diff options
| author | bors <bors@rust-lang.org> | 2023-12-30 03:45:58 +0000 |
|---|---|---|
| committer | bors <bors@rust-lang.org> | 2023-12-30 03:45:58 +0000 |
| commit | 8d76d076665f862ec9619f2de68d6d9ca1db4601 (patch) | |
| tree | e8e677eac08c9779819b5c046d8ee9c1d2b37f68 /compiler/rustc_mir_transform/src/errors.rs | |
| parent | 03b50195ab61a0dc9fc8de43d1de92769c4e6f23 (diff) | |
| parent | 6d7f0632ede023c71ebcd03c791166c716273b20 (diff) | |
| download | rust-8d76d076665f862ec9619f2de68d6d9ca1db4601.tar.gz rust-8d76d076665f862ec9619f2de68d6d9ca1db4601.zip | |
Auto merge of #116012 - cjgillot:gvn-const, r=oli-obk
Implement constant propagation on top of MIR SSA analysis This implements the idea I proposed in https://github.com/rust-lang/rust/pull/110719#issuecomment-1718324700 Based on https://github.com/rust-lang/rust/pull/109597 The value numbering "GVN" pass formulates each rvalue that appears in MIR with an abstract form (the `Value` enum), and assigns an integer `VnIndex` to each. This abstract form can be used to deduplicate values, reusing an earlier local that holds the same value instead of recomputing. This part is proposed in #109597. From this abstract representation, we can perform more involved simplifications, for example in https://github.com/rust-lang/rust/pull/111344. With the abstract representation `Value`, we can also attempt to evaluate each to a constant using the interpreter. This builds a `VnIndex -> OpTy` map. From this map, we can opportunistically replace an operand or a rvalue with a constant if their value has an associated `OpTy`. The most relevant commit is [Evaluated computed values to constants.](https://github.com/rust-lang/rust/commit/2767c4912ea249c2f613a9cedcd6c13ea1237e54)" r? `@oli-obk`
Diffstat (limited to 'compiler/rustc_mir_transform/src/errors.rs')
0 files changed, 0 insertions, 0 deletions