[Bug c++/50970] New: Function pointer dereferenced twice in if statement on Arm cpu

[emillbrandt at dekaresearch dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50970

             Bug #: 50970
           Summary: Function pointer dereferenced twice in if statement on
                    Arm cpu
    Classification: Unclassified
           Product: gcc
           Version: unknown
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: emillbrandt@dekaresearch.com


Created attachment 25695
  --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=25695
Test case that produces the error

We have a test case which shows that a function pointer can be dereferenced
twice when it is in an if statement that evaluates to true.  This error only
occurs when building for arm; powerpc and x86 work as expected.  The test case
is attached.

I have been able to reproduce the error with g++ 4.3.4 (CodeSourcery/Win32),
4.4.3 (Ubuntu/arm), and 4.5.2 (CodeSourcery/Win32).

root@pluto-armeem2:~# g++ -o gcc_test2 -v --save-temps test.cpp
Using built-in specs.
Target: arm-linux-gnueabi
Configured with: ../src/configure -v --with-pkgversion='Ubuntu 4.4.3-4ubuntu5'
--with-bugurl=file:///usr/share/doc/gcc-4.4/README.Bugs
--enable-languages=c,c++,fortran,objc,obj-c++ --prefix=/usr --enable-shared
--enable-multiarch --enable-linker-build-id --with-system-zlib
--libexecdir=/usr/lib --without-included-gettext --enable-threads=posix
--with-gxx-include-dir=/usr/include/c++/4.4 --program-suffix=-4.4 --enable-nls
--enable-clocale=gnu --enable-libstdcxx-debug --enable-plugin --enable-objc-gc
--disable-sjlj-exceptions --with-arch=armv7-a --with-float=softfp
--with-fpu=vfpv3-d16 --with-mode=thumb --disable-werror
--enable-checking=release --build=arm-linux-gnueabi --host=arm-linux-gnueabi
--target=arm-linux-gnueabi
Thread model: posix
gcc version 4.4.3 (Ubuntu 4.4.3-4ubuntu5)
COLLECT_GCC_OPTIONS='-o' 'gcc_test2' '-v' '-save-temps' '-shared-libgcc'
'-march=armv7-a' '-mfloat-abi=softfp' '-mfpu=vfpv3-d16' '-mthumb'
 /usr/lib/gcc/arm-linux-gnueabi/4.4.3/cc1plus -E -quiet -v -D_GNU_SOURCE
test.cpp -D_FORTIFY_SOURCE=2 -march=armv7-a -mfloat-abi=softfp -mfpu=vfpv3-d16
-mthumb -fpch-preprocess -fstack-protector -o test.ii
\ignoring nonexistent directory "/usr/local/include/arm-linux-gnueabi"
ignoring nonexistent directory
"/usr/lib/gcc/arm-linux-gnueabi/4.4.3/../../../../arm-linux-gnueabi/include"
ignoring nonexistent directory "/usr/include/arm-linux-gnueabi"
#include "..." search starts here:
#include <...> search starts here:
 /usr/include/c++/4.4
 /usr/include/c++/4.4/arm-linux-gnueabi
 /usr/include/c++/4.4/backward
 /usr/local/include
 /usr/lib/gcc/arm-linux-gnueabi/4.4.3/include
 /usr/lib/gcc/arm-linux-gnueabi/4.4.3/include-fixed
 /usr/include
End of search list.
COLLECT_GCC_OPTIONS='-o' 'gcc_test2' '-v' '-save-temps' '-shared-libgcc'
'-march=armv7-a' '-mfloat-abi=softfp' '-mfpu=vfpv3-d16' '-mthumb'
 /usr/lib/gcc/arm-linux-gnueabi/4.4.3/cc1plus -fpreprocessed test.ii -quiet
-dumpbase test.cpp -march=armv7-a -mfloat-abi=softfp -mfpu=vfpv3-d16 -mthumb
-auxbase test -version -fstack-protector -o test.s
GNU C++ (Ubuntu 4.4.3-4ubuntu5) version 4.4.3 (arm-linux-gnueabi)
        compiled by GNU C version 4.4.3, GMP version 4.3.2, MPFR version
2.4.2-p1.
GGC heuristics: --param ggc-min-expand=81 --param ggc-min-heapsize=96734
GNU C++ (Ubuntu 4.4.3-4ubuntu5) version 4.4.3 (arm-linux-gnueabi)
        compiled by GNU C version 4.4.3, GMP version 4.3.2, MPFR version
2.4.2-p1.
GGC heuristics: --param ggc-min-expand=81 --param ggc-min-heapsize=96734
Compiler executable checksum: 21e593b38856b3f9b424e99bf2ade079
COLLECT_GCC_OPTIONS='-o' 'gcc_test2' '-v' '-save-temps' '-shared-libgcc'
'-march=armv7-a' '-mfloat-abi=softfp' '-mfpu=vfpv3-d16' '-mthumb'
 as -march=armv7-a -mfloat-abi=softfp -mfpu=vfpv3-d16 -meabi=5
-mimplicit-it=thumb -o test.o test.s
COMPILER_PATH=/usr/lib/gcc/arm-linux-gnueabi/4.4.3/:/usr/lib/gcc/arm-linux-gnueabi/4.4.3/:/usr/lib/gcc/arm-linux-gnueabi/:/usr/lib/gcc/arm-linux-gnueabi/4.4.3/:/usr/lib/gcc/arm-linux-gnueabi/:/usr/lib/gcc/arm-linux-gnueabi/4.4.3/:/usr/lib/gcc/arm-linux-gnueabi/
LIBRARY_PATH=/usr/lib/gcc/arm-linux-gnueabi/4.4.3/:/usr/lib/gcc/arm-linux-gnueabi/4.4.3/:/usr/lib/gcc/arm-linux-gnueabi/4.4.3/../../../:/lib/:/usr/lib/
COLLECT_GCC_OPTIONS='-o' 'gcc_test2' '-v' '-save-temps' '-shared-libgcc'
'-march=armv7-a' '-mfloat-abi=softfp' '-mfpu=vfpv3-d16' '-mthumb'
 /usr/lib/gcc/arm-linux-gnueabi/4.4.3/collect2 --build-id --eh-frame-hdr
-dynamic-linker /lib/ld-linux.so.3 -X --hash-style=both -m armelf_linux_eabi -o
gcc_test2 -z relro /usr/lib/gcc/arm-linux-gnueabi/4.4.3/../../../crt1.o
/usr/lib/gcc/arm-linux-gnueabi/4.4.3/../../../crti.o
/usr/lib/gcc/arm-linux-gnueabi/4.4.3/crtbegin.o
-L/usr/lib/gcc/arm-linux-gnueabi/4.4.3 -L/usr/lib/gcc/arm-linux-gnueabi/4.4.3
-L/usr/lib/gcc/arm-linux-gnueabi/4.4.3/../../.. test.o -lstdc++ -lm -lgcc_s
-lgcc -lc -lgcc_s -lgcc /usr/lib/gcc/arm-linux-gnueabi/4.4.3/crtend.o
/usr/lib/gcc/arm-linux-gnueabi/4.4.3/../../../crtn.o