[Bug c/63612] New: #pragma breaks if...else

[q.gcc@rsn-tech.co.uk]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63612

            Bug ID: 63612
           Summary: #pragma breaks if...else
           Product: gcc
           Version: 4.8.3
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c
          Assignee: unassigned at gcc dot gnu.org
          Reporter: q.gcc@rsn-tech.co.uk

The following program fails to compile, giving the error "else without a
previous if". Removing (or commenting out) the #pragma restores correct
behaviour.

    int main (int argc, char *argv[])
    {
    if (argc == 1)
        return 1;
    #pragma message ("This is a message")
    else
        return 0;
    }

Other valid pragmas (such as #pragma pack) also exhibit this bug, but invalid
ones (like #pragma asasdadf) don't, nor do other preprocessor directives (such
as #define FOO).

It exists in at least two builds of gcc 4.8.3, in ARM cross-compilation and
native x64:

$ /opt/Xilinx/SDK/current/gnu/arm/lin/arm-xilinx-eabi/bin/gcc -v
Using built-in specs.
COLLECT_GCC=/opt/Xilinx/SDK/current/gnu/arm/lin/arm-xilinx-eabi/bin/gcc
Target: arm-xilinx-eabi
Configured with:
/scratch/janisjo/build7/2014.05-xilinx-eabi-preview/src/gcc-4.8-2014.05/configure
--build=i686-pc-linux-gnu --host=i686-pc-linux-gnu --target=arm-xilinx-eabi
--enable-threads --disable-libmudflap --disable-libssp --disable-libstdcxx-pch
--with-arch=armv7-a --with-cpu=cortex-a9 --with-float=softfp
--with-fpu=neon-fp16 --disable-multilib --with-gnu-as --with-gnu-ld
--with-specs='%{save-temps: -fverbose-asm} -D__CS_SOURCERYGXX_MAJ__=2014
-D__CS_SOURCERYGXX_MIN__=5 -D__CS_SOURCERYGXX_REV__=22'
--enable-languages=c,c++ --disable-shared --enable-lto --with-newlib
--with-pkgversion='Sourcery CodeBench Lite 2014.05-22'
--with-bugurl=https://sourcery.mentor.com/GNUToolchain/ --disable-nls
--prefix=/opt/codesourcery --with-headers=yes
--with-sysroot=/opt/codesourcery/arm-xilinx-eabi
--with-build-sysroot=/scratch/janisjo/build7/2014.05-xilinx-eabi-preview/install/opt/codesourcery/arm-xilinx-eabi
--with-gmp=/scratch/janisjo/build7/2014.05-xilinx-eabi-preview/obj/pkg-2014.05-22-arm-xilinx-eabi/xilinx-2014.05-22-arm-xilinx-eabi.extras/host-libs-i686-pc-linux-gnu/usr
--with-mpfr=/scratch/janisjo/build7/2014.05-xilinx-eabi-preview/obj/pkg-2014.05-22-arm-xilinx-eabi/xilinx-2014.05-22-arm-xilinx-eabi.extras/host-libs-i686-pc-linux-gnu/usr
--with-mpc=/scratch/janisjo/build7/2014.05-xilinx-eabi-preview/obj/pkg-2014.05-22-arm-xilinx-eabi/xilinx-2014.05-22-arm-xilinx-eabi.extras/host-libs-i686-pc-linux-gnu/usr
--with-isl=/scratch/janisjo/build7/2014.05-xilinx-eabi-preview/obj/pkg-2014.05-22-arm-xilinx-eabi/xilinx-2014.05-22-arm-xilinx-eabi.extras/host-libs-i686-pc-linux-gnu/usr
--with-cloog=/scratch/janisjo/build7/2014.05-xilinx-eabi-preview/obj/pkg-2014.05-22-arm-xilinx-eabi/xilinx-2014.05-22-arm-xilinx-eabi.extras/host-libs-i686-pc-linux-gnu/usr
--disable-libgomp --disable-libitm --disable-libatomic --disable-libssp
--enable-poison-system-directories
--with-build-time-tools=/scratch/janisjo/build7/2014.05-xilinx-eabi-preview/install/opt/codesourcery/arm-xilinx-eabi/bin
--with-build-time-tools=/scratch/janisjo/build7/2014.05-xilinx-eabi-preview/install/opt/codesourcery/arm-xilinx-eabi/bin
SED=sed
Thread model: single
gcc version 4.8.3 20140320 (prerelease) (Sourcery CodeBench Lite 2014.05-22) 

$ gcc -v
Using built-in specs.
COLLECT_GCC=/usr/bin/gcc
COLLECT_LTO_WRAPPER=/usr/libexec/gcc/x86_64-redhat-linux/4.8.3/lto-wrapper
Target: x86_64-redhat-linux
Configured with: ../configure --prefix=/usr --mandir=/usr/share/man
--infodir=/usr/share/info --with-bugurl=http://bugzilla.redhat.com/bugzilla
--enable-bootstrap --enable-shared --enable-threads=posix
--enable-checking=release --with-system-zlib --enable-__cxa_atexit
--disable-libunwind-exceptions --enable-gnu-unique-object
--enable-linker-build-id --with-linker-hash-style=gnu
--enable-languages=c,c++,objc,obj-c++,java,fortran,ada,go,lto --enable-plugin
--enable-initfini-array --enable-java-awt=gtk --disable-dssi
--with-java-home=/usr/lib/jvm/java-1.5.0-gcj-1.5.0.0/jre
--enable-libgcj-multifile --enable-java-maintainer-mode
--with-ecj-jar=/usr/share/java/eclipse-ecj.jar --disable-libjava-multilib
--with-isl=/builddir/build/BUILD/gcc-4.8.3-20140911/obj-x86_64-redhat-linux/isl-install
--with-cloog=/builddir/build/BUILD/gcc-4.8.3-20140911/obj-x86_64-redhat-linux/cloog-install
--with-tune=generic --with-arch_32=i686 --build=x86_64-redhat-linux
Thread model: posix
gcc version 4.8.3 20140911 (Red Hat 4.8.3-7) (GCC)