Need a bit of help in tracking down a problem with gcc -fprofile-arcs -ftest-coverage

[Bradley Lucier <lucier@xxxxxxxxxxxxxxx>]

I'm finding that the following command

    /pkgs/gcc-4.9.2/bin/gcc -Q -save-temps -Wno-unused 
-Wno-write-strings -O1 -fno-math-errno -fschedule-insns2 
-fno-strict-aliasing -fno-trapping-math -fwrapv -fomit-frame-pointer 
-fPIC -fno-common -mieee-fp  -fprofile-arcs -ftest-coverage 
-I"../include" -c -o "_io.o" -I. -DHAVE_CONFIG_H 
-D___GAMBCDIR="\"/usr/local/Gambit-C\"" -D___SYS_TYPE_CPU="\"x86_64\"" 
-D___SYS_TYPE_VENDOR="\"unknown\"" -D___SYS_TYPE_OS="\"linux-gnu\"" 
-D___CONFIGURE_COMMAND="\"./configure 'CC=/pkgs/gcc-4.9.2/bin/gcc -Q 
-save-temps' '--enable-track-scheme' '--enable-coverage'"\" 
-D___OBJ_EXTENSION="\".o\"" -D___EXE_EXTENSION="\"\"" 
-D___BAT_EXTENSION="\"\"" -D___PRIMAL _io.c -D___LIBRARY


With gcc configured as

    firefly:~/Downloads/gambit> /pkgs/gcc-4.9.2/bin/gcc -v
    Using built-in specs.
    COLLECT_GCC=/pkgs/gcc-4.9.2/bin/gcc

COLLECT_LTO_WRAPPER=/pkgs/gcc-4.9.2/libexec/gcc/x86_64-unknown-linux-gnu/4.9.2/lto-wrapper
    Target: x86_64-unknown-linux-gnu
    Configured with: ../../gcc-4.9.2/configure --prefix=/pkgs/gcc-4.9.2
    Thread model: posix
    gcc version 4.9.2 (GCC)


takes effectively infinite amount of memory (>80GB) on some (rather 
large) functions in (rather large) C files.

So I put in the -Q to try to track what gcc was doing; I killed it at

    Analyzing compilation unit
    Performing interprocedural optimizations
     <*free_lang_data> <visibility> <early_local_cleanups> 
<*free_inline_summary> <profile> <whole-program> <profile_estimate> 
<inline> <pure-const> <static-var>Assembling functions:
     ___setup_mod ___init_mod 
___H__23__23_make_2d_standard_2d_readtable ___H__23__23_six_2d_type_3f_ 
___H__23__23_read_2d_six_2d_datum_2d_or_2d_eof {GC 737902k -> 689272k}^C


So, some questions:

1.  Is it really performing interprocedural optimizations at -O1?

2.  Was it really processing 
___H__23__23_read_2d_six_2d_datum_2d_or_2d_eof when I killed it?

3.  How can I get some more detailed information about what gcc is doing?

This is C code automatically generated from a Scheme file.  Without the 
-ftest-coverage -fprofile-arcs gcc has no problem dealing with it, even 
if I compile the entire .scm file to a single C function.

Thanks.

Brad