--- MITgcm/tools/build_options/linux_amd64_open64	2011/08/17 14:53:19	1.2
+++ MITgcm/tools/build_options/linux_amd64_open64	2011/08/18 22:04:49	1.3
@@ -1,6 +1,6 @@
 #!/bin/bash
 #
-#  $Header: /home/ubuntu/mnt/e9_copy/MITgcm/tools/build_options/linux_amd64_open64,v 1.2 2011/08/17 14:53:19 jmc Exp $
+#  $Header: /home/ubuntu/mnt/e9_copy/MITgcm/tools/build_options/linux_amd64_open64,v 1.3 2011/08/18 22:04:49 jmc Exp $
 #  $Name:  $
 #
 # Build options for Open64 Compiler on Linux x86-64
@@ -38,7 +38,12 @@
 #FFLAGS="$FFLAGS -r8"
 
 if test "x$IEEE" = x ; then     #- with optimisation:
-    FOPTIM='-O3 -LNO:fusion=2 -OPT:roundoff=1:IEEE_arithmetic=3' # -funsafe-math-optimizations'
+   #- full optimisation
+   # ("-Ofast" eqv "-O3 -ipa -OPT:Ofast -fno-math-errno -ffast-math" and "-OPT:Ofast"
+   #  eqv to "-OPT:roundoff=2 -OPT:Olimit=0 -OPT:div_split=ON -OPT:alias=typed")
+    FOPTIM='-Ofast -LNO:fusion=2 -OPT:roundoff=1:IEEE_arithmetic=3'
+   #- high optimisation (-O3), might find Pb with few S/R; fully safe: switch to -O2:
+   #FOPTIM='-O3 -LNO:fusion=2 -OPT:roundoff=1:IEEE_arithmetic=3'
 else
   if test "x$DEVEL" = x ; then  #- no optimisation + IEEE :
     FOPTIM='-O0 -OPT:roundoff=0:IEEE_arithmetic=1 -fmath-errno -fno-fast-math'