[PATCH] D50839: [llvm] Make YAML serialization up to 2.5 times faster

[Andrea Di Biagio via Phabricator via llvm-commits]

andreadb added a comment.

Hi Kirill,



================
Comment at: llvm/trunk/include/llvm/Support/YAMLTraits.h:464
 
-  static const char HexChars[] = "0123456789abcdefABCDEF";
-  if (S.startswith("0x") &&
-      S.drop_front(2).find_first_not_of(HexChars) == StringRef::npos)
+  if (S.equals(".nan") || S.equals(".NaN") || S.equals(".NAN"))
     return true;
----------------
You can probably use `StringRef::compare_lower()` rather than enumerating all the possible strings in input.


================
Comment at: llvm/trunk/include/llvm/Support/YAMLTraits.h:472
+  // expensive.
+  if (Tail.equals(".inf") || Tail.equals(".Inf") || Tail.equals(".INF"))
     return true;
----------------
Same.


================
Comment at: llvm/trunk/include/llvm/Support/YAMLTraits.h:536
+
+  assert(FoundExponent && "Should have found exponent at this point.");
+  if (S.empty())
----------------
This assert is wrong.

It should be:
```
assert(State == FoundExponent && "Should have found exponent at this point.");
```

This is causing some spurious warnings on gcc.
```
YAMLTraits.h:536: warning: enum constant in boolean context [-Wint-in-bool-context].


Repository:
  rL LLVM

https://reviews.llvm.org/D50839