https://bugs.gentoo.org/703538

--- a/js/src/jit/ProcessExecutableMemory.cpp
+++ b/js/src/jit/ProcessExecutableMemory.cpp
@@ -248,7 +248,11 @@ static void* ComputeRandomAllocationAddress() {
   // x64 CPUs have a 48-bit address space and on some platforms the OS will
   // give us access to 47 bits, so to be safe we right shift by 18 to leave
   // 46 bits.
+#ifdef __ia64__
+  rand >>= 20; // upper 20 mits are reserved for virtual memory type tag
+#else
   rand >>= 18;
+#endif
 #else
   // On 32-bit, right shift by 34 to leave 30 bits, range [0, 1GiB). Then add
   // 512MiB to get range [512MiB, 1.5GiB), or [0x20000000, 0x60000000). This