http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58478
Richard Biener <rguenth at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Keywords| |compile-time-hog
Component|middle-end |tree-optimization
--- Comment #3 from Richard Biener <rguenth at gcc dot gnu.org> ---
A lot of work was spent to make GCC faster in corner-cases for GCC 4.8 (and
4.9).
This bug triggers
tree reassociation : 18.28 (96%) usr 0.05 (15%) sys 18.37 (94%) wall
2047 kB ( 3%) ggc
which means it's likely gsi_for_stmt becoming O(1) in 4.8 vs being O(n) in 4.7
and the loops being completely unrollend (and thus larger BBs). Indeed
the final cunroll pass unrolls the loop nest completely, leaving a basic-block
with ~166000 instructions and no constant propagation before it (sth 4.8
improved on as well).
I'd say WONTFIX and move on to 4.8.
