diff --git a/compiler-rt/lib/builtins/udivdi3.c b/compiler-rt/lib/builtins/udivdi3.c
--- a/compiler-rt/lib/builtins/udivdi3.c
+++ b/compiler-rt/lib/builtins/udivdi3.c
@@ -15,5 +15,15 @@
 // Returns: a / b
 
 COMPILER_RT_ABI du_int __udivdi3(du_int a, du_int b) {
-  return __udivmoddi4(a, b, 0);
+  const int N = sizeof(du_int) * CHAR_BIT;
+  du_int r = 0;
+  for (int i = 0; i < N; i++) {
+    r = (r << 1) | (a >> (N-1));
+    a <<= 1;
+    if (r >= b) {
+      r -= b;
+      ++a;
+    }
+  }
+  return a;
 }
diff --git a/compiler-rt/lib/builtins/umoddi3.c b/compiler-rt/lib/builtins/umoddi3.c
--- a/compiler-rt/lib/builtins/umoddi3.c
+++ b/compiler-rt/lib/builtins/umoddi3.c
@@ -15,7 +15,15 @@
 // Returns: a % b
 
 COMPILER_RT_ABI du_int __umoddi3(du_int a, du_int b) {
-  du_int r;
-  __udivmoddi4(a, b, &r);
+  const int N = sizeof(du_int) * CHAR_BIT;
+  du_int r = 0;
+  for (int i = 0; i < N; i++) {
+    r = (r << 1) | (a >> (N-1));
+    a <<= 1;
+    if (r >= b) {
+      r -= b;
+      ++a;
+    }
+  }
   return r;
 }