Commit Graph

8 Commits

Author SHA1 Message Date
Dan Gohman
584fedf188 Teach two-address lowering how to unfold a load to open up commuting
opportunities. For example, this lets it emit this:

   movq (%rax), %rcx
   addq %rdx, %rcx

instead of this:

   movq %rdx, %rcx
   addq (%rax), %rcx

in the case where %rdx has subsequent uses. It's the same number
of instructions, and usually the same encoding size on x86, but
it appears faster, and in general, it may allow better scheduling
for the load.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@106493 91177308-0d34-0410-b5e6-96231b3b80d8
2010-06-21 22:17:20 +00:00
Dan Gohman
1e3121c80a Include the use kind along with the expression in the key of the
use sharing map. The reconcileNewOffset logic already forces a
separate use if the kinds differ, so incorporating the kind in the
key means we can track more sharing opportunities.

More sharing means fewer total uses to track, which means smaller
problem sizes, which means the conservative throttles don't kick
in as often.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@106396 91177308-0d34-0410-b5e6-96231b3b80d8
2010-06-19 21:29:59 +00:00
Dan Gohman
9f23dee08c Start function numbering at 0.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@101638 91177308-0d34-0410-b5e6-96231b3b80d8
2010-04-17 16:29:15 +00:00
Evan Cheng
bdc652bab8 Turning off post-ra scheduling for x86. It isn't a consistent win.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@98810 91177308-0d34-0410-b5e6-96231b3b80d8
2010-03-18 06:55:42 +00:00
Dan Gohman
1b7bf18def When determining the set of interesting reuse factors, consider
strides in foreign loops. This helps locate reuse opportunities
with existing induction variables in foreign loops and reduces
the need for inserting new ones. This fixes rdar://7657764.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@96629 91177308-0d34-0410-b5e6-96231b3b80d8
2010-02-19 00:05:23 +00:00
Dan Gohman
572645cf84 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.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@95975 91177308-0d34-0410-b5e6-96231b3b80d8
2010-02-12 10:34:29 +00:00
Dan Gohman
7979b72feb Revert LoopStrengthReduce.cpp to pre-r94061 for now.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@94123 91177308-0d34-0410-b5e6-96231b3b80d8
2010-01-22 00:46:49 +00:00
Dan Gohman
a10756ee65 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.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@94061 91177308-0d34-0410-b5e6-96231b3b80d8
2010-01-21 02:09:26 +00:00