From 3037494556b0d56b91590d4a3b502e208df249e0 Mon Sep 17 00:00:00 2001
From: Sam Yates <yates@cscs.ch>
Date: Wed, 22 Aug 2018 16:58:19 +0200
Subject: [PATCH] Refine gcc version test for FMA work-around. (#573)
Fixes #568.
---
include/arbor/util/compat.hpp | 10 ++++++++--
1 file changed, 8 insertions(+), 2 deletions(-)
diff --git a/include/arbor/util/compat.hpp b/include/arbor/util/compat.hpp
index 5ddf7e38..46eacb06 100644
--- a/include/arbor/util/compat.hpp
+++ b/include/arbor/util/compat.hpp
@@ -37,10 +37,16 @@ inline void compiler_barrier_if_icc_leq(unsigned ver) {
#endif
}
-// Work-around for bad vectorization of fma in gcc version < 8.2
+// Work-around for bad vectorization of fma in gcc.
+// Bug fixed in 6.4.1, 7.3.1, 8.1.1 and 9.0: refer to gcc bug #85597,
+// https://gcc.gnu.org/bugzilla/show_bug.cgi?id=85597
template <typename T>
-#if defined(__GNUC__) && (100*__GNUC__ + __GNUC_MINOR__ < 802)
+#if defined(__GNUC__) &&\
+ ( __GNUC__<6 ||\
+ (__GNUC__==6 && __GNUC_MINOR__*100 + __GNUC_PATCHLEVEL__ < 401) ||\
+ (__GNUC__==7 && __GNUC_MINOR__*100 + __GNUC_PATCHLEVEL__ < 301) ||\
+ (__GNUC__==8 && __GNUC_MINOR__*100 + __GNUC_PATCHLEVEL__ < 101))
__attribute((optimize("no-tree-vectorize")))
#endif
inline auto fma(T a, T b, T c) {
--
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