[Bug middle-end/64928] [4.8/4.9/5 Regression] Inordinate cpu time and memory usage in "phase opt and generate" with -ftest-coverage -fprofile-arcs

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64928

--- Comment #17 from Richard Biener <rguenth at gcc dot gnu.org> ---
Created attachment 34975
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=34975&action=edit
do not compute live/conflict for abnormal coalesces

This is the other idea of simply not computing live/conflict for abnormal
coalesces we know to always succeed.  This shrinks the following live/conflict
problem for the regular coalesces by unifying some partitions.

Doesn't help this particular testcase much.