Commit Graph

8 Commits

Author SHA1 Message Date
Jakob Stoklund Olesen
b1c0cc22dd Print block frequencies in decimal form.
This is easier to read than the internal fixed-point representation.

If anybody knows the correct algorithm for converting fixed-point
numbers to base 10, feel free to fix it.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@184881 91177308-0d34-0410-b5e6-96231b3b80d8
2013-06-25 21:57:38 +00:00
Benjamin Kramer
75b5162154 BlockFrequency: Bump up the entry frequency a bit.
This is a band-aid to fix the most severe regressions we're seeing from basing
spill decisions on block frequencies, until we have a better solution.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@184835 91177308-0d34-0410-b5e6-96231b3b80d8
2013-06-25 13:34:40 +00:00
Benjamin Kramer
b47aceaf06 Revert "BlockFrequency: Saturate at 1 instead of 0 when multiplying a frequency with a branch probability."
This reverts commit r184584. Breaks PPC selfhost.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@184590 91177308-0d34-0410-b5e6-96231b3b80d8
2013-06-21 20:20:27 +00:00
Benjamin Kramer
93702a3b07 BlockFrequency: Saturate at 1 instead of 0 when multiplying a frequency with a branch probability.
Zero is used by BlockFrequencyInfo as a special "don't know" value. It also
causes a sink for frequencies as you can't ever get off a zero frequency with
more multiplies.

This recovers a 10% regression on MultiSource/Benchmarks/7zip. A zero frequency
was propagated into an inner loop causing excessive spilling.

PR16402.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@184584 91177308-0d34-0410-b5e6-96231b3b80d8
2013-06-21 19:30:05 +00:00
Eli Bendersky
0f0c411079 Replace all instances of dg.exp file with lit.local.cfg, since all tests are run with LIT now and now Dejagnu. dg.exp is no longer needed.
Patch reviewed by Daniel Dunbar. It will be followed by additional cleanup patches.




git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@150664 91177308-0d34-0410-b5e6-96231b3b80d8
2012-02-16 06:28:33 +00:00
Chandler Carruth
941aa7b1e8 Generalize the reading of probability metadata to work for both branches
and switches, with arbitrary numbers of successors. Still optimized for
the common case of 2 successors for a conditional branch.

Add a test case for switch metadata showing up in the BlockFrequencyInfo pass.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@142493 91177308-0d34-0410-b5e6-96231b3b80d8
2011-10-19 10:32:19 +00:00
Chandler Carruth
99d01c54a0 Teach the BranchProbabilityInfo analysis pass to read any metadata
encoding of probabilities. In the absense of metadata, it continues to
fall back on static heuristics.

This allows __builtin_expect, after lowering through llvm.expect
a branch instruction's metadata, to actually enter the branch
probability model. This is one component of resolving PR2577.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@142492 91177308-0d34-0410-b5e6-96231b3b80d8
2011-10-19 10:30:30 +00:00
Chandler Carruth
6aa5c26c81 Add pass printing support to BlockFrequencyInfo pass. The implementation
layer already had support for printing the results of this analysis, but
the wiring was missing.

Now that printing the analysis works, actually bring some of this
analysis, and the BranchProbabilityInfo analysis that it wraps, under
test! I'm planning on fixing some bugs and doing other work here, so
having a nice place to add regression tests and a way to observe the
results is really useful.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@142491 91177308-0d34-0410-b5e6-96231b3b80d8
2011-10-19 10:12:41 +00:00