[Bug tree-optimization/26854] Inordinate compile times on large routines

[lucier at math dot purdue.edu]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=26854

--- Comment #132 from lucier at math dot purdue.edu ---
Created attachment 37763
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=37763&action=edit
Detailed time/memory report when compiling _num.i

Generated with

heine:~/Downloads> /pkgs/gcc-mainline/bin/gcc -v
Using built-in specs.
COLLECT_GCC=/pkgs/gcc-mainline/bin/gcc
COLLECT_LTO_WRAPPER=/pkgs/gcc-mainline/libexec/gcc/x86_64-pc-linux-gnu/6.0.0/lto-wrapper
Target: x86_64-pc-linux-gnu
Configured with: ../../gcc-mainline/configure --prefix=/pkgs/gcc-mainline
--enable-checking=release --enable-languages=c --disable-multilib
--enable-gather-detailed-mem-stats
Thread model: posix
gcc version 6.0.0 20160222 (experimental) (GCC) 
heine:~/Downloads> /pkgs/gcc-mainline/bin/gcc -v -c -O2 -fmem-report
-ftime-report _num.i -save-temps > & ! report-compiler_num2

There are some negative numbers in the file that suggest that some bitmap
memory counters overflowed:

tree-ssa-structalias.c:1268 (build_pred_graph)     62026224: 15.9%  62048368  
7961338:  8.5%      186859      248364      heap
df-problems.c:3658 (df_note_compute)               88025520: 22.6%  88026080  
3719686:  4.0%      515641     1741186      heap
df-problems.c:4405 (df_md_alloc)                  -39759960:4741239668736.0%   
   -40    520627:  0.6%           0           0      heap
df-problems.c:225 (df_rd_alloc)                   -17948440:4741239668736.0%   
   -40    284572:  0.3%           0           0      heap
--------------------------------------------------------------------------------------------------------------------------------------------
Total                                             389070056                  
94152365