[ADT] Add llvm::to_float

Summary:
The function matches the interface of llvm::to_integer, but as we are
calling out to a C library function, I let it take a Twine argument, so
we can avoid a string copy at least in some cases.

I add a test and replace a couple of existing uses of strtod with this
function.

Reviewers: zturner

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D34518

llvm-svn: 306096

1 files changed, 7 insertions, 12 deletions

diff --git a/llvm/lib/Support/YAMLTraits.cpp b/llvm/lib/Support/YAMLTraits.cpp
index 8684cd950d8..601084f9eae 100644
--- a/llvm/lib/Support/YAMLTraits.cpp
+++ b/llvm/lib/Support/YAMLTraits.cpp
@@ -10,6 +10,7 @@
 #include "llvm/Support/YAMLTraits.h"
 #include "llvm/ADT/STLExtras.h"
 #include "llvm/ADT/SmallString.h"
+#include "llvm/ADT/StringExtras.h"
 #include "llvm/ADT/StringRef.h"
 #include "llvm/ADT/Twine.h"
 #include "llvm/Support/Casting.h"
@@ -912,12 +913,9 @@ void ScalarTraits<double>::output(const double &Val, void *, raw_ostream &Out) {
 }
 
 StringRef ScalarTraits<double>::input(StringRef Scalar, void *, double &Val) {
-  SmallString<32> buff(Scalar.begin(), Scalar.end());
-  char *end;
-  Val = strtod(buff.c_str(), &end);
-  if (*end != '\0')
-    return "invalid floating point number";
-  return StringRef();
+  if (to_float(Scalar, Val))
+    return StringRef();
+  return "invalid floating point number";
 }
 
 void ScalarTraits<float>::output(const float &Val, void *, raw_ostream &Out) {
@@ -925,12 +923,9 @@ void ScalarTraits<float>::output(const float &Val, void *, raw_ostream &Out) {
 }
 
 StringRef ScalarTraits<float>::input(StringRef Scalar, void *, float &Val) {
-  SmallString<32> buff(Scalar.begin(), Scalar.end());
-  char *end;
-  Val = strtod(buff.c_str(), &end);
-  if (*end != '\0')
-    return "invalid floating point number";
-  return StringRef();
+  if (to_float(Scalar, Val))
+    return StringRef();
+  return "invalid floating point number";
 }
 
 void ScalarTraits<Hex8>::output(const Hex8 &Val, void *, raw_ostream &Out) {