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

[dietmar.schind...@manroland-web.com]

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

--- Comment #5 from Dietmar Schindler dietmar.schind...@manroland-web.com ---
(In reply to steveren from comment #3)
 Is there any public discussion of the rationale behind this design decision?

In news:comp.std.c there is a thread #pragma are considered statements -
https://groups.google.com/forum/#!topic/comp.std.c/A1rhyQ5zB7g/discussion - not
about the design decision, but about the behaviour per se.

[Bug c/63326] pragma GCC causes wrong code generation

[dietmar.schind...@manroland-web.com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63326

--- Comment #2 from Dietmar Schindler dietmar.schind...@manroland-web.com ---
(In reply to Andrew Pinski from comment #1)
 #pragma are considered statements.

This can't be entirely true, since #pragma can be used where statements cannot
(outside of functions), and #pragma STDC certainly isn't considered a
statement.
At least, this implementation-defined behaviour has to be documented (hasn't
it?), and I couldn't find mention of it in the documentation. Would you
recommend filing a separate documentation bug report?

[Bug c/63326] New: pragma GCC causes wrong code generation

[dietmar.schind...@manroland-web.com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63326

Bug ID: 63326
   Summary: pragma GCC causes wrong code generation
   Product: gcc
   Version: 4.9.1
Status: UNCONFIRMED
  Severity: normal
  Priority: P3
 Component: c
  Assignee: unassigned at gcc dot gnu.org
  Reporter: dietmar.schind...@manroland-web.com

Created attachment 33530
  -- https://gcc.gnu.org/bugzilla/attachment.cgi?id=33530action=edit
preprocessed file

The following command generates wrong code, returning 1 instead of 0 (as if the
pragma line ended the statement in which it is placed).

