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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-05-30 03:59:35 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-05-30 03:59:35 +0000 |
commit | d1b2d29528b7794b41e66fc2136e395a02f8529b (patch) | |
tree | a4a17504b260206dec3cf55b2dca82929a348ac2 /compiler/rustc_mir_transform/src/dead_store_elimination.rs | |
parent | Releasing progress-linux version 1.72.1+dfsg1-1~progress7.99u1. (diff) | |
download | rustc-d1b2d29528b7794b41e66fc2136e395a02f8529b.tar.xz rustc-d1b2d29528b7794b41e66fc2136e395a02f8529b.zip |
Merging upstream version 1.73.0+dfsg1.
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'compiler/rustc_mir_transform/src/dead_store_elimination.rs')
-rw-r--r-- | compiler/rustc_mir_transform/src/dead_store_elimination.rs | 40 |
1 files changed, 38 insertions, 2 deletions
diff --git a/compiler/rustc_mir_transform/src/dead_store_elimination.rs b/compiler/rustc_mir_transform/src/dead_store_elimination.rs index 7bc5183a0..3f988930b 100644 --- a/compiler/rustc_mir_transform/src/dead_store_elimination.rs +++ b/compiler/rustc_mir_transform/src/dead_store_elimination.rs @@ -13,9 +13,12 @@ //! use rustc_index::bit_set::BitSet; +use rustc_middle::mir::visit::Visitor; use rustc_middle::mir::*; use rustc_middle::ty::TyCtxt; -use rustc_mir_dataflow::impls::{borrowed_locals, MaybeTransitiveLiveLocals}; +use rustc_mir_dataflow::impls::{ + borrowed_locals, LivenessTransferFunction, MaybeTransitiveLiveLocals, +}; use rustc_mir_dataflow::Analysis; /// Performs the optimization on the body @@ -28,8 +31,33 @@ pub fn eliminate<'tcx>(tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>, borrowed: &BitS .iterate_to_fixpoint() .into_results_cursor(body); + // For blocks with a call terminator, if an argument copy can be turned into a move, + // record it as (block, argument index). + let mut call_operands_to_move = Vec::new(); let mut patch = Vec::new(); + for (bb, bb_data) in traversal::preorder(body) { + if let TerminatorKind::Call { ref args, .. } = bb_data.terminator().kind { + let loc = Location { block: bb, statement_index: bb_data.statements.len() }; + + // Position ourselves between the evaluation of `args` and the write to `destination`. + live.seek_to_block_end(bb); + let mut state = live.get().clone(); + + for (index, arg) in args.iter().enumerate().rev() { + if let Operand::Copy(place) = *arg + && !place.is_indirect() + && !borrowed.contains(place.local) + && !state.contains(place.local) + { + call_operands_to_move.push((bb, index)); + } + + // Account that `arg` is read from, so we don't promote another argument to a move. + LivenessTransferFunction(&mut state).visit_operand(arg, loc); + } + } + for (statement_index, statement) in bb_data.statements.iter().enumerate().rev() { let loc = Location { block: bb, statement_index }; if let StatementKind::Assign(assign) = &statement.kind { @@ -64,7 +92,7 @@ pub fn eliminate<'tcx>(tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>, borrowed: &BitS } } - if patch.is_empty() { + if patch.is_empty() && call_operands_to_move.is_empty() { return; } @@ -72,6 +100,14 @@ pub fn eliminate<'tcx>(tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>, borrowed: &BitS for Location { block, statement_index } in patch { bbs[block].statements[statement_index].make_nop(); } + for (block, argument_index) in call_operands_to_move { + let TerminatorKind::Call { ref mut args, .. } = bbs[block].terminator_mut().kind else { + bug!() + }; + let arg = &mut args[argument_index]; + let Operand::Copy(place) = *arg else { bug!() }; + *arg = Operand::Move(place); + } crate::simplify::simplify_locals(body, tcx) } |