[libcxx] use __builtin_isnan in std::isnan.

TocarIP · TocarIP · commit 767eadd78229 · 2019-11-15T12:29:18.000-05:00
Summary: This allows std::isnan to be fully inlined, instead of generating calls. Reviewers: EricWF Reviewed By: EricWF Subscribers: christof, ldionne Differential Revision: https://reviews.llvm.org/D69806
diff --git a/libcxx/include/math.h b/libcxx/include/math.h
@@ -510,7 +510,11 @@ _LIBCPP_INLINE_VISIBILITY
 bool
 __libcpp_isnan(_A1 __lcpp_x) _NOEXCEPT
 {
+#if __has_builtin(__builtin_isnan)
+    return __builtin_isnan(__lcpp_x);
+#else
     return isnan(__lcpp_x);
+#endif
 }
 
 #undef isnan

Original file line number	Diff line number	Diff line change
`@@ -510,7 +510,11 @@ _LIBCPP_INLINE_VISIBILITY`
`510`	`510`	`bool`
`511`	`511`	`__libcpp_isnan(_A1 __lcpp_x) _NOEXCEPT`
`512`	`512`	`{`
	`513`	`+#if __has_builtin(__builtin_isnan)`
	`514`	`+ return __builtin_isnan(__lcpp_x);`
	`515`	`+#else`
`513`	`516`	`return isnan(__lcpp_x);`
	`517`	`+#endif`
`514`	`518`	`}`
`515`	`519`
`516`	`520`	`#undef isnan`