Restrict call metadata based hotness detection to Sample PGO mode

Description

Restrict call metadata based hotness detection to Sample PGO mode

Summary:
Don't use the metadata on call instructions for determining hotness
unless we are in sample PGO mode, where it is needed because profile
counts are not accurate. In instrumentation mode this is not necessary
and does more harm than good when calls have VP metadata that hasn't
been properly scaled after transformations or dropped after constant
prop based devirtualization (both should be fixed, but we don't need
to do this in the first place for instrumentation PGO).

This required adjusting a number of tests to distinguish between sample
and instrumentation PGO handling, and to add in profile summary metadata
so that getProfileCount can get the summary.

Reviewers: davidxl, danielcdh

Subscribers: aemerson, rengolin, mehdi_amini, Prazek, llvm-commits

Differential Revision: https://reviews.llvm.org/D32877

Details

Committed
tejohnsonMay 11 2017, 4:18 PM
Differential Revision
D32877: Restrict call metadata based hotness detection to Sample PGO mode
Parents
rL302843: Reduce templating. NFC.
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