bjoernager/rust
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Abstract out has_back_edge fn

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This commit is contained in:
Bryan Garza 2022-12-29 19:37:33 +00:00
parent 009beb00bc
commit 8d99b0fc8d
1 changed files with 28 additions and 23 deletions
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35
compiler/rustc_mir_transform/src/ctfe_limit.rs
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@ -1,7 +1,7 @@
use crate::MirPass; use crate::MirPass;
use rustc_middle::mir::{ use rustc_middle::mir::{
BasicBlock, BasicBlockData, Body, Statement, StatementKind, TerminatorKind, BasicBlock, BasicBlockData, BasicBlocks, Body, Statement, StatementKind, TerminatorKind,
}; };
use rustc_middle::ty::TyCtxt; use rustc_middle::ty::TyCtxt;
@ -10,23 +10,14 @@ pub struct CtfeLimit;
impl<'tcx> MirPass<'tcx> for CtfeLimit { impl<'tcx> MirPass<'tcx> for CtfeLimit {
#[instrument(skip(self, _tcx, body))] #[instrument(skip(self, _tcx, body))]
fn run_pass(&self, _tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) { fn run_pass(&self, _tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {
let doms = body.basic_blocks.dominators(); let indices: Vec<BasicBlock> = body
let indices: Vec<BasicBlock> = .basic_blocks
body.basic_blocks
.iter_enumerated() .iter_enumerated()
.filter_map(|(node, node_data)| { .filter_map(|(node, node_data)| {
if matches!(node_data.terminator().kind, TerminatorKind::Call { .. }) || if matches!(node_data.terminator().kind, TerminatorKind::Call { .. })
// Back edges in a CFG indicate loops // Back edges in a CFG indicate loops
body.basic_blocks.iter_enumerated().any(|(potential_dom, _)| { || has_back_edge(&body.basic_blocks, node, &node_data)
doms.is_reachable(potential_dom) {
&& doms.is_reachable(node)
&& doms.is_dominated_by(node, potential_dom)
&& node_data
.terminator()
.successors()
.into_iter()
.any(|succ| succ == potential_dom)
}) {
Some(node) Some(node)
} else { } else {
None None
@ -43,6 +34,20 @@ impl<'tcx> MirPass<'tcx> for CtfeLimit {
} }
} }
fn has_back_edge(
basic_blocks: &BasicBlocks<'_>,
node: BasicBlock,
node_data: &BasicBlockData<'_>,
) -> bool {
let doms = basic_blocks.dominators();
basic_blocks.indices().any(|potential_dom| {
doms.is_reachable(potential_dom)
&& doms.is_reachable(node)
&& doms.is_dominated_by(node, potential_dom)
&& node_data.terminator().successors().into_iter().any(|succ| succ == potential_dom)
})
}
fn insert_counter(basic_block_data: &mut BasicBlockData<'_>) { fn insert_counter(basic_block_data: &mut BasicBlockData<'_>) {
basic_block_data.statements.push(Statement { basic_block_data.statements.push(Statement {
source_info: basic_block_data.terminator().source_info, source_info: basic_block_data.terminator().source_info,