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author | Camille GILLOT <gillot.camille@gmail.com> | 2023-05-14 12:10:24 +0000 |
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committer | Camille GILLOT <gillot.camille@gmail.com> | 2023-05-14 12:10:24 +0000 |
commit | adfffc7e123a0cca1fefdfc48a7c7860a428c7f4 (patch) | |
tree | a9a730accd4af3a6c629b020e4bc71339314465b | |
parent | f40f23587993a3f1afd1405cbcc56bc4324dd378 (diff) | |
download | rust-adfffc7e123a0cca1fefdfc48a7c7860a428c7f4.tar.gz |
Simplify implementation.
-rw-r--r-- | compiler/rustc_mir_transform/src/ssa.rs | 38 |
1 files changed, 16 insertions, 22 deletions
diff --git a/compiler/rustc_mir_transform/src/ssa.rs b/compiler/rustc_mir_transform/src/ssa.rs index e5877feb8b2..2b404efccc7 100644 --- a/compiler/rustc_mir_transform/src/ssa.rs +++ b/compiler/rustc_mir_transform/src/ssa.rs @@ -101,14 +101,15 @@ impl SsaLocals { .retain(|&local| matches!(visitor.assignments[local], Set1::One(_))); debug!(?visitor.assignment_order); - let copy_classes = compute_copy_classes(&mut visitor, body); - - SsaLocals { + let mut ssa = SsaLocals { assignments: visitor.assignments, assignment_order: visitor.assignment_order, direct_uses: visitor.direct_uses, - copy_classes, - } + // This is filled by `compute_copy_classes`. + copy_classes: IndexVec::default(), + }; + compute_copy_classes(&mut ssa, body); + ssa } pub fn num_locals(&self) -> usize { @@ -261,27 +262,19 @@ impl<'tcx> Visitor<'tcx> for SsaVisitor { } #[instrument(level = "trace", skip(ssa, body))] -fn compute_copy_classes(ssa: &mut SsaVisitor, body: &Body<'_>) -> IndexVec<Local, Local> { +fn compute_copy_classes(ssa: &mut SsaLocals, body: &Body<'_>) { + let mut direct_uses = std::mem::take(&mut ssa.direct_uses); let mut copies = IndexVec::from_fn_n(|l| l, body.local_decls.len()); - for &local in &ssa.assignment_order { - debug!(?local); - - // This is not SSA: mark that we don't know the value. - debug!(assignments = ?ssa.assignments[local]); - let Set1::One(LocationExtended::Plain(loc)) = ssa.assignments[local] else { continue }; - - // `loc` must point to a direct assignment to `local`. - let Either::Left(stmt) = body.stmt_at(loc) else { bug!() }; - let Some((_target, rvalue)) = stmt.kind.as_assign() else { bug!() }; - assert_eq!(_target.as_local(), Some(local)); - + for (local, rvalue, _) in ssa.assignments(body) { let (Rvalue::Use(Operand::Copy(place) | Operand::Move(place)) | Rvalue::CopyForDeref(place)) = rvalue else { continue }; let Some(rhs) = place.as_local() else { continue }; - let Set1::One(_) = ssa.assignments[rhs] else { continue }; + if !ssa.is_ssa(rhs) { + continue; + } // We visit in `assignment_order`, ie. reverse post-order, so `rhs` has been // visited before `local`, and we just have to copy the representing local. @@ -302,11 +295,11 @@ fn compute_copy_classes(ssa: &mut SsaVisitor, body: &Body<'_>) -> IndexVec<Local } else { copies[local] = head; } - ssa.direct_uses[rhs] -= 1; + direct_uses[rhs] -= 1; } debug!(?copies); - debug!(?ssa.direct_uses); + debug!(?direct_uses); // Invariant: `copies` must point to the head of an equivalence class. #[cfg(debug_assertions)] @@ -315,7 +308,8 @@ fn compute_copy_classes(ssa: &mut SsaVisitor, body: &Body<'_>) -> IndexVec<Local } debug_assert_eq!(copies[RETURN_PLACE], RETURN_PLACE); - copies + ssa.direct_uses = direct_uses; + ssa.copy_classes = copies; } #[derive(Debug)] |