Handle '.' correctly in hex float literal parsing.

There were a couple of different loops that were not handling
'.' correctly in APFloat::convertFromHexadecimalString; these mistakes
could lead to assertion failures and incorrect rounding for overlong
hex float literals.

Fixes PR16643.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@186539 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/unittests/ADT/APFloatTest.cpp b/unittests/ADT/APFloatTest.cpp
index 46dfbd1..1d6d8ca 100644
--- a/unittests/ADT/APFloatTest.cpp
+++ b/unittests/ADT/APFloatTest.cpp
@@ -766,6 +766,8 @@
   EXPECT_TRUE(APFloat(APFloat::IEEEdouble, "-99e99999").isInfinity());
   EXPECT_TRUE(APFloat(APFloat::IEEEdouble, "1e-99999").isPosZero());
   EXPECT_TRUE(APFloat(APFloat::IEEEdouble, "-1e-99999").isNegZero());
+
+  EXPECT_EQ(2.71828, convertToDoubleFromString("2.71828"));
 }
 
 TEST(APFloatTest, fromHexadecimalString) {
@@ -849,7 +851,10 @@
   EXPECT_EQ(1.0625, APFloat(APFloat::IEEEdouble, "0x1.1p0").convertToDouble());
   EXPECT_EQ(1.0, APFloat(APFloat::IEEEdouble, "0x1p0").convertToDouble());
 
-  EXPECT_EQ(2.71828, convertToDoubleFromString("2.71828"));
+  EXPECT_EQ(convertToDoubleFromString("0x1p-150"),
+            convertToDoubleFromString("+0x800000000000000001.p-221"));
+  EXPECT_EQ(2251799813685248.5,
+            convertToDoubleFromString("0x80000000000004000000.010p-28"));
 }
 
 TEST(APFloatTest, toString) {