This is helpful for tests with a lot of test cases and grepping for
instructions with missing profile data isn't feasible because it doesn't
account for things like vectors which are exempt.
Tracking issue: #147390
Functions listed in `llvm.global_ctors` or `llvm.global_dtors` aren't too interesting for performance. Passes like LowerTypeTests synthesize some of these, and, while we could add a "0" entry count explicitly, we can also just not bother verifying in the first place.
There are cases where the easiest way to regression-test a profile change is to add `!prof` metadata, with small numbers as to simplify manual verification. To ensure coverage, this (the inserting) may become tedious. This patch makes `prof-inject` do that for us, if so opted in.
The list of weights used is a bunch of primes, used as a circular buffer.
Issue #147390
Some passes synthesize functions, e.g. WPD, so we may need to indicate “this synthesized function’s entry count cannot be estimated at compile time” - akin to `branch_weights`.
Issue #147390
These are identified by misc-include-cleaner. I've filtered out those
that break builds. Also, I'm staying away from llvm-config.h,
config.h, and Compiler.h, which likely cause platform- or
compiler-specific build failures.
For `select`, we don't have the equivalent of the branch probability analysis to offer defaults, so we make up our own and allow their overriding with flags.
Issue #147390
There is a case when branch profile metadata is OK to miss, namely, cold functions. The goal of the RFC (see the referenced issue) is to avoid accidental omission (and, at a later date, corruption) of profile metadata. However, asking cold functions to have all their conditional branches marked with "0" probabilities would be overdoing it. We can just ask cold functions to have an explicit 0 entry count.
This patch:
- injects an entry count for functions, unless they have one (synthetic or not)
- if the entry count is 0, doesn't inject, nor does it verify the rest of the metadata
- at verification, if the entry count is missing, it reports an error
Issue #147390
Adding 2 passes, one to inject `MD_prof` and one to check its presence. A subsequent patch will add these (similar to debugify) to `opt` (and, eventually, a variant of this, to `llc`)
Tracking issue: #147390
