The return type of __builtin_clz() et al is "int", as documented and for GCC compatibility, and not "unsigned int", as previously implemented.

Author: xavierleroy

Changelog

@@ -45,6 +45,8 @@ Miscellaneous:
   passing a struct/union as function argument is now rejected.
 - The -fstruct-return command-line option is deprecated and
   becomes a synonymous for -fstruct-passing.
+- The return type of __builtin_clz() is "int", as documented,
+  and not "unsigned int", as previously implemented.
 
 
 Release 2.5, 2015-06-12

arm/CBuiltins.ml

@@ -30,7 +30,7 @@ let builtins = {
     "__builtin_bswap16",
       (TInt(IUShort, []), [TInt(IUShort, [])], false);
     "__builtin_clz",
-      (TInt(IUInt, []), [TInt(IUInt, [])], false);
+      (TInt(IInt, []), [TInt(IUInt, [])], false);
     (* Float arithmetic *)
     "__builtin_fsqrt",
       (TFloat(FDouble, []), [TFloat(FDouble, [])], false);

ia32/CBuiltins.ml

@@ -30,9 +30,9 @@ let builtins = {
     "__builtin_bswap16",
       (TInt(IUShort, []), [TInt(IUShort, [])], false);
     "__builtin_clz",
-      (TInt(IUInt, []), [TInt(IUInt, [])], false);
+      (TInt(IInt, []), [TInt(IUInt, [])], false);
     "__builtin_ctz",
-      (TInt(IUInt, []), [TInt(IUInt, [])], false);
+      (TInt(IInt, []), [TInt(IUInt, [])], false);
     (* Float arithmetic *)
     "__builtin_fsqrt",
       (TFloat(FDouble, []), [TFloat(FDouble, [])], false);

powerpc/CBuiltins.ml

@@ -29,11 +29,11 @@ let builtins = {
     "__builtin_mulhwu",
       (TInt(IUInt, []), [TInt(IUInt, []); TInt(IUInt, [])], false);
     "__builtin_clz",
-      (TInt(IUInt, []), [TInt(IUInt, [])], false);
+      (TInt(IInt, []), [TInt(IUInt, [])], false);
     "__builtin_clzl",
-      (TInt(IUInt, []), [TInt(IULong, [])], false);
+      (TInt(IInt, []), [TInt(IULong, [])], false);
     "__builtin_clzll",
-      (TInt(IUInt, []), [TInt(IULongLong, [])], false);
+      (TInt(IInt, []), [TInt(IULongLong, [])], false);
     "__builtin_bswap",
       (TInt(IUInt, []), [TInt(IUInt, [])], false);
     "__builtin_bswap32",