http://gcc.gnu.org/bugzilla/show_bug.cgi?id=60317
Bug ID: 60317
Summary: [4.9 Regression] find_hard_regno_for compile time hog
in libvpx
Product: gcc
Version: 4.9.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: rtl-optimization
Assignee: unassigned at gcc dot gnu.org
Reporter: trippels at gcc dot gnu.org
CC: vmakarov at gcc dot gnu.org
While building Firefox I've noticed that there is a file from libvpx
that takes almost 2 minutes to compile on my machine:
% time gcc -O3 -c sad_c.i
gcc -O3 -c sad_c.i 111.05s user 0.78s system 99% cpu 1:52.10 total
phase opt and generate : 110.92 (100%) usr 0.43 (100%) sys 111.43 (100%)
wall 168173 kB (99%) ggc
Perf shows:
87.86% cc1 cc1 [.] find_hard_regno_for(int, int*, int)
- find_hard_regno_for(int, int*, int)
99.77% 0x10101010101
0.72% cc1 cc1 [.] find_base_term(rtx_def*)
It's fine with -O2 or 4.8.3:
% time gcc -O2 -c sad_c.i
gcc -O2 -c sad_c.i 0.25s user 0.02s system 99% cpu 0.273 total
phase opt and generate : 0.23 (96%) usr 0.02 (100%) sys 0.25 (93%) wall
8876 kB (84%) ggc
% time /usr/x86_64-pc-linux-gnu/gcc-bin/4.8.3/gcc -w -O3 -c sad_c.i
/usr/x86_64-pc-linux-gnu/gcc-bin/4.8.3/gcc -w -O3 -c sad_c.i 0.94s user 0.02s
system 99% cpu 0.964 total
