From b67689d5a7c5dd6e62106c55e12ccbeb46c94076 Mon Sep 17 00:00:00 2001
From: Matt Wala <wala1@illinois.edu>
Date: Fri, 7 Apr 2017 02:35:39 -0500
Subject: [PATCH] Actually get rid of the need for recursive_insn_dep_map().
---
loopy/kernel/__init__.py | 52 ++++++++++++++++++++++++++++++++--------
1 file changed, 42 insertions(+), 10 deletions(-)
diff --git a/loopy/kernel/__init__.py b/loopy/kernel/__init__.py
index a7b358698..15084df7e 100644
--- a/loopy/kernel/__init__.py
+++ b/loopy/kernel/__init__.py
@@ -839,6 +839,11 @@ class LoopKernel(ImmutableRecordWithoutPickling):
unvisited = set(insn.id for insn in self.instructions)
+ def is_barrier(my_insn_id):
+ insn = self.id_to_insn[my_insn_id]
+ from loopy.kernel.instruction import BarrierInstruction
+ return isinstance(insn, BarrierInstruction) and insn.kind == "global"
+
while unvisited:
stack = [unvisited.pop()]
@@ -847,12 +852,8 @@ class LoopKernel(ImmutableRecordWithoutPickling):
if top in visiting:
visiting.remove(top)
-
- from loopy.kernel.instruction import BarrierInstruction
- insn = self.id_to_insn[top]
- if isinstance(insn, BarrierInstruction):
- if insn.kind == "global":
- barriers.append(top)
+ if is_barrier(top):
+ barriers.append(top)
if top in visited:
stack.pop()
@@ -867,11 +868,42 @@ class LoopKernel(ImmutableRecordWithoutPickling):
stack.append(child)
# Ensure this is the only possible order.
+ #
+ # We do this by looking at the barriers in order.
+ # We check for each adjacent pair (a,b) in the order if a < b,
+ # i.e. if a is reachable by a chain of dependencies from b.
+
+ visiting.clear()
+ visited.clear()
+
for prev_barrier, barrier in zip(barriers, barriers[1:]):
- if prev_barrier not in self.recursive_insn_dep_map()[barrier]:
- raise LoopyError(
- "Unordered global barriers detected: '%s', '%s'"
- % (barrier, prev_barrier))
+ # Check if prev_barrier is reachable from barrier.
+ stack = [barrier]
+ visited.discard(prev_barrier)
+
+ while stack:
+ top = stack[-1]
+
+ if top in visiting:
+ visiting.remove(top)
+
+ if top in visited:
+ stack.pop()
+ continue
+
+ visited.add(top)
+ visiting.add(top)
+
+ if top == prev_barrier:
+ visiting.clear()
+ break
+
+ for child in self.id_to_insn[top].depends_on:
+ stack.append(child)
+ else:
+ # Search exhausted and we did not find prev_barrier.
+ raise LoopyError("barriers '%s' and '%s' are not ordered"
+ % (prev_barrier, barrier))
return tuple(barriers)
--
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