diff --git a/openmp/runtime/src/z_Windows_NT-586_util.cpp b/openmp/runtime/src/z_Windows_NT-586_util.cpp
--- a/openmp/runtime/src/z_Windows_NT-586_util.cpp
+++ b/openmp/runtime/src/z_Windows_NT-586_util.cpp
@@ -149,6 +149,10 @@
 #endif
 
   switch (argc) {
+  default:
+    fprintf(stderr, "Too many args to microtask: %d!\n", argc);
+    fflush(stderr);
+    exit(-1);
   case 0:
     (*pkfn)(&gtid, &tid);
     break;
@@ -167,18 +171,50 @@
   case 5:
     (*pkfn)(&gtid, &tid, p_argv[0], p_argv[1], p_argv[2], p_argv[3], p_argv[4]);
     break;
-  default: {
-    // p_argv[6] and onwards must be passed on the stack since 8 registers are
-    // already used.
-    size_t len = (argc - 6) * sizeof(void *);
-    void *argbuf = alloca(len);
-    memcpy(argbuf, &p_argv[6], len);
-  }
-    [[fallthrough]];
   case 6:
     (*pkfn)(&gtid, &tid, p_argv[0], p_argv[1], p_argv[2], p_argv[3], p_argv[4],
             p_argv[5]);
     break;
+  case 7:
+    (*pkfn)(&gtid, &tid, p_argv[0], p_argv[1], p_argv[2], p_argv[3], p_argv[4],
+            p_argv[5], p_argv[6]);
+    break;
+  case 8:
+    (*pkfn)(&gtid, &tid, p_argv[0], p_argv[1], p_argv[2], p_argv[3], p_argv[4],
+            p_argv[5], p_argv[6], p_argv[7]);
+    break;
+  case 9:
+    (*pkfn)(&gtid, &tid, p_argv[0], p_argv[1], p_argv[2], p_argv[3], p_argv[4],
+            p_argv[5], p_argv[6], p_argv[7], p_argv[8]);
+    break;
+  case 10:
+    (*pkfn)(&gtid, &tid, p_argv[0], p_argv[1], p_argv[2], p_argv[3], p_argv[4],
+            p_argv[5], p_argv[6], p_argv[7], p_argv[8], p_argv[9]);
+    break;
+  case 11:
+    (*pkfn)(&gtid, &tid, p_argv[0], p_argv[1], p_argv[2], p_argv[3], p_argv[4],
+            p_argv[5], p_argv[6], p_argv[7], p_argv[8], p_argv[9], p_argv[10]);
+    break;
+  case 12:
+    (*pkfn)(&gtid, &tid, p_argv[0], p_argv[1], p_argv[2], p_argv[3], p_argv[4],
+            p_argv[5], p_argv[6], p_argv[7], p_argv[8], p_argv[9], p_argv[10],
+            p_argv[11]);
+    break;
+  case 13:
+    (*pkfn)(&gtid, &tid, p_argv[0], p_argv[1], p_argv[2], p_argv[3], p_argv[4],
+            p_argv[5], p_argv[6], p_argv[7], p_argv[8], p_argv[9], p_argv[10],
+            p_argv[11], p_argv[12]);
+    break;
+  case 14:
+    (*pkfn)(&gtid, &tid, p_argv[0], p_argv[1], p_argv[2], p_argv[3], p_argv[4],
+            p_argv[5], p_argv[6], p_argv[7], p_argv[8], p_argv[9], p_argv[10],
+            p_argv[11], p_argv[12], p_argv[13]);
+    break;
+  case 15:
+    (*pkfn)(&gtid, &tid, p_argv[0], p_argv[1], p_argv[2], p_argv[3], p_argv[4],
+            p_argv[5], p_argv[6], p_argv[7], p_argv[8], p_argv[9], p_argv[10],
+            p_argv[11], p_argv[12], p_argv[13], p_argv[14]);
+    break;
   }
 
 #if OMPT_SUPPORT