Commit Graph

4 Commits

Author SHA1 Message Date
Dan Gohman
45774ce0ad Reapply the new LoopStrengthReduction code, with compile time and
bug fixes, and with improved heuristics for analyzing foreign-loop
addrecs.

This change also flattens IVUsers, eliminating the stride-oriented
groupings, which makes it easier to work with.

llvm-svn: 95975
2010-02-12 10:34:29 +00:00
Dan Gohman
045f81981a Revert LoopStrengthReduce.cpp to pre-r94061 for now.
llvm-svn: 94123
2010-01-22 00:46:49 +00:00
Dan Gohman
51ad99d2c5 Re-implement the main strength-reduction portion of LoopStrengthReduction.
This new version is much more aggressive about doing "full" reduction in
cases where it reduces register pressure, and also more aggressive about
rewriting induction variables to count down (or up) to zero when doing so
reduces register pressure.

It currently uses fairly simplistic algorithms for finding reuse
opportunities, but it introduces a new framework allows it to combine
multiple strategies at once to form hybrid solutions, instead of doing
all full-reduction or all base+index.

llvm-svn: 94061
2010-01-21 02:09:26 +00:00
Evan Cheng
87fe40b32d Generalize lsr code that optimize loop to count down towards zero.
llvm-svn: 86715
2009-11-10 21:14:05 +00:00