diff --git a/compiler-rt/lib/builtins/floatsisf.c b/compiler-rt/lib/builtins/floatsisf.c
--- a/compiler-rt/lib/builtins/floatsisf.c
+++ b/compiler-rt/lib/builtins/floatsisf.c
@@ -33,7 +33,7 @@
   }
 
   // Exponent of (fp_t)a is the width of abs(a).
-  const int exponent = (aWidth - 1) - __builtin_clz(a);
+  const int exponent = (aWidth - 1) - clzsi(a);
   rep_t result;
 
   // Shift a into the significand field, rounding if it is a right-shift
diff --git a/compiler-rt/lib/builtins/floatsitf.c b/compiler-rt/lib/builtins/floatsitf.c
--- a/compiler-rt/lib/builtins/floatsitf.c
+++ b/compiler-rt/lib/builtins/floatsitf.c
@@ -33,7 +33,7 @@
   }
 
   // Exponent of (fp_t)a is the width of abs(a).
-  const int exponent = (aWidth - 1) - __builtin_clz(aAbs);
+  const int exponent = (aWidth - 1) - clzsi(aAbs);
   rep_t result;
 
   // Shift a into the significand field and clear the implicit bit.
diff --git a/compiler-rt/lib/builtins/floatunsisf.c b/compiler-rt/lib/builtins/floatunsisf.c
--- a/compiler-rt/lib/builtins/floatunsisf.c
+++ b/compiler-rt/lib/builtins/floatunsisf.c
@@ -26,7 +26,7 @@
     return fromRep(0);
 
   // Exponent of (fp_t)a is the width of abs(a).
-  const int exponent = (aWidth - 1) - __builtin_clz(a);
+  const int exponent = (aWidth - 1) - clzsi(a);
   rep_t result;
 
   // Shift a into the significand field, rounding if it is a right-shift
diff --git a/compiler-rt/lib/builtins/floatunsitf.c b/compiler-rt/lib/builtins/floatunsitf.c
--- a/compiler-rt/lib/builtins/floatunsitf.c
+++ b/compiler-rt/lib/builtins/floatunsitf.c
@@ -25,7 +25,7 @@
     return fromRep(0);
 
   // Exponent of (fp_t)a is the width of abs(a).
-  const int exponent = (aWidth - 1) - __builtin_clz(a);
+  const int exponent = (aWidth - 1) - clzsi(a);
   rep_t result;
 
   // Shift a into the significand field and clear the implicit bit.
diff --git a/compiler-rt/lib/builtins/fp_extend.h b/compiler-rt/lib/builtins/fp_extend.h
--- a/compiler-rt/lib/builtins/fp_extend.h
+++ b/compiler-rt/lib/builtins/fp_extend.h
@@ -33,9 +33,9 @@
   return __builtin_clzl(a);
 #else
   if (a & REP_C(0xffffffff00000000))
-    return __builtin_clz(a >> 32);
+    return clzsi(a >> 32);
   else
-    return 32 + __builtin_clz(a & REP_C(0xffffffff));
+    return 32 + clzsi(a & REP_C(0xffffffff));
 #endif
 }
 
diff --git a/compiler-rt/lib/builtins/udivmoddi4.c b/compiler-rt/lib/builtins/udivmoddi4.c
--- a/compiler-rt/lib/builtins/udivmoddi4.c
+++ b/compiler-rt/lib/builtins/udivmoddi4.c
@@ -82,7 +82,7 @@
         r.s.high = n.s.high & (d.s.high - 1);
         *rem = r.all;
       }
-      return n.s.high >> __builtin_ctz(d.s.high);
+      return n.s.high >> ctzsi(d.s.high);
     }
     // K K
     // ---
@@ -112,7 +112,7 @@
           *rem = n.s.low & (d.s.low - 1);
         if (d.s.low == 1)
           return n.all;
-        sr = __builtin_ctz(d.s.low);
+        sr = ctzsi(d.s.low);
         q.s.high = n.s.high >> sr;
         q.s.low = (n.s.high << (n_uword_bits - sr)) | (n.s.low >> sr);
         return q.all;