diff --git a/gcc/graphite-dependences.c b/gcc/graphite-dependences.c
index aef29acfb3a..3f4e5ea8fe6 100644
--- a/gcc/graphite-dependences.c
+++ b/gcc/graphite-dependences.c
@@ -19,18 +19,11 @@ You should have received a copy of the GNU General Public License
 along with GCC; see the file COPYING3.  If not see
 <http://www.gnu.org/licenses/>.  */
 
+#define USES_ISL
+
 #include "config.h"
 
 #ifdef HAVE_isl
-/* Workaround for GMP 5.1.3 bug, see PR56019.  */
-#include <stddef.h>
-
-#include <isl/constraint.h>
-#include <isl/set.h>
-#include <isl/map.h>
-#include <isl/union_map.h>
-#include <isl/flow.h>
-#include <isl/constraint.h>
 
 #include "system.h"
 #include "coretypes.h"
@@ -44,6 +37,14 @@ along with GCC; see the file COPYING3.  If not see
 #include "tree-pass.h"
 #include "cfgloop.h"
 #include "tree-data-ref.h"
+
+#include <isl/constraint.h>
+#include <isl/set.h>
+#include <isl/map.h>
+#include <isl/union_map.h>
+#include <isl/flow.h>
+#include <isl/constraint.h>
+
 #include "graphite-poly.h"
 
 
diff --git a/gcc/graphite-isl-ast-to-gimple.c b/gcc/graphite-isl-ast-to-gimple.c
index 557c44cf10b..b13aa128a1e 100644
--- a/gcc/graphite-isl-ast-to-gimple.c
+++ b/gcc/graphite-isl-ast-to-gimple.c
@@ -18,27 +18,11 @@ You should have received a copy of the GNU General Public License
 along with GCC; see the file COPYING3.  If not see
 <http://www.gnu.org/licenses/>.  */
 
+#define USES_ISL
+
 #include "config.h"
 
 #ifdef HAVE_isl
-/* Workaround for GMP 5.1.3 bug, see PR56019.  */
-#include <stddef.h>
-
-#include <isl/constraint.h>
-#include <isl/set.h>
-#include <isl/union_set.h>
-#include <isl/map.h>
-#include <isl/union_map.h>
-#include <isl/ast_build.h>
-
-/* Since ISL-0.13, the extern is in val_gmp.h.  */
-#if !defined(HAVE_ISL_SCHED_CONSTRAINTS_COMPUTE_SCHEDULE) && defined(__cplusplus)
-extern "C" {
-#endif
-#include <isl/val_gmp.h>
-#if !defined(HAVE_ISL_SCHED_CONSTRAINTS_COMPUTE_SCHEDULE) && defined(__cplusplus)
-}
-#endif
 
 #include "system.h"
 #include "coretypes.h"
@@ -59,19 +43,36 @@ extern "C" {
 #include "tree-pass.h"
 #include "cfgloop.h"
 #include "tree-data-ref.h"
-#include "graphite-poly.h"
 #include "tree-ssa-loop-manip.h"
 #include "tree-scalar-evolution.h"
 #include "gimple-ssa.h"
 #include "tree-phinodes.h"
 #include "tree-into-ssa.h"
 #include "ssa-iterators.h"
-#include "graphite-isl-ast-to-gimple.h"
 #include "tree-cfg.h"
 #include "gimple-pretty-print.h"
 #include "cfganal.h"
 #include "value-prof.h"
 
+#include <isl/constraint.h>
+#include <isl/set.h>
+#include <isl/union_set.h>
+#include <isl/map.h>
+#include <isl/union_map.h>
+#include <isl/ast_build.h>
+
+/* Since ISL-0.13, the extern is in val_gmp.h.  */
+#if !defined(HAVE_ISL_SCHED_CONSTRAINTS_COMPUTE_SCHEDULE) && defined(__cplusplus)
+extern "C" {
+#endif
+#include <isl/val_gmp.h>
+#if !defined(HAVE_ISL_SCHED_CONSTRAINTS_COMPUTE_SCHEDULE) && defined(__cplusplus)
+}
+#endif
+
+#include "graphite-poly.h"
+#include "graphite-isl-ast-to-gimple.h"
+
 #include <map>
 
 /* We always try to use signed 128 bit types, but fall back to smaller types
diff --git a/gcc/graphite-optimize-isl.c b/gcc/graphite-optimize-isl.c
index c09264bf093..6ae224fd53a 100644
--- a/gcc/graphite-optimize-isl.c
+++ b/gcc/graphite-optimize-isl.c
@@ -18,11 +18,25 @@ You should have received a copy of the GNU General Public License
 along with GCC; see the file COPYING3.  If not see
 <http://www.gnu.org/licenses/>.  */
 
