Support REG_SEQUENCE in tablegen.

The problem is mostly that variadic output instruction
aren't handled, so it is rejected for having an inconsistent
number of operands, and then the right number of operands
isn't emitted.

llvm-svn: 221117

include/llvm/Target/Target.td

@@ -805,7 +805,7 @@ def DBG_VALUE : Instruction {
 }
 def REG_SEQUENCE : Instruction {
   let OutOperandList = (outs unknown:$dst);
-  let InOperandList = (ins variable_ops);
+  let InOperandList = (ins unknown:$supersrc, variable_ops);
   let AsmString = "";
   let neverHasSideEffects = 1;
   let isAsCheapAsAMove = 1;

lib/Target/R600/SIInstructions.td

@@ -1957,9 +1957,9 @@ def : Pat <
 
 def : Pat <
   (i64 (ctpop i64:$src)),
-  (INSERT_SUBREG (INSERT_SUBREG (i64 (IMPLICIT_DEF)),
+    (i64 (REG_SEQUENCE SReg_64,
-    (S_BCNT1_I32_B64 $src), sub0),
+     (S_BCNT1_I32_B64 $src), sub0,
-    (S_MOV_B32 0), sub1)
+     (S_MOV_B32 0), sub1))
 >;
 
 //===----------------------------------------------------------------------===//

utils/TableGen/CodeGenDAGPatterns.cpp

@@ -1387,7 +1387,7 @@ static EEVT::TypeSet getImplicitType(Record *R, unsigned ResNo,
 
   if (R->isSubClassOf("SubRegIndex")) {
     assert(ResNo == 0 && "SubRegisterIndices only produce one result!");
-    return EEVT::TypeSet();
+    return EEVT::TypeSet(MVT::i32, TP);
   }
 
   if (R->isSubClassOf("ValueType")) {
@@ -1529,7 +1529,16 @@ TreePatternNode::isCommutativeIntrinsic(const CodeGenDAGPatterns &CDP) const {
   return false;
 }
 
+static bool isOperandClass(const TreePatternNode *N, StringRef Class) {
+  if (!N->isLeaf())
+    return N->getOperator()->isSubClassOf(Class);
 
+  DefInit *DI = dyn_cast<DefInit>(N->getLeafValue());
+  if (DI && DI->getDef()->isSubClassOf(Class))
+    return true;
+
+  return false;
+}
 /// ApplyTypeConstraints - Apply all of the type constraints relevant to
 /// this node and its children in the tree.  This returns true if it makes a
 /// change, false otherwise.  If a type contradiction is found, flag an error.
@@ -1689,6 +1698,34 @@ bool TreePatternNode::ApplyTypeConstraints(TreePattern &TP, bool NotRegisters) {
       assert(getChild(0)->getNumTypes() == 1 && "FIXME: Unhandled");
       MadeChange |= UpdateNodeType(0, getChild(0)->getExtType(0), TP);
       MadeChange |= getChild(0)->UpdateNodeType(0, getExtType(0), TP);
+    } else if (getOperator()->getName() == "REG_SEQUENCE") {
+      // We need to do extra, custom typechecking for REG_SEQUENCE since it is
+      // variadic.
+
+      unsigned NChild = getNumChildren();
+      if (NChild < 3) {
+        TP.error("REG_SEQUENCE requires at least 3 operands!");
+        return false;
+      }
+
+      if (NChild % 2 == 0) {
+        TP.error("REG_SEQUENCE requires an odd number of operands!");
+        return false;
+      }
+
+      if (!isOperandClass(getChild(0), "RegisterClass")) {
+        TP.error("REG_SEQUENCE requires a RegisterClass for first operand!");
+        return false;
+      }
+
+      for (unsigned I = 1; I < NChild; I += 2) {
+        TreePatternNode *SubIdxChild = getChild(I + 1);
+        if (!isOperandClass(SubIdxChild, "SubRegIndex")) {
+          TP.error("REG_SEQUENCE requires a SubRegIndex for operand " +
+                   itostr(I + 1) + "!");
+          return false;
+        }
+      }
     }
 
     unsigned ChildNo = 0;
@@ -1749,7 +1786,7 @@ bool TreePatternNode::ApplyTypeConstraints(TreePattern &TP, bool NotRegisters) {
       MadeChange |= Child->UpdateNodeTypeFromInst(ChildResNo, OperandNode, TP);
     }
 
-    if (ChildNo != getNumChildren()) {
+    if (!InstInfo.Operands.isVariadic && ChildNo != getNumChildren()) {
       TP.error("Instruction '" + getOperator()->getName() +
                "' was provided too many operands!");
       return false;

utils/TableGen/DAGISelMatcherGen.cpp

@@ -755,16 +755,21 @@ EmitResultInstructionAsOperand(const TreePatternNode *N,
   // the "outs" list.
   unsigned NumResults = Inst.getNumResults();
 
-  // Loop over all of the operands of the instruction pattern, emitting code
+  // Number of operands we know the output instruction must have. If it is
-  // to fill them all in.  The node 'N' usually has number children equal to
+  // variadic, we could have more operands.
-  // the number of input operands of the instruction.  However, in cases
+  unsigned NumFixedOperands = II.Operands.size();
-  // where there are predicate operands for an instruction, we need to fill
-  // in the 'execute always' values.  Match up the node operands to the
-  // instruction operands to do this.
-  SmallVector<unsigned, 8> InstOps;
-  for (unsigned ChildNo = 0, InstOpNo = NumResults, e = II.Operands.size();
-       InstOpNo != e; ++InstOpNo) {
 
+  SmallVector<unsigned, 8> InstOps;
+
+  // Loop over all of the fixed operands of the instruction pattern, emitting
+  // code to fill them all in. The node 'N' usually has number children equal to
+  // the number of input operands of the instruction.  However, in cases where
+  // there are predicate operands for an instruction, we need to fill in the
+  // 'execute always' values. Match up the node operands to the instruction
+  // operands to do this.
+  unsigned ChildNo = 0;
+  for (unsigned InstOpNo = NumResults, e = NumFixedOperands;
+       InstOpNo != e; ++InstOpNo) {
     // Determine what to emit for this operand.
     Record *OperandNode = II.Operands[InstOpNo].Rec;
     if (OperandNode->isSubClassOf("OperandWithDefaultOps") &&
@@ -807,6 +812,16 @@ EmitResultInstructionAsOperand(const TreePatternNode *N,
     }
   }
 
+  // If this is a variadic output instruction (i.e. REG_SEQUENCE), we can't
+  // expand suboperands, use default operands, or other features determined from
+  // the CodeGenInstruction after the fixed operands, which were handled
+  // above. Emit the remaining instructions implicitly added by the use for
+  // variable_ops.
+  if (II.Operands.isVariadic) {
+    for (unsigned I = ChildNo, E = N->getNumChildren(); I < E; ++I)
+      EmitResultOperand(N->getChild(I), InstOps);
+  }
+
   // If this node has input glue or explicitly specified input physregs, we
   // need to add chained and glued copyfromreg nodes and materialize the glue
   // input.
@@ -852,7 +867,7 @@ EmitResultInstructionAsOperand(const TreePatternNode *N,
   // gets the excess operands from the input DAG.
   int NumFixedArityOperands = -1;
   if (isRoot &&
-      (Pattern.getSrcPattern()->NodeHasProperty(SDNPVariadic, CGP)))
+      Pattern.getSrcPattern()->NodeHasProperty(SDNPVariadic, CGP))
     NumFixedArityOperands = Pattern.getSrcPattern()->getNumChildren();
 
   // If this is the root node and multiple matched nodes in the input pattern