[PATCH] D12355: [libcxx] Optimize away unneeded length calculation in basic_string::compare(const char*)

[Marshall Clow via cfe-commits]

mclow.lists added inline comments.

================
Comment at: include/string:3801
@@ -3799,1 +3800,3 @@
+    if (__lhs_len != __rhs.size()) return false;
+    return _Traits::compare(__rhs.data(), __lhs, _VSTD::min(__lhs_len, __rhs.size())) == 0;
 }
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If the lengths are the same (and they are), you don't need the `min` of them

================
Comment at: include/string:3802
@@ -3799,2 +3801,3 @@
+    return _Traits::compare(__rhs.data(), __lhs, _VSTD::min(__lhs_len, __rhs.size())) == 0;
 }
 
----------------
Also, you should not call `traits::compare` here. You should call `__rhs.compare(0, npos, __lhs, __lhs_len)`

which is what `__rhs.compare(__lhs)` does.



http://reviews.llvm.org/D12355