[Bug tree-optimization/49018] New: Inline assembly block executed outside conditional check with "-O1 -ftree-vrp"

["ted at thereisnospork dot com" <gcc-bugzilla at gcc dot gnu dot org>]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49018

           Summary: Inline assembly block executed outside conditional
                    check with "-O1 -ftree-vrp"
           Product: gcc
           Version: 4.6.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: tree-optimization
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: ted@thereisnospork.com


In the following test case, the int3 instruction inserted by the assertion
macro is executed before any conditional check is performed when compiled with
"-O1 -ftree-vrp".  Without -ftree-vrp (as well as "-O2 -fno-tree-vrp"), the
instructions are ordered as expected.

$ cat asmvolatiletest.c 
#include <stdio.h>

#define CUSTOM_ASSERT( X ) if( !( X ) ) { __asm__ __volatile__ ( "int3" ); }

void testFunction( unsigned int a, unsigned int b )
{
    CUSTOM_ASSERT( a >= b );
    if( a < b )
    {
        printf( "Error: %u < %u\n", a, b );
    }
}

$ gcc -v
Using built-in specs.
COLLECT_GCC=/usr/bin/gcc
COLLECT_LTO_WRAPPER=/usr/lib64/gcc/x86_64-mandriva-linux-gnu/4.6.0/lto-wrapper
Target: x86_64-mandriva-linux-gnu
Configured with: ./configure --build=x86_64-mandriva-linux-gnu --prefix=/usr
--exec-prefix=/usr --bindir=/usr/bin --sbindir=/usr/sbin --sysconfdir=/etc
--datadir=/usr/share --includedir=/usr/include --libdir=/usr/lib64
--libexecdir=/usr/lib64 --localstatedir=/var --sharedstatedir=/usr/com
--mandir=/usr/share/man --infodir=/usr/share/info --x-includes=/usr/include
--x-libraries=/usr/lib64 --disable-libgcj --with-cloog --with-ppl
--enable-cloog-backend=ppl --disable-libssp --disable-libunwind-exceptions
--disable-werror --enable-__cxa_atexit --enable-bootstrap
--enable-checking=release --enable-gnu-unique-object
--enable-languages=c,ada,c++,fortran,go,lto,objc,obj-c++
--enable-linker-build-id --enable-plugin --enable-shared --enable-threads=posix
--with-system-zlib --with-bugurl=https://qa.mandriva.com/ --with-tune=generic
--with-arch_32=i686 --host=x86_64-mandriva-linux-gnu
--target=x86_64-mandriva-linux-gnu
Thread model: posix
gcc version 4.6.0 20110513 (prerelease) (GCC)