raeksrv1:~/bin/so/c /tmp/usr/local/bin/gcc -v -save-temps bug.c -o bug 
Using built-in specs.
COLLECT_GCC=/tmp/usr/local/bin/gcc
COLLECT_LTO_WRAPPER=/tmp/usr/local/bin/../libexec/gcc/x86_64-unknown-linux-gnu/4.9.1/lto-wrapper
Target: x86_64-unknown-linux-gnu
Configured with: ../gcc-4.9.1/configure --enable-plugin --disable-libsanitizer
: (reconfigured) ../gcc-4.9.1/configure --enable-plugin --enable-languages=c
--disable-libsanitizer : (reconfigured) ../gcc-4.9.1/configure --enable-plugin
--enable-languages=c --disable-libsanitizer --disable-libcilkrts
Thread model: posix
gcc version 4.9.1 (GCC) 
COLLECT_GCC_OPTIONS='-v' '-save-temps' '-o' 'bug' '-mtune=generic'
'-march=x86-64'
 /tmp/usr/local/bin/../libexec/gcc/x86_64-unknown-linux-gnu/4.9.1/cc1 -E -quiet
-v -iprefix /tmp/usr/local/bin/../lib/gcc/x86_64-unknown-linux-gnu/4.9.1/ bug.c
-mtune=generic -march=x86-64 -fpch-preprocess -o bug.i
ignoring nonexistent directory
/tmp/usr/local/bin/../lib/gcc/x86_64-unknown-linux-gnu/4.9.1/../../../../x86_64-unknown-linux-gnu/include
ignoring duplicate directory
/tmp/usr/local/bin/../lib/gcc/../../lib/gcc/x86_64-unknown-linux-gnu/4.9.1/include
ignoring duplicate directory
/tmp/usr/local/bin/../lib/gcc/../../lib/gcc/x86_64-unknown-linux-gnu/4.9.1/include-fixed
ignoring nonexistent directory
/tmp/usr/local/bin/../lib/gcc/../../lib/gcc/x86_64-unknown-linux-gnu/4.9.1/../../../../x86_64-unknown-linux-gnu/include
#include ... search starts here:
#include ... search starts here:
 /tmp/usr/local/bin/../lib/gcc/x86_64-unknown-linux-gnu/4.9.1/include
 /tmp/usr/local/bin/../lib/gcc/x86_64-unknown-linux-gnu/4.9.1/include-fixed
 /usr/local/include
 /usr/include
End of search list.
COLLECT_GCC_OPTIONS='-v' '-save-temps' '-o' 'bug' '-mtune=generic'
'-march=x86-64'
 /tmp/usr/local/bin/../libexec/gcc/x86_64-unknown-linux-gnu/4.9.1/cc1
-fpreprocessed bug.i -quiet -dumpbase bug.c -mtune=generic -march=x86-64
-auxbase bug -version -o bug.s
GNU C (GCC) version 4.9.1 (x86_64-unknown-linux-gnu)
compiled by GNU C version 4.9.1, GMP version 4.3.2, MPFR version 2.4.2,
MPC version 0.8.1
GGC heuristics: --param ggc-min-expand=100 --param ggc-min-heapsize=131072
GNU C (GCC) version 4.9.1 (x86_64-unknown-linux-gnu)
compiled by GNU C version 4.9.1, GMP version 4.3.2, MPFR version 2.4.2,
MPC version 0.8.1
GGC heuristics: --param ggc-min-expand=100 --param ggc-min-heapsize=131072
Compiler executable checksum: aa505e323dbffe0cb500ba62f983d917
COLLECT_GCC_OPTIONS='-v' '-save-temps' '-o' 'bug' '-mtune=generic'
'-march=x86-64'
 as -v --64 -o bug.o bug.s
GNU assembler version 2.20.1 (i486-linux-gnu) using BFD version (GNU Binutils
for Debian) 2.20.1-system.20100303
COMPILER_PATH=/tmp/usr/local/bin/../libexec/gcc/x86_64-unknown-linux-gnu/4.9.1/:/tmp/usr/local/bin/../libexec/gcc/
LIBRARY_PATH=/tmp/usr/local/bin/../lib/gcc/x86_64-unknown-linux-gnu/4.9.1/:/tmp/usr/local/bin/../lib/gcc/:/tmp/usr/local/bin/../lib/gcc/x86_64-unknown-linux-gnu/4.9.1/../../../../lib64/:/lib/../lib64/:/usr/lib/../lib64/:/tmp/usr/local/bin/../lib/gcc/x86_64-unknown-linux-gnu/4.9.1/../../../:/lib/:/usr/lib/
COLLECT_GCC_OPTIONS='-v' '-save-temps' '-o' 'bug' '-mtune=generic'
'-march=x86-64'
 /tmp/usr/local/bin/../libexec/gcc/x86_64-unknown-linux-gnu/4.9.1/collect2
--eh-frame-hdr -m elf_x86_64 -dynamic-linker /lib64/ld-linux-x86-64.so.2 -o bug
/usr/lib/../lib64/crt1.o /usr/lib/../lib64/crti.o
/tmp/usr/local/bin/../lib/gcc/x86_64-unknown-linux-gnu/4.9.1/crtbegin.o
-L/tmp/usr/local/bin/../lib/gcc/x86_64-unknown-linux-gnu/4.9.1
-L/tmp/usr/local/bin/../lib/gcc
-L/tmp/usr/local/bin/../lib/gcc/x86_64-unknown-linux-gnu/4.9.1/../../../../lib64
-L/lib/../lib64 -L/usr/lib/../lib64
-L/tmp/usr/local/bin/../lib/gcc/x86_64-unknown-linux-gnu/4.9.1/../../.. bug.o
-lgcc --as-needed -lgcc_s --no-as-needed -lc -lgcc --as-needed -lgcc_s
--no-as-needed
/tmp/usr/local/bin/../lib/gcc/x86_64-unknown-linux-gnu/4.9.1/crtend.o
/usr/lib/../lib64/crtn.o