[Bug c++/56926] Crash (without ICE) while compiling Boost.Math

["asmwarrior at gmail dot com" <gcc-bugzilla at gcc dot gnu dot org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=56926

--- Comment #14 from asmwarrior <asmwarrior at gmail dot com> ---
The bug can be seen when "-E" and "-fpch-preprocess" is used together to
generate a preprocessed file.
If I have a small pch file named "spch.h" and "spch.h.gch"(note the spch.h.gch
size is about 47M), and if I have a test.cpp like below:
------
#include "spch.h"

int main()
{
        int a;
        int b;
        int c;
        a++;
        b++;
}
------

Then, run the command:
g++.exe -v -E -Wall -fexceptions  -g -march=core2 -Wall
-ID:\mingw-builds\boost_1_55_0  -Winvalid-pch -include spch.h test.cpp
-fpch-preprocess -o xxx.ii -ftime-report

I will get a xxx.ii containing such contents:
------
# 1 "test.cpp"
# 1 "D:\\mingw-builds\\test-51//"
# 1 "<built-in>"
# 1 "<command-line>"
#pragma GCC pch_preprocess "./spch.h.gch"
# 1 "test.cpp"
# 1 "spch.h" 1
# 2 "test.cpp" 2

int main()
{
 int a;
 int b;
 int c;
 a++;
 b++;
}
------

You see, the line "#pragma GCC pch_preprocess "./spch.h.gch"" is generated
correctly, which means G++ load the pch file correctly. (That's what the
-fpch-preprocess option used for, see:
https://gcc.gnu.org/onlinedocs/gcc/Preprocessor-Options.html)

But if I use a big pch file "pch.h.gch", and run the similar command line like
above, I don't see any .ii file generated, which means G++ crashed before log
out the line "#pragma GCC pch_preprocess ...".

By reading the source code, I see that in gcc-4.9.2\gcc\c-family\c-ppoutput.c,
there is a function:

/* Load in the PCH file NAME, open on FD.  It was originally searched for
   by ORIG_NAME.  Also, print out a #include command so that the PCH
   file can be loaded when the preprocessed output is compiled.  */

static void
cb_read_pch (cpp_reader *pfile, const char *name,
             int fd, const char *orig_name ATTRIBUTE_UNUSED)
{
  c_common_read_pch (pfile, name, fd, orig_name);

  fprintf (print.outf, "#pragma GCC pch_preprocess \"%s\"\n", name);
  print.src_line++;
}

So, the bug happens before the fprintf() function, maybe inside the
c_common_read_pch function call. 

I would like to see anyone can supply a debug version of 32bit cc1plus.exe, so
that I can hunt the bug further under GDB, because building the whole gcc tool
chain is too difficult for me.