[Bug middle-end/49310] [4.7 Regression] Compile time hog in var-tracking emit

[Joost.VandeVondele at pci dot uzh.ch]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49310

--- Comment #2 from Joost VandeVondele <Joost.VandeVondele at pci dot uzh.ch> 
2011-06-08 07:16:06 UTC ---
the testcase from 

http://gcc.gnu.org/bugzilla/attachment.cgi?id=20290

can be used more conveniently. It runs in 1.4s and still spends 50% of time in
var-tracking emit. 

Using callgrind, most of the time is in emit_notes_for_changes, calling
htab_traverse.