+#define USES_ISL
+
 #include "config.h"
 
 #ifdef HAVE_isl
-/* Workaround for GMP 5.1.3 bug, see PR56019.  */
-#include <stddef.h>
+
+#include "system.h"
+#include "coretypes.h"
+#include "backend.h"
+#include "cfghooks.h"
+#include "tree.h"
+#include "gimple.h"
+#include "fold-const.h"
+#include "gimple-iterator.h"
+#include "tree-ssa-loop.h"
+#include "cfgloop.h"
+#include "tree-data-ref.h"
+#include "params.h"
+#include "dumpfile.h"
 
 #include <isl/constraint.h>
 #include <isl/set.h>
@@ -38,20 +52,7 @@ along with GCC; see the file COPYING3.  If not see
 #include <isl/schedule_node.h>
 #endif
 
-#include "system.h"
-#include "coretypes.h"
-#include "backend.h"
-#include "cfghooks.h"
-#include "tree.h"
-#include "gimple.h"
-#include "fold-const.h"
-#include "gimple-iterator.h"
-#include "tree-ssa-loop.h"
-#include "cfgloop.h"
-#include "tree-data-ref.h"
 #include "graphite-poly.h"
-#include "params.h"
-#include "dumpfile.h"
 
 #ifdef HAVE_ISL_OPTIONS_SET_SCHEDULE_SERIALIZE_SCCS
 
diff --git a/gcc/graphite-poly.c b/gcc/graphite-poly.c
index 809670ab330..9137cc43b34 100644
--- a/gcc/graphite-poly.c
+++ b/gcc/graphite-poly.c
@@ -19,11 +19,25 @@ You should have received a copy of the GNU General Public License
 along with GCC; see the file COPYING3.  If not see
 <http://www.gnu.org/licenses/>.  */
 
+#define USES_ISL
+
 #include "config.h"
 
 #ifdef HAVE_isl
-/* Workaround for GMP 5.1.3 bug, see PR56019.  */
-#include <stddef.h>
+
+#include "system.h"
+#include "coretypes.h"
+#include "backend.h"
+#include "tree.h"
+#include "gimple.h"
+#include "cfghooks.h"
+#include "gimple-pretty-print.h"
+#include "diagnostic-core.h"
+#include "fold-const.h"
+#include "gimple-iterator.h"
+#include "tree-ssa-loop.h"
+#include "cfgloop.h"
+#include "tree-data-ref.h"
 
 #include <isl/constraint.h>
 #include <isl/set.h>
@@ -43,19 +57,6 @@ extern "C" {
 }
 #endif
 
-#include "system.h"
-#include "coretypes.h"
-#include "backend.h"
-#include "tree.h"
-#include "gimple.h"
-#include "cfghooks.h"
-#include "gimple-pretty-print.h"
-#include "diagnostic-core.h"
-#include "fold-const.h"
-#include "gimple-iterator.h"
-#include "tree-ssa-loop.h"
-#include "cfgloop.h"
-#include "tree-data-ref.h"
 #include "graphite-poly.h"
 
 #define OPENSCOP_MAX_STRING 256
diff --git a/gcc/graphite-scop-detection.c b/gcc/graphite-scop-detection.c
index 84fe945e74a..60bb0499f08 100644
--- a/gcc/graphite-scop-detection.c
+++ b/gcc/graphite-scop-detection.c
@@ -19,16 +19,11 @@ You should have received a copy of the GNU General Public License
 along with GCC; see the file COPYING3.  If not see
 <http://www.gnu.org/licenses/>.  */
 
+#define USES_ISL
+
 #include "config.h"
 
 #ifdef HAVE_isl
-/* Workaround for GMP 5.1.3 bug, see PR56019.  */
-#include <stddef.h>
-
-#include <isl/constraint.h>
-#include <isl/set.h>
-#include <isl/map.h>
-#include <isl/union_map.h>
 
 #include "system.h"
 #include "coretypes.h"
@@ -51,11 +46,17 @@ along with GCC; see the file COPYING3.  If not see
 #include "tree-data-ref.h"
 #include "tree-scalar-evolution.h"
 #include "tree-pass.h"
-#include "graphite-poly.h"
 #include "tree-ssa-propagate.h"
-#include "graphite-scop-detection.h"
 #include "gimple-pretty-print.h"
 
