gcc 4.9 by default does some optimizations that break perl (#121505)

Patch by Tony Cook

1 files changed, 17 insertions, 1 deletions

diff --git a/Configure b/Configure
index 15b3da1769..2d01f918e4 100755
--- a/Configure
+++ b/Configure
@@ -28,7 +28,7 @@
 # See Porting/pumpkin.pod for more information on metaconfig.
 #
 
-# Generated on Sun Mar 16 09:41:42 CET 2014 [metaconfig 3.5 PL0]
+# Generated on Wed Apr  9 10:58:09 CEST 2014 [metaconfig 3.5 PL0]
 # (with additional metaconfig patches by perlbug@perl.org)
 
 cat >c1$$ <<EOF
@@ -4643,6 +4643,22 @@ case "$gccversion" in
     $rm -f try try.*
 esac
 
+# gcc 4.9 by default does some optimizations that break perl.
+# see ticket 121505.
+#
+# The -fwrapv disables those optimizations (and probably others,) so
+# for gcc 4.9 (and later, since the optimizations probably won't go
+# away), add -fwrapv unless the user requests -fno-wrapv, which
+# disables -fwrapv, or if the user requests -fsanitize=undefined,
+# which turns the overflows -fwrapv ignores into runtime errors.
+case "$gccversion" in
+4.9.*|4.1[0-9].*|[5-9].*)
+    case "$ccflags" in
+    *-fno-wrapv*|*-fsanitize=undefined*|*-fwrapv*) ;;
+    *) ccflags="$ccflags -fwrapv" ;;
+    esac
+esac
+
 : What should the include directory be ?
 : Use sysroot if set, so findhdr looks in the right place.
 echo " "