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Teach IRCE to look at branch weights when recognizing range checks

Authored by sanjoy on Jan 26 2015, 10:21 PM.



Splitting a loop to make range checks redundant is profitable only if the range check "never" fails. Make this fact a part of recognizing a range check -- a branch is a range check only if it is expected to pass (via branch_weights metadata).

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sanjoy updated this revision to Diff 18796.Jan 26 2015, 10:21 PM
sanjoy retitled this revision from to Teach IRCE to look at branch weights when recognizing range checks.
sanjoy updated this object.
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sanjoy added reviewers: reames, hfinkel.
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hfinkel added inline comments.Jan 27 2015, 6:13 AM
358 ↗(On Diff #18796)

Please don't access the branch_weights metadata directly. Use the BranchProbabilityInfo analysis (which also includes some useful static heuristics).

sanjoy updated this revision to Diff 18845.Jan 27 2015, 12:56 PM

Address Hal's comment and use BranchProbabilityInfo instead of manually parsing branch_weights metadata.

hfinkel accepted this revision.Jan 27 2015, 1:14 PM
hfinkel edited edge metadata.


This revision is now accepted and ready to land.Jan 27 2015, 1:14 PM
This revision was automatically updated to reflect the committed changes.