From b99128b7c54bf91e4dc71eff34967a7e0abb2595 Mon Sep 17 00:00:00 2001
From: Xavier Routh <xrouth2@illinois.edu>
Date: Fri, 14 Feb 2025 10:37:54 -0600
Subject: [PATCH] forkify more aggressively
---
hercules_opt/src/forkify.rs | 50 +++++++------------------------------
1 file changed, 9 insertions(+), 41 deletions(-)
diff --git a/hercules_opt/src/forkify.rs b/hercules_opt/src/forkify.rs
index 774220df..0bfe152a 100644
--- a/hercules_opt/src/forkify.rs
+++ b/hercules_opt/src/forkify.rs
@@ -183,8 +183,7 @@ pub fn forkify_loop(
let reductionable_phis: Vec<_> = analyze_phis(&editor, &l, &candidate_phis, &loop_nodes)
.into_iter()
.collect();
- // TODO: Handle multiple loop body lasts.
- // If there are multiple candidates for loop body last, return false.
+
if editor
.get_uses(loop_if)
.filter(|id| l.control[id.idx()])
@@ -417,9 +416,9 @@ nest! {
continue_latch: NodeID,
is_associative: bool,
},
- LoopDependant(NodeID),
- ControlDependant(NodeID), // This phi is redcutionable, but its cycle might depend on internal control within the loop.
- UsedByDependant(NodeID),
+ OutsideUse(NodeID),
+ NonCyclic(NodeID),
+
}
}
@@ -427,9 +426,8 @@ impl LoopPHI {
pub fn get_phi(&self) -> NodeID {
match self {
LoopPHI::Reductionable { phi, .. } => *phi,
- LoopPHI::LoopDependant(node_id) => *node_id,
- LoopPHI::UsedByDependant(node_id) => *node_id,
- LoopPHI::ControlDependant(node_id) => *node_id,
+ LoopPHI::OutsideUse(node_id) => *node_id,
+ LoopPHI::NonCyclic(node_id) => *node_id,
}
}
}
@@ -500,42 +498,12 @@ pub fn analyze_phis<'a>(
let uses = walk_all_uses_stop_on(loop_continue_latch, editor, stop_on.clone());
let users = walk_all_users_stop_on(*phi, editor, stop_on.clone());
- let other_stop_on: HashSet<NodeID> = editor
- .node_ids()
- .filter(|node| {
- let data = &editor.func().nodes[node.idx()];
-
- // Phi, Reduce
- if data.is_phi() {
- return true;
- }
-
- if data.is_reduce() {
- return true;
- }
-
- // External Control
- if data.is_control() {
- return true;
- }
-
- return false;
- })
- .collect();
-
- let mut uses_for_dependance =
- walk_all_users_stop_on(loop_continue_latch, editor, other_stop_on);
-
let set1: HashSet<_> = HashSet::from_iter(uses);
let set2: HashSet<_> = HashSet::from_iter(users);
let intersection: HashSet<_> = set1.intersection(&set2).cloned().collect();
- // If this phi uses any other phis the node is loop dependant,
- // we use `phis` because this phi can actually contain the loop iv and its fine.
- if uses_for_dependance.any(|node| phis.contains(&node) && node != *phi) {
- LoopPHI::LoopDependant(*phi)
- } else if intersection.clone().iter().next().is_some() {
+ if intersection.clone().iter().next().is_some() {
// PHIs on the frontier of the uses by the candidate phi, i.e in uses_for_dependance need
// to have headers that postdominate the loop continue latch. The value of the PHI used needs to be defined
// by the time the reduce is triggered (at the end of the loop's internal control).
@@ -555,7 +523,7 @@ pub fn analyze_phis<'a>(
// 3) Split the cycle into two phis, add them or multiply them together at the end.
// 4) Split the cycle into two reduces, add them or multiply them together at the end.
// Somewhere else should handle this.
- return LoopPHI::LoopDependant(*phi);
+ return LoopPHI::OutsideUse(*phi);
}
// FIXME: Do we want to calculate associativity here, there might be a case where this information is used in forkify
@@ -571,7 +539,7 @@ pub fn analyze_phis<'a>(
}
} else {
// No cycles exist, this isn't a reduction.
- LoopPHI::LoopDependant(*phi)
+ LoopPHI::NonCyclic(*phi)
}
})
}
--
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