ccwQaWQO.s", line 10 : .align test amount has negative value

$ gcc -O2 -S foo.c

$ cat foo.s
    .file    "foo.c"
    .text
    .p2align 4,,-1
.globl foo
    .type    foo, @function
foo:
    movl    $17, %eax
    ret
    .size    foo, .-foo
    .p2align 4,,-1
.globl bar
    .type    bar, @function
bar:
    movl    $42, %eax
    ret
    .size    bar, .-bar
    .ident    "GCC: (GNU) 4.5.2"


$ gcc --version
gcc (GCC) 4.5.2
Copyright (C) 2010 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.


$ gcc -v
Using built-in specs.
COLLECT_GCC=gcc
COLLECT_LTO_WRAPPER=/usr/gcc/4.5/lib/gcc/i386-pc-solaris2.11/4.5.2/lto-wrapper
Target: i386-pc-solaris2.11
Configured with:
/builds/hudson/workspace/nightly/build/i386/components/gcc45/gcc-4.5.2/configure
CC=/ws/onnv-tools/SUNWspro/sunstudio12.1/bin/cc
CXX=/ws/onnv-tools/SUNWspro/sunstudio12.1/bin/CC --prefix=/usr/gcc/4.5
--mandir=/usr/gcc/4.5/share/man --bindir=/usr/gcc/4.5/bin
--libdir=/usr/gcc/4.5/lib --sbindir=/usr/gcc/4.5/sbin
--enable-languages=c,c++,fortran,objc --enable-shared
--with-gmp-include=/usr/include/gmp --with-mpfr-include=/usr/include/mpfr
--prefix=/usr/gcc/4.5 --mandir=/usr/gcc/4.5/share/man
--infodir=/usr/gcc/4.5/share/info --libexecdir=/usr/gcc/4.5/lib CFLAGS='-g -O2
'
Thread model: posix
gcc version 4.5.2 (GCC) 


$ type as
as is hashed (/usr/bin/as)

$ as -V
as: Sun Compiler Common 12 SunOS_i386 snv_174 08/25/2011
Usage: as [-V] [-Q{y,n}] [-s]
      [-S[aAbBcClL]] [-K {pic,PIC}] [-o objfile] [-L] [-T]
      [-P [[-Ipath] [-Dname] [-Dname=def] [-Uname]]...]
      [-m [-Ym,path]] [-n] [-xF] [-F] [-b] [-i] file.s ...

[Bug target/51793] pragma GCC optimize wrapv leads to invalid code on Solaris

[rguenth at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=51793

Richard Guenther <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Target|i386-pc-solaris2.11         |x86_64-*-*, i?86-*-*
             Status|UNCONFIRMED                 |NEW
   Last reconfirmed|                            |2012-01-09
               Host|i386-pc-solaris2.11         |
     Ever Confirmed|0                           |1
              Build|i386-pc-solaris2.11         |

--- Comment #1 from Richard Guenther <rguenth at gcc dot gnu.org> 2012-01-09 11:59:09 UTC ---
Huh, weird.  Works with GCC 4.3 (which does not implement the pragma).

Confirmed.  At least generic x86 is affected.

[Bug target/51793] pragma GCC optimize wrapv leads to invalid code on Solaris

[egallager at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=51793

Eric Gallager <egallager at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |egallager at gcc dot gnu.org

--- Comment #2 from Eric Gallager <egallager at gcc dot gnu.org> ---
I've seen this bug referenced in some versions of gnulib's mktime.c; is it
still relevant?

[Bug target/51793] pragma GCC optimize wrapv leads to invalid code on Solaris

[bruno at clisp dot org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=51793

Bruno Haible <bruno at clisp dot org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |RESOLVED
      Known to fail|                            |4.5.4, 4.6.4, 4.7.3, 4.8.5,
                   |                            |4.9.4
      Known to work|                            |10.3.0, 11.1.0, 5.5.0,
                   |                            |6.5.0, 7.5.0, 8.4.0, 9.3.0
         Resolution|---                         |FIXED

--- Comment #3 from Bruno Haible <bruno at clisp dot org> ---
It works fine on
- Solaris 11.4 (gcc 7.3.0): foo.s contains '.p2align 4,,15'
- Solaris 11 OpenIndiana (gcc 7.2.0): likewise
- Solaris 11 OmniOS (gcc 9.3.0): foo.s does not contain .p2align directives any
more

More details by testing various versions on i386-pc-linux-gnu:

4.5.4 -> .p2align 4,,-1
4.6.4 -> .p2align 4,,-1
4.7.3 -> .p2align 4,,-1
4.8.5 -> .p2align 4,,-1
4.9.4 -> .p2align 4,,-1
5.5.0 -> no .p2align any more
6.5.0 -> .p2align 4,,15
7.5.0 -> .p2align 4,,15
8.4.0 -> .p2align 4,,15
9.3.0 -> .p2align 4
10.3.0 -> .p2align 4
11.1.0 -> .p2align 4

In summary, it appears to be fixed since GCC version 5.x.

[Bug target/51793] pragma GCC optimize wrapv leads to invalid code on Solaris

[bruno at clisp dot org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=51793

--- Comment #4 from Bruno Haible <bruno at clisp dot org> ---
Correction to comment #3:
It works fine on
- Solaris 11.4 (gcc 7.3.0): foo.s contains '.p2align 4,,15'
- Solaris 11 OpenIndiana (gcc 7.2.0): likewise
- Solaris 11 OmniOS (gcc 9.3.0): foo.s contains '.p2align 4'

Consistently with what we see on Linux.