Index: gcc/gcc/config/i386/i386.md
===================================================================
--- gcc.orig/gcc/config/i386/i386.md
+++ gcc/gcc/config/i386/i386.md
@@ -19707,7 +19707,7 @@
    (set_attr "length" "5")])
 
 (define_insn "allocate_stack_worker_64"
-  [(set (match_operand:DI 0 "register_operand" "=a")
+  [(set (match_operand:DI 0 "register_operand" "+a")
 	(unspec_volatile:DI [(match_dup 0)] UNSPECV_STACK_PROBE))
    (set (reg:DI SP_REG) (minus:DI (reg:DI SP_REG) (match_dup 0)))
    (clobber (reg:DI R10_REG))
Index: gcc/gcc/testsuite/gcc.c-torture/execute/pr36321.c
===================================================================
--- /dev/null
+++ gcc/gcc/testsuite/gcc.c-torture/execute/pr36321.c
@@ -0,0 +1,24 @@
+extern void abort (void);
+
+extern __SIZE_TYPE__ strlen (const char *);
+void foo(char *str)
+{
+  int len2 = strlen (str);
+  char *a = (char *) __builtin_alloca (0);
+  char *b = (char *) __builtin_alloca (len2*3);
+
+  if ((int) (a-b) < (len2*3))
+    {
+#ifdef _WIN32
+      abort ();
+#endif
+      return;
+    }
+}
+
+int main(int argc, char **argv)
+{
+  foo (argv[0]);
+  return 0;
+}
+
=