llvm-project.git/llvm/lib/CodeGen/LiveRegMatrix.cpp, branch main

[CodeGen] Turn MCRegUnit into an enum class (NFC) (#167943)

2025-11-16T17:46:44+00:00

This changes `MCRegUnit` type from `unsigned` to `enum class : unsigned`
and inserts necessary casts.
The added `MCRegUnitToIndex` functor is used with `SparseSet`,
`SparseMultiSet` and `IndexedMap` in a few places.

`MCRegUnit` is opaque to users, so it didn't seem worth making it a
full-fledged class like `Register`.

Static type checking has detected one issue in
`PrologueEpilogueInserter.cpp`, where `BitVector` created for
`MCRegister` is indexed by both `MCRegister` and `MCRegUnit`.

The number of casts could be reduced by using `IndexedMap` in more
places and/or adding a `BitVector` adaptor, but the number of casts *per
file* is still small and `IndexedMap` has limitations, so it didn't seem
worth the effort.

Pull Request: https://github.com/llvm/llvm-project/pull/167943

[CodeGen] Use MCRegUnit in more places (NFC) (#167578)

2025-11-11T22:08:50+00:00

[LiveRegMatrix] Use MCRegUnit instead of MCRegister for register unit. NFC

2025-01-20T18:57:34+00:00

MCRegister should be used for registers, not register units.

[CodeGen] Remove some implict conversions of MCRegister to unsigned by using(). NFC

2025-01-19T21:18:04+00:00

Many of these are indexing BitVectors or something where we can't
using MCRegister and need the register number.

[CodeGen] LiveRegMatrix: Use allocator through a unique_ptr (#120556)

2025-01-01T09:24:08+00:00

`LIU::Matrix` holds on to a pointer to the allocator in LiveRegMatrix and is left hanging when the allocator moves with the LiveRegMatrix.

This extends the lifetime of the allocator so that it does not get destroyed when moving a LiveRegMatrix object.

[CodeGen][PM] Initialize analyses with isAnalysis=true (#118779)

2024-12-06T09:55:54+00:00

Analyses should be marked as analyses.

Otherwise they are prone to get ignored by the legacy analysis cache mechanism and get scheduled redundantly.

VirtRegRewriter: Add implicit register defs for live out undef lanes (#112679)

2024-10-29T00:33:53+00:00

If an undef subregister def is live into another block, we need to
maintain a physreg def to track the liveness of those lanes. This
would manifest a verifier error after branch folding, when the cloned
tail block use no longer had a def.

We need to detect interference with other assigned intervals to avoid
clobbering the undef lanes defined in other intervals, since the undef
def didn't count as interference. This is pretty ugly and adds a new
dependency on LiveRegMatrix, keeping it live for one more pass. It also
adds a lot of implicit operand spam (we really should have a better
representation for this).

There is a missing verifier check for this situation. Added an xfailed
test that demonstrates this. We may also be able to revert the changes
in 47d3cbcf842a036c20c3f1c74255cdfc213f41c2.

It might be better to insert an IMPLICIT_DEF before the instruction
rather than using the implicit-def operand.

Fixes #98474

[NewPM][CodeGen] Port LiveRegMatrix to NPM (#109938)

2024-10-22T09:58:04+00:00

[NewPM][CodeGen] Port VirtRegMap to NPM (#109936)

2024-10-22T09:45:56+00:00

[CodeGen][NewPM] Port `LiveIntervals` to new pass manager (#98118)

2024-07-10T11:34:48+00:00

- Add `LiveIntervalsAnalysis`.
- Add `LiveIntervalsPrinterPass`.
- Use `LiveIntervalsWrapperPass` in legacy pass manager.
- Use `std::unique_ptr` instead of raw pointer for `LICalc`, so
destructor and default move constructor can handle it correctly.

This would be the last analysis required by `PHIElimination`.