--- ./libgo/runtime/malloc.goc.ORIGIN	2017-06-09 16:45:54 +0200
+++ ./libgo/runtime/malloc.goc	2017-06-09 16:45:59 +0200
@@ -41,7 +41,14 @@
 #define HeapBaseOptions 1
 #elif defined(_AIX)
 // mmap adresses range start at 0x07000000_00000000 on AIX for 64 bits processes
-#define HeapBase(i) ((void*)(uintptr)(0x70ULL<<52))
+// Previously : #define HeapBase(i) ((void*)(uintptr)(0x70ULL<<52))
+// On AIX, the first set of address ranges available for mmap consists of the
+// range 0x07000000_00000000-0x07FFFFFF_FFFFFFFF.  It is available for both
+// fixed-location and variable-location mappings.  However, since the 64-bit
+// Go runtime does not actually reserve the arena range, we start the arena
+// range at a slightly higher location so that it is not stolen by
+// allocmcache/sysAlloc.
+#define HeapBase(i) ((void*)(uintptr)(0x70ULL<<52|1ULL<<32))
 #define HeapBaseOptions 1
 #else
 #define HeapBase(i) ((void*)(uintptr)(i<<40|0x00c0ULL<<32))