[cig-commits] [commit] devel: added a comment about -qstrict (4f3d4b0)

[cig_noreply at geodynamics.org]

Repository : https://github.com/geodynamics/specfem3d_globe

On branch  : devel
Link       : https://github.com/geodynamics/specfem3d_globe/compare/9a5181b4e7b22ec3bc12c57f67ca22999e5246b2...4f3d4b0c30908471d57c87843ce56bed28e0bf21

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commit 4f3d4b0c30908471d57c87843ce56bed28e0bf21
Author: Dimitri Komatitsch <komatitsch at lma.cnrs-mrs.fr>
Date:   Mon Nov 17 10:45:25 2014 +0100

    added a comment about -qstrict


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4f3d4b0c30908471d57c87843ce56bed28e0bf21
 flags.guess | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/flags.guess b/flags.guess
index b35524d..c35fdb5 100644
--- a/flags.guess
+++ b/flags.guess
@@ -192,6 +192,10 @@ case $my_FC in
         # one should also use additional flags:
         # CFLAGS = -Wl,-relax
         #
+        # The -qstrict option prevents some minor differences of results between xlf and
+        # other compilers. There is a small decrease in performance, but generally
+        # it is small or negligible compared to other issues like slow I/O.
+        #
         # On IBM BlueGene at IDRIS (France) use:
         # -qtune=auto -qarch=450d -qsave     instead of -qtune=auto -qarch=auto
         DEF_FFLAGS="-qassert=contig -qhot -q64 -qtune=auto -qarch=auto -qcache=auto -qfree=f90 -qsuffix=f=f90 -qhalt=w -qlanglvl=2003std -g -qsuppress=1518-234 -qsuppress=1518-317 -qsuppress=1518-318 -qsuppress=1500-036"