+#include <isl/constraint.h>
+#include <isl/set.h>
+#include <isl/map.h>
+#include <isl/union_map.h>
+
+#include "graphite-poly.h"
+#include "graphite-scop-detection.h"
+
 class debug_printer
 {
 private:
diff --git a/gcc/graphite-sese-to-poly.c b/gcc/graphite-sese-to-poly.c
index 83acc4ac6ca..34aa4763c41 100644
--- a/gcc/graphite-sese-to-poly.c
+++ b/gcc/graphite-sese-to-poly.c
@@ -18,28 +18,11 @@ You should have received a copy of the GNU General Public License
 along with GCC; see the file COPYING3.  If not see
 <http://www.gnu.org/licenses/>.  */
 
+#define USES_ISL
+
 #include "config.h"
 
 #ifdef HAVE_isl
-/* Workaround for GMP 5.1.3 bug, see PR56019.  */
-#include <stddef.h>
-
-#include <isl/constraint.h>
-#include <isl/set.h>
-#include <isl/map.h>
-#include <isl/union_map.h>
-#include <isl/constraint.h>
-#include <isl/aff.h>
-#include <isl/val.h>
-
-/* Since ISL-0.13, the extern is in val_gmp.h.  */
-#if !defined(HAVE_ISL_SCHED_CONSTRAINTS_COMPUTE_SCHEDULE) && defined(__cplusplus)
-extern "C" {
-#endif
-#include <isl/val_gmp.h>
-#if !defined(HAVE_ISL_SCHED_CONSTRAINTS_COMPUTE_SCHEDULE) && defined(__cplusplus)
-}
-#endif
 
 #include "system.h"
 #include "coretypes.h"
@@ -63,8 +46,26 @@ extern "C" {
 #include "tree-data-ref.h"
 #include "tree-scalar-evolution.h"
 #include "domwalk.h"
-#include "graphite-poly.h"
 #include "tree-ssa-propagate.h"
+
+#include <isl/constraint.h>
+#include <isl/set.h>
+#include <isl/map.h>
+#include <isl/union_map.h>
+#include <isl/constraint.h>
+#include <isl/aff.h>
+#include <isl/val.h>
+
+/* Since ISL-0.13, the extern is in val_gmp.h.  */
+#if !defined(HAVE_ISL_SCHED_CONSTRAINTS_COMPUTE_SCHEDULE) && defined(__cplusplus)
+extern "C" {
+#endif
+#include <isl/val_gmp.h>
+#if !defined(HAVE_ISL_SCHED_CONSTRAINTS_COMPUTE_SCHEDULE) && defined(__cplusplus)
+}
+#endif
+
+#include "graphite-poly.h"
 #include "graphite-sese-to-poly.h"
 
 /* Assigns to RES the value of the INTEGER_CST T.  */
diff --git a/gcc/graphite.c b/gcc/graphite.c
index 5316bc4fa7d..c2efdc95925 100644
--- a/gcc/graphite.c
+++ b/gcc/graphite.c
@@ -27,19 +27,9 @@ along with GCC; see the file COPYING3.  If not see
    The wiki page http://gcc.gnu.org/wiki/Graphite contains pointers to
    the related work.  */
 
+#define USES_ISL
+
 #include "config.h"
-
-#ifdef HAVE_isl
-/* Workaround for GMP 5.1.3 bug, see PR56019.  */
-#include <stddef.h>
-
-#include <isl/constraint.h>
-#include <isl/set.h>
-#include <isl/map.h>
-#include <isl/options.h>
-#include <isl/union_map.h>
-#endif
-
 #include "system.h"
 #include "coretypes.h"
 #include "backend.h"
@@ -59,10 +49,17 @@ along with GCC; see the file COPYING3.  If not see
 #include "tree-ssa-loop.h"
 #include "tree-data-ref.h"
 #include "tree-scalar-evolution.h"
-#include "graphite-poly.h"
 #include "dbgcnt.h"
 #include "tree-parloops.h"
 #include "tree-cfgcleanup.h"
+
+#include <isl/constraint.h>
+#include <isl/set.h>
+#include <isl/map.h>
+#include <isl/options.h>
+#include <isl/union_map.h>
+
+#include "graphite-poly.h"
 #include "graphite-scop-detection.h"
 #include "graphite-isl-ast-to-gimple.h"
 #include "graphite-sese-to-poly.h"
diff --git a/gcc/system.h b/gcc/system.h
index ed3de9f1c7f..498596f7fef 100644
--- a/gcc/system.h
+++ b/gcc/system.h
@@ -798,9 +798,12 @@ extern void fancy_abort (const char *, int, const char *) ATTRIBUTE_NORETURN;
    compiling gcc, so that the autoconf declaration tests for malloc
    etc don't spuriously fail.  */
 #ifdef IN_GCC
+
+#ifndef USES_ISL
 #undef calloc
 #undef strdup
  #pragma GCC poison calloc strdup
+#endif
 
 #if !defined(FLEX_SCANNER) && !defined(YYBISON)
 #undef malloc