https://gcc.gnu.org/bugzilla/show_bug.cgi?id=84552
Bug ID: 84552
Summary: [8 Regression] Compile time hog w/ -O2
-floop-nest-optimize -fno-tree-copy-prop -fno-tree-fre
-fno-tree-loop-ivcanon
Product: gcc
Version: 8.0
Status: UNCONFIRMED
Keywords: compile-time-hog
Severity: normal
Priority: P3
Component: tree-optimization
Assignee: unassigned at gcc dot gnu.org
Reporter: asolokha at gmx dot com
Target Milestone: ---
gcc-8.0.0-alpha20180218 snapshot (r257797) takes indefinite time to compile the
following snippet w/ -O2 -floop-nest-optimize -fno-tree-copy-prop -fno-tree-fre
-fno-tree-loop-ivcanon:
int cx;
int
e6 (int pj, int xe)
{
for (cx = 0; cx < 2; ++cx)
while (xe < 1)
{
for (cx = 0; cx < 2; ++cx)
pj *= 2;
if (cx != 0)
goto o3;
++xe;
}
o3:
return pj;
}
% timeout 5 gcc-8.0.0-alpha20180218 -O2 -floop-nest-optimize
-fno-tree-copy-prop -fno-tree-fre -fno-tree-loop-ivcanon -c v8gjilr7.c
zsh: exit 124 timeout 5 gcc-8.0.0-alpha20180218 -O2 -floop-nest-optimize
-fno-tree-copy-pro
Two outstanding entries captured by perf top:
61.24% cc1 [.] degenerate_phi_result
38.49% cc1 [.] follow_copies_to_constant
