[Bug tree-optimization/56075] New: [gcc-4.7.1] 64-bit version, -Os eliminate some line of code which working fine in gcc-4.6.2 64-bit version

[Bug tree-optimization/56075] New: [gcc-4.7.1] 64-bit version, -Os eliminate some line of code which working fine in gcc-4.6.2 64-bit version

[rajendiran.public at gmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=56075

             Bug #: 56075
           Summary: [gcc-4.7.1] 64-bit version, -Os eliminate some line of
                    code which working fine in gcc-4.6.2 64-bit version
    Classification: Unclassified
           Product: gcc
           Version: 4.7.1
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: tree-optimization
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: rajendiran.public@gmail.com


Created attachment 29247
  --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=29247
C source code

With attached sample C codes, assembly code for C code at LINE-1 is not at all
generated in gcc-4.7.1(64-bit) but gcc-4.6.2(64-bit) generate it correctly.

void fun( struct semaphore *s1,struct semaphore *s2)
{
  ...
 { struct semaphore __mutex = { .lock = (spinlock_t ) { { .rlock = { .raw_lock
= { 0 }, .magic = 0xdead4ead, .owner_cpu = -1, .owner = ((void *)-1L), .dep_map
= { .name = "(*(s1)).lock" } } } }, .count = 1, .wait_list = {
&((*(s1)).wait_list), &((*(s1)).wait_list) }, }; *(s1) = __mutex; }; // LINE-1

 { struct semaphore __mutex = { .lock = (spinlock_t ) { { .rlock = { .raw_lock
= { 0 }, .magic = 0xdead4ead, .owner_cpu = -1, .owner = ((void *)-1L), .dep_map
= { .name = "(*(s2)).lock" } } } }, .count = 1, .wait_list = {
&((*(s2)).wait_list), &((*(s2)).wait_list) }, }; *(s2) = __mutex; };  //LINE-2
 ...
}

Source Code Compiling options in GCC-4.7.1
------------------------------------------

gcc -nostdinc -isystem /usr/lib64/gcc/x86_64-unknown-linux-gnu/4.7.1/include
-I/linux-3.1.7-0/kernel/bld/include/
-I/linux-3.1.7-0/kernel/bld/arch/x86/include -Iarch/x86/include/generated
-Iinclude  -include /linux-3.1.7-0/kernel/bld/include/linux/kconfig.h
-D__KERNEL__ -Os -m64 -fno-strict-aliasing -mno-red-zone
-fno-omit-frame-pointer -fconserve-stack -S nv1.c

Source Code Compiling options in GCC-4.6.2
------------------------------------------

gcc -nostdinc -isystem /usr/lib64/gcc/x86_64-suse-linux/4.6/include
-I/linux-3.1.7-0/kernel/bld/include/
-I/linux-3.1.7-0/kernel/bld/arch/x86/include -Iarch/x86/include/generated
-Iinclude  -include /linux-3.1.7-0/kernel/bld/include/linux/kconfig.h
-D__KERNEL__ -Os -m64 -fno-strict-aliasing -mno-red-zone
-fno-omit-frame-pointer -fconserve-stack -S nv1.c


GCC-4.7.1 - Build Config
------------------------

Using built-in specs.
COLLECT_GCC=gcc
COLLECT_LTO_WRAPPER=/usr/bin/../lib/gcc/x86_64-unknown-linux-gnu/4.7.1/lto-wrapper
Target: x86_64-unknown-linux-gnu
Configured with: ../gcc-4.7.1/configure --prefix=/tmp/outdir/usr
Thread model: posix
gcc version 4.7.1 (GCC) 



GCC-4.6.2 Build Config
----------------------
Using built-in specs.
COLLECT_GCC=gcc
COLLECT_LTO_WRAPPER=/usr/lib64/gcc/x86_64-suse-linux/4.6/lto-wrapper
Target: x86_64-suse-linux
Configured with: ../configure --prefix=/usr --infodir=/usr/share/info
--mandir=/usr/share/man --libdir=/usr/lib64 --libexecdir=/usr/lib64
--enable-languages=c,c++,objc,fortran,obj-c++,java,ada
--enable-checking=release --with-gxx-include-dir=/usr/include/c++/4.6
--enable-ssp --disable-libssp --disable-plugin
--with-bugurl=http://bugs.opensuse.org/ --with-pkgversion='SUSE Linux'
--disable-libgcj --disable-libmudflap --with-slibdir=/lib64 --with-system-zlib
--enable-__cxa_atexit --enable-libstdcxx-allocator=new --disable-libstdcxx-pch
--enable-version-specific-runtime-libs --program-suffix=-4.6
--enable-linux-futex --without-system-libunwind --with-arch-32=i586
--with-tune=generic --build=x86_64-suse-linux
Thread model: posix
gcc version 4.6.2 (SUSE Linux)

[Bug tree-optimization/56075] [gcc-4.7.1] 64-bit version, -Os eliminate some line of code which working fine in gcc-4.6.2 64-bit version

[rajendiran.public at gmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=56075

--- Comment #1 from rajendiran <rajendiran.public at gmail dot com> 2013-01-23 10:31:45 UTC ---
Created attachment 29254
  --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=29254
C Source code without preprocced

[Bug tree-optimization/56075] [gcc-4.7.1] 64-bit version, -Os eliminate some line of code which working fine in gcc-4.6.2 64-bit version

[jakub at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=56075

Jakub Jelinek <jakub at gcc dot gnu.org> changed:

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

--- Comment #2 from Jakub Jelinek <jakub at gcc dot gnu.org> 2013-01-23 11:26:50 UTC ---
Non-preprocessed testcase is useless (the original isn't preprocessed either). 
But furthermore, why do you expect that foo won't be optimized just into an
empty function?  If fun is inlined, it doesn't have any side-effects.

[Bug tree-optimization/56075] [gcc-4.7.1] 64-bit version, -Os eliminate some line of code which working fine in gcc-4.6.2 64-bit version

[rguenth at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=56075

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |WAITING
   Last reconfirmed|                            |2013-01-23
     Ever Confirmed|0                           |1