TableGen: Add support of Intrinsics with multiple returns

[wenbos]

Summary

This patch deals with intrinsics with multiple outputs, for example load instrinsic with address updated.

DAG selection for Instrinsics could be done either through source code or tablegen. Handling all intrinsics in source code would introduce a huge chunk of repetitive code if we have a large number of intrinsic that return multiple values (see NVPTX as an example). While intrinsic class in tablegen supports multiple outputs, tablegen only supports Intrinsics with zero or one output on TreePattern. This appears to be a simple bug in tablegen that is fixed by this patch.

Intrinsics is defined as:

def int_xxx_load_addr_updated: Intrinsic<[llvm_i32_ty, llvm_ptr_ty], [llvm_ptr_ty, llvm_i32_ty], []>;

Instruction will be defined as:

def L32_X: Inst<(outs reg:$d1, reg:$d2), (ins reg:$s1, reg:$s2), "ld32_x $d1, $d2, $s2", [(set i32:$d1, i32:$d2, (int_xxx_load_addr_updated i32:$s1, i32:$s2))]>;

[hfinkel]

utils/TableGen/CodeGenDAGPatterns.cpp

2208 ↗

(On Diff #97897)

Can you please add a comment explaining why GetNumNodeResults need to be called here (and not, say, below, where it is now).

[wenbos]

new comments were added

[wenbos]

utils/TableGen/CodeGenDAGPatterns.cpp

2208 ↗

(On Diff #97897)

Hi Hal, comments are added in latest patch.

[hfinkel]

Does matching instructions with multiple outputs now work except for this intrinsics problem, or is further work necessary to support this in general?

utils/TableGen/CodeGenDAGPatterns.cpp

2208 ↗

(On Diff #98403)

covert -> convert, and some grammar improvements:

// Get the actual number of results before Operator is converted to an intrinsic node (which is hard-coded to have either zero or one result).

[wenbos]

In D32888#768451, @hfinkel wrote:

Does matching instructions with multiple outputs now work except for this intrinsics problem, or is further work necessary to support this in general?

Yes, it works now.

[wenbos]

comments are updated

[hfinkel]

LGTM

[wenbos]

Hi Hal, can you commit it since I have no commit access?

[amehsan]

In D32888#771149, @wenbos wrote:

Hi Hal, can you commit it since I have no commit access?

Wenbo, I will commit this.

[wenbos]

In D32888#778254, @amehsan wrote:

In D32888#771149, @wenbos wrote:

Hi Hal, can you commit it since I have no commit access?

Wenbo, I will commit this.

Thx a lot, Ehsan.

llvm/trunk/utils/TableGen/CodeGenDAGPatterns.cpp

TreePatternNode *TreePattern::ParseTreePattern(Init *TheInit, StringRef OpName){
   }
 
   std::vector<TreePatternNode*> Children;
 
   // Parse all the operands.
   for (unsigned i = 0, e = Dag->getNumArgs