From 626422dff642fa52b35158550a44d9e3a4627de9 Mon Sep 17 00:00:00 2001
From: Andreas Kloeckner <inform@tiker.net>
Date: Tue, 10 May 2016 11:55:29 -0500
Subject: [PATCH] Add explanation to regression test for #24
---
test/test_loopy.py | 10 +++++++++-
1 file changed, 9 insertions(+), 1 deletion(-)
diff --git a/test/test_loopy.py b/test/test_loopy.py
index 1205d209a..f7ef0db33 100644
--- a/test/test_loopy.py
+++ b/test/test_loopy.py
@@ -2491,9 +2491,17 @@ def test_clamp(ctx_factory):
def test_forced_iname_deps_and_reduction():
+ # See https://github.com/inducer/loopy/issues/24
+
+ # This is (purposefully) somewhat un-idiomatic, to replicate the conditions
+ # under which the above bug was found. If assignees were phi[i], then the
+ # iname propagation heuristic would not assume that dependent instructions
+ # need to run inside of 'i', and hence the forced_iname_* bits below would not
+ # be needed.
+
i1 = lp.CInstruction("i",
"doSomethingToGetPhi();",
- assignees=frozenset({"phi"}))
+ assignees="phi")
from pymbolic.primitives import Subscript, Variable
i2 = lp.Assignment("a",
--
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