I've narrowed this down to the optimization for tree-vrp.
Here is a patch which may be of interest ...
--- old/debian/rules 2014-09-09 13:55:04.000000000 -0600
+++ new/debian/rules 2015-05-08 09:00:40.307975277 -0600
@@ -6,8 +6,11 @@
DEB_HOST_GNU_TYPE ?= $(shell dpkg-architecture -qDEB_HOST_GNU_TYPE)
DEB_BUILD_GNU_TYPE ?= $(shell dpkg-architecture -qDEB_BUILD_GNU_TYPE)
-CFLAGS = -Wall -g
-CFLAGS += -O2
+export DEB_BUILD_MAINT_OPTIONS = hardening=+all
+DPKG_EXPORT_BUILDFLAGS = 1
+
+CFLAGS += -Wall -fno-tree-vrp
version=`ls src/.libs/lib*.so.* | \
awk '{if (match($$0,/[0-9]+\.[0-9]+\.[0-9]+$$/)) print substr($$0,RSTART)}'`