http://gcc.gnu.org/bugzilla/show_bug.cgi?id=48141
Summary: [4.4/4.5/4.6/4.7 Regression] DSE compile time hog
Product: gcc
Version: 4.6.0
Status: UNCONFIRMED
Keywords: compile-time-hog
Severity: normal
Priority: P3
Component: rtl-optimization
AssignedTo: ja...@gcc.gnu.org
ReportedBy: ja...@gcc.gnu.org
#define A i = 0;
#define B A A A A A A A A A A
#define C B B B B B B B B B B
#define D C C C C C C C C C C
#define E D D D D D D D D D D
int
foo (void)
{
volatile int i = 0;
E E E E E E E E E E E
return 0;
}
compiles at -O in under 4 seconds in 4.3, but in 4.4+ takes almost 8 minutes,
99% of the time spent in RTL DSE, and as it is quadratic, trying 10 times as
many stores makes things much worse.
