From 8aabec77960f670699491ed1214bdb44b0c9ccf7 Mon Sep 17 00:00:00 2001
From: Xavier Routh <xrouth2@illinois.edu>
Date: Thu, 30 Jan 2025 09:34:14 -0600
Subject: [PATCH] better phi reduce condition
---
hercules_opt/src/forkify.rs | 23 ++++++++++++++---------
1 file changed, 14 insertions(+), 9 deletions(-)
diff --git a/hercules_opt/src/forkify.rs b/hercules_opt/src/forkify.rs
index abd0aaca..f3ce186e 100644
--- a/hercules_opt/src/forkify.rs
+++ b/hercules_opt/src/forkify.rs
@@ -477,10 +477,17 @@ pub fn analyze_phis<'a>(
return false;
})
.collect();
+
+ let continue_idx = editor
+ .get_uses(natural_loop.header)
+ .position(|node| natural_loop.control[node.idx()])
+ .unwrap();
+
+ let loop_continue_latch = editor.node(phi).try_phi().unwrap().1[continue_idx];
// TODO: We may need to stop on exiting the loop for looking for data cycles.
- let uses = walk_all_uses_stop_on(*phi, editor, stop_on.clone());
- let users = walk_all_users_stop_on(*phi, editor, stop_on.clone());
+ let uses = walk_all_uses_stop_on(loop_continue_latch, editor, stop_on.clone());
+ let users = walk_all_users_stop_on(loop_continue_latch, editor, stop_on.clone());
let other_stop_on: HashSet<NodeID> = editor
.node_ids()
@@ -509,8 +516,10 @@ pub fn analyze_phis<'a>(
return false;
})
.collect();
+
+
- let mut uses_for_dependance = walk_all_users_stop_on(*phi, editor, other_stop_on);
+ 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);
@@ -523,12 +532,7 @@ pub fn analyze_phis<'a>(
LoopPHI::LoopDependant(*phi)
}
else if intersection.clone().iter().any(|node| true) {
- let continue_idx = editor
- .get_uses(natural_loop.header)
- .position(|node| natural_loop.control[node.idx()])
- .unwrap();
- let loop_continue_latch = editor.node(phi).try_phi().unwrap().1[continue_idx];
// 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
@@ -538,7 +542,8 @@ pub fn analyze_phis<'a>(
// If some other node in the cycle is used, there is not a valid node to assign it after making the cycle a reduce.
if intersection
.iter()
- .filter(|node| **node != loop_continue_latch)
+ .filter(|node| **node != loop_continue_latch )
+ .filter(|node| !(editor.node(*node).is_reduce() || editor.node(*node).is_phi()))
.any(|data_node| {
editor
.get_users(*data_node)
--
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