[Bug tree-optimization/26144] New: with -O3 and pointer casts, gcc skips if

[gcc-bugzilla at gcc dot gnu dot org]

        When casting a pointer and checking for == NULL, the check is skipped
        when -O3 is enabled.  I found this problem while compiling bind with
uClibc,
        but could reproduce the problem with the debian version of gcc and this
simple
        test file.

Environment:
System: Linux dungeon2 2.6.11-1-k7-smp #1 SMP Mon Jun 20 22:34:51 MDT 2005 i686
GNU/Linux
Architecture: i686


host: i486-pc-linux-gnu
build: i486-pc-linux-gnu
target: i486-pc-linux-gnu
configured with: ../src/configure -v
--enable-languages=c,c++,java,f95,objc,ada,treelang --prefix=/usr
--enable-shared --with-system-zlib --libexecdir=/usr/lib
--without-included-gettext --enable-threads=posix --enable-nls
--program-suffix=-4.0 --enable-__cxa_atexit --enable-clocale=gnu
--enable-libstdcxx-debug --enable-java-awt=gtk-default --enable-gtk-cairo
--with-java-home=/usr/lib/jvm/java-1.4.2-gcj-4.0-1.4.2.0/jre --enable-mpfr
--disable-werror --with-tune=i686 --enable-checking=release i486-linux-gnu

How-To-Repeat:
        Compile this file:

        #include <stdio.h>
        void foo(char **dee) {  *dee = ""; }
        int main(int argc, char *argv[])
            {
            struct blah *ptr = argv[1];
            if(ptr == NULL)
                foo(&ptr);
            printf("%p", ptr); // output: (nil) expected: 0xADDRESS
            return 0;
            }


-- 
           Summary: with -O3 and pointer casts, gcc skips if
           Product: gcc
           Version: 4.0.3
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: tree-optimization
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: devin at dungeon2 dot cainetworks dot com
 GCC build triplet: i486-pc-linux-gnu
  GCC host triplet: i486-pc-linux-gnu
GCC target triplet: i486-pc-linux-gnu


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=26144