Hex literals without a significand no longer crash the lexer.  Fixes bug 7910

Patch by Eitan Adler

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@149984 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/test/Lexer/hexfloat.cpp b/test/Lexer/hexfloat.cpp
index 23daa49..ad4e50a 100644
--- a/test/Lexer/hexfloat.cpp
+++ b/test/Lexer/hexfloat.cpp
@@ -1,4 +1,5 @@
 // RUN: %clang_cc1 -fsyntax-only -verify -pedantic %s
 // RUN: %clang_cc1 -std=c++11 -fsyntax-only -verify -pedantic %s
 float f = 0x1p+1; // expected-warning{{hexadecimal floating constants are a C99 feature}}
+double e = 0x.p0; //expected-error{{hexadecimal floating constants require a significand}}