alpha.core.UnreachableCode - don't warn about unreachable code inside macro

In macros, 'do {...} while (0)' is often used. Don't warn about the condition 0 when it is unreachable.

Differential Revision: https://reviews.llvm.org/D25606

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@284477 91177308-0d34-0410-b5e6-96231b3b80d8
(cherry picked from commit a56684f9d508e1d4c80eb238f712762f23247a27)
2 files changed