Convert assert(0) to llvm_unreachable

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@149967 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/TableGen/TGParser.cpp b/lib/TableGen/TGParser.cpp
index 0f64f4b..c7cf097 100644
--- a/lib/TableGen/TGParser.cpp
+++ b/lib/TableGen/TGParser.cpp
@@ -729,7 +729,7 @@
     RecTy *Type = 0;
 
     switch (Lex.getCode()) {
-    default: assert(0 && "Unhandled code!");
+    default: llvm_unreachable("Unhandled code!");
     case tgtok::XCast:
       Lex.Lex();  // eat the operation
       Code = UnOpInit::CAST;
@@ -845,7 +845,7 @@
     RecTy *Type = 0;
 
     switch (OpTok) {
-    default: assert(0 && "Unhandled code!");
+    default: llvm_unreachable("Unhandled code!");
     case tgtok::XConcat: Code = BinOpInit::CONCAT;Type = DagRecTy::get(); break;
     case tgtok::XSRA:    Code = BinOpInit::SRA;   Type = IntRecTy::get(); break;
     case tgtok::XSRL:    Code = BinOpInit::SRL;   Type = IntRecTy::get(); break;
@@ -909,7 +909,7 @@
     tgtok::TokKind LexCode = Lex.getCode();
     Lex.Lex();  // eat the operation
     switch (LexCode) {
-    default: assert(0 && "Unhandled code!");
+    default: llvm_unreachable("Unhandled code!");
     case tgtok::XIf:
       Code = TernOpInit::IF;
       break;
@@ -954,7 +954,7 @@
     Lex.Lex();  // eat the ')'
 
     switch (LexCode) {
-    default: assert(0 && "Unhandled code!");
+    default: llvm_unreachable("Unhandled code!");
     case tgtok::XIf: {
       // FIXME: The `!if' operator doesn't handle non-TypedInit well at
       // all. This can be made much more robust.