Convert assert(0) to llvm_unreachable in X86 Target directory.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@149809 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/X86/X86ELFWriterInfo.cpp b/lib/Target/X86/X86ELFWriterInfo.cpp
index 547d683..c1a49a7 100644
--- a/lib/Target/X86/X86ELFWriterInfo.cpp
+++ b/lib/Target/X86/X86ELFWriterInfo.cpp
@@ -142,8 +142,6 @@
 
   if (RelTy == ELF::R_X86_64_PC32 || RelTy == ELF::R_386_PC32)
     return SymOffset - (RelOffset + 4);
-  else
-    assert(0 && "computeRelocation unknown for this relocation type");
 
-  return 0;
+  llvm_unreachable("computeRelocation unknown for this relocation type");
 }