From ef38e8d058f34f593b00e7562ef0cc45dfc7f29a Mon Sep 17 00:00:00 2001
From: Andreas Kloeckner <inform@tiker.net>
Date: Sun, 19 Apr 2015 13:35:33 -0500
Subject: [PATCH] Detect whether buffered arrays are written, and only emit
store insn if so
---
loopy/buffer.py | 13 ++++++++++++-
1 file changed, 12 insertions(+), 1 deletion(-)
diff --git a/loopy/buffer.py b/loopy/buffer.py
index 46ebeae7c..a5721890e 100644
--- a/loopy/buffer.py
+++ b/loopy/buffer.py
@@ -323,6 +323,13 @@ def buffer_array(kernel, var_name, buffer_inames, init_expression=None,
aar = ArrayAccessReplacer(kernel, var_name, within, abm, buf_var)
kernel = aar.map_kernel(kernel)
+ did_write = False
+ for insn_id in aar.modified_insn_ids:
+ insn = kernel.id_to_insn[insn_id]
+ if any(assignee_name == buf_var_name
+ for assignee_name, _ in insn.assignees_and_indices()):
+ did_write = True
+
# {{{ add init_insn_id to insn_deps
new_insns = []
@@ -377,9 +384,13 @@ def buffer_array(kernel, var_name, buffer_inames, init_expression=None,
# }}}
+ new_insns.append(init_instruction)
+ if did_write:
+ new_insns.append(store_instruction)
+
kernel = kernel.copy(
domains=new_kernel_domains,
- instructions=new_insns + [init_instruction, store_instruction],
+ instructions=new_insns,
temporary_variables=new_temporary_variables)
from loopy import tag_inames
--
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