tree 642cb6b52f68e4e6d03475e80dc2845c5e4f50f6
parent 0d7398fd5407938aba75c50bd323af27e83ccb9f
author Aart Bik <ajcbik@google.com> 1476139150 -0700
committer Aart Bik <ajcbik@google.com> 1476207582 -0700

Improved and simplified loop optimizations.

Rationale:
Empty preheader simplification has been simplified
to a much more general empty block removal optimization
step. Incremental updating of induction variable
analysis enables repeated elimination or simplification
of induction cycles.

This enabled an extra layer of optimization for
e.g. Benchpress Loop (17.5us. -> 0.24us. -> 0.08us).
So the original 73x speedup is now multiplied
by another 3x, for a total of about 218x.

Test: 618-checker-induction et al.
Change-Id: I394699981481cdd5357e0531bce88cd48bd32879