From bc390ae72ff974d6985639b5b392f6e9192c2ee7 Mon Sep 17 00:00:00 2001
From: Richard Biener <rguenther@suse.de>
Date: Tue, 14 Nov 2023 12:53:18 +0100
Subject: [PATCH] Loop distribution fix for SCC detection
The following adjusts data_dep_in_cycle_p to properly consider the
whole loop nest when looking for data dep cycles and exempting
zero-distance DDRs instead of just the outermost loop.
* tree-loop-distribution.cc (loop_distribution::data_dep_in_cycle_p):
Consider all loops in the nest when looking for
lambda_vector_zerop.
---
gcc/tree-loop-distribution.cc | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/gcc/tree-loop-distribution.cc b/gcc/tree-loop-distribution.cc
index 8e92af61c57f..5ededd97c3d6 100644
--- a/gcc/tree-loop-distribution.cc
+++ b/gcc/tree-loop-distribution.cc
@@ -1440,7 +1440,7 @@ loop_distribution::data_dep_in_cycle_p (struct graph *rdg,
else if (DDR_NUM_DIST_VECTS (ddr) > 1)
return true;
else if (DDR_REVERSED_P (ddr)
- || lambda_vector_zerop (DDR_DIST_VECT (ddr, 0), 1))
+ || lambda_vector_zerop (DDR_DIST_VECT (ddr, 0), DDR_NB_LOOPS (ddr)))
return false;
return true;
--
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