5 files changed, 41 insertions, 2 deletions
diff --git a/utils/TableGen/Record.cpp b/utils/TableGen/Record.cpp
index ae2c2f3..fc2de1c 100644
--- a/utils/TableGen/Record.cpp
+++ b/utils/TableGen/Record.cpp
@@ -912,6 +912,19 @@ Init *TernOpInit::Fold(Record *CurRec, MultiClass *CurMultiClass) {
     }
     break;
   }
+
+  case IF: {
+    IntInit *LHSi = dynamic_cast<IntInit*>(LHS);
+    if (LHSi) {
+      if (LHSi->getValue()) {
+        return MHS;
+      }
+      else {
+        return RHS;
+      }
+    }
+    break;
+  }
   }
 
   return this;
@@ -932,6 +945,7 @@ std::string TernOpInit::getAsString() const {
   switch (Opc) {
   case SUBST: Result = "!subst"; break;
   case FOREACH: Result = "!foreach"; break; 
+  case IF: Result = "!if"; break; 
  }
   return Result + "(" + LHS->getAsString() + ", " + MHS->getAsString() + ", " 
     + RHS->getAsString() + ")";
diff --git a/utils/TableGen/Record.h b/utils/TableGen/Record.h
index c2549da..2153a54 100644
--- a/utils/TableGen/Record.h
+++ b/utils/TableGen/Record.h
@@ -843,7 +843,7 @@ public:
 ///
 class TernOpInit : public OpInit {
 public:
-  enum TernaryOp { SUBST, FOREACH };
+  enum TernaryOp { SUBST, FOREACH, IF };
 private:
   TernaryOp Opc;
   Init *LHS, *MHS, *RHS;
diff --git a/utils/TableGen/TGLexer.cpp b/utils/TableGen/TGLexer.cpp
index faf1e75..758d499 100644
--- a/utils/TableGen/TGLexer.cpp
+++ b/utils/TableGen/TGLexer.cpp
@@ -453,6 +453,7 @@ tgtok::TokKind TGLexer::LexExclaim() {
   if (Len == 3 && !memcmp(Start, "car", 3)) return tgtok::XCar;
   if (Len == 3 && !memcmp(Start, "cdr", 3)) return tgtok::XCdr;
   if (Len == 4 && !memcmp(Start, "null", 4)) return tgtok::XNull;
+  if (Len == 2 && !memcmp(Start, "if", 2)) return tgtok::XIf;
 
   return ReturnError(Start-1, "Unknown operator");
 }
diff --git a/utils/TableGen/TGLexer.h b/utils/TableGen/TGLexer.h
index 3d27e5e..ac3b984 100644
--- a/utils/TableGen/TGLexer.h
+++ b/utils/TableGen/TGLexer.h
@@ -46,7 +46,7 @@ namespace tgtok {
     
     // !keywords.
     XConcat, XSRA, XSRL, XSHL, XStrConcat, XNameConcat, XCast, XSubst,
-    XForEach, XCar, XCdr, XNull,
+    XForEach, XCar, XCdr, XNull, XIf,
 
     // Integer value.
     IntVal,
diff --git a/utils/TableGen/TGParser.cpp b/utils/TableGen/TGParser.cpp
index 8ff25a6..fc6f29f 100644
--- a/utils/TableGen/TGParser.cpp
+++ b/utils/TableGen/TGParser.cpp
@@ -862,6 +862,7 @@ Init *TGParser::ParseOperation(Record *CurRec) {
     return (new BinOpInit(Code, LHS, RHS, Type))->Fold(CurRec, CurMultiClass);
   }
 
+  case tgtok::XIf:
   case tgtok::XForEach:
   case tgtok::XSubst: {  // Value ::= !ternop '(' Value ',' Value ',' Value ')'
     TernOpInit::TernaryOp Code;
@@ -872,6 +873,9 @@ Init *TGParser::ParseOperation(Record *CurRec) {
     Lex.Lex();  // eat the operation
     switch (LexCode) {
     default: assert(0 && "Unhandled code!");
+    case tgtok::XIf:
+      Code = TernOpInit::IF;
+      break;
     case tgtok::XForEach:
       Code = TernOpInit::FOREACH;
       break;
@@ -914,6 +918,25 @@ Init *TGParser::ParseOperation(Record *CurRec) {
 
     switch (LexCode) {
     default: assert(0 && "Unhandled code!");
+    case tgtok::XIf: {
+      TypedInit *MHSt = dynamic_cast<TypedInit *>(MHS);
+      TypedInit *RHSt = dynamic_cast<TypedInit *>(RHS);
+      if (MHSt == 0 || RHSt == 0) {
+        TokError("could not get type for !if");
+        return 0;
+      }
+      if (MHSt->getType()->typeIsConvertibleTo(RHSt->getType())) {
+        Type = RHSt->getType();
+      }
+      else if (RHSt->getType()->typeIsConvertibleTo(MHSt->getType())) {
+        Type = MHSt->getType();
+      }
+      else {
+        TokError("inconsistent types for !if");
+        return 0;
+      }
+      break;
+    }
     case tgtok::XForEach: {
       TypedInit *MHSt = dynamic_cast<TypedInit *>(MHS);
       if (MHSt == 0) {
@@ -1152,6 +1175,7 @@ Init *TGParser::ParseSimpleValue(Record *CurRec) {
   case tgtok::XSHL:
   case tgtok::XStrConcat:
   case tgtok::XNameConcat:  // Value ::= !binop '(' Value ',' Value ')'
+  case tgtok::XIf:
   case tgtok::XForEach:
   case tgtok::XSubst: {  // Value ::= !ternop '(' Value ',' Value ',' Value ')'
     return ParseOperation(CurRec);