History log of /llvm-project/llvm/test/Transforms/SampleProfile/pseudo-probe-invoke.ll (Results 1 – 2 of 2)
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Revision tags: llvmorg-18.1.8, llvmorg-18.1.7, llvmorg-18.1.6, llvmorg-18.1.5, llvmorg-18.1.4
# 5bbce06a 03-Apr-2024 Lei Wang <wlei@fb.com>

[PseudoProbe] Mix block and call probe ID in lexical order (#75092)

Before all the call probe ids are after block ids, in this change, it
mixed the call probe and block probe by reordering them in

[PseudoProbe] Mix block and call probe ID in lexical order (#75092)

Before all the call probe ids are after block ids, in this change, it
mixed the call probe and block probe by reordering them in
lexical(line-number) order. For example:
```
main():
BB1
if(...)
BB2 foo(..);
else
BB3 bar(...);
BB4
```
Before the profile is
```
main
1: ..
2: ..
3: ...
4: ...
5: foo ...
6: bar ...
```
Now the new order is
```
main
1: ..
2: ..
3: foo ...
4: ...
5: bar ...
6: ...
```
This can potentially make it more tolerant of profile mismatch, either from stale profile or frontend change. e.g. before if we add one block, even the block is the last one, all the call probes are shifted and mismatched. Moreover, this makes better use of call-anchor based stale profile matching. Blocks are matched based on the closest anchor, there would be more anchors used for the matching, reduce the mismatch scope.

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Revision tags: llvmorg-18.1.3
# b8cc3ba4 01-Apr-2024 Lei Wang <wlei@fb.com>

[PseudoProbe] Extend to skip instrumenting probe into the dests of invoke (#79919)

As before we only skip instrumenting probe of `unwind`(`KnownColdBlock`)
block, this PR extends to skip the both E

[PseudoProbe] Extend to skip instrumenting probe into the dests of invoke (#79919)

As before we only skip instrumenting probe of `unwind`(`KnownColdBlock`)
block, this PR extends to skip the both EH flow from `invoke`, i.e. also
skip the `normal` dest. For more contexts: when doing call-to-invoke
conversion, the block is split by the `invoke` and two extra
blocks(`normal` and `unwind`) are added. With this PR, the
instrumentation is the same as the one before the call-to-invoke
conversion.
One significant benefit is this can help mitigate the "unstable IR"
issue(https://discourse.llvm.org/t/ipo-for-linkonce-odr-functions/69404),
the two versions now are on the same probe instrumentation, expected to
be the same checksum.
To achieve the same checksum, some tweaks is needed:
- Now it also skips incrementing the probe ID for the skipped probe.
- The checksum is also computed based on the CFG that skips the EH
edges.

We observed this fixes ~5% mismatched samples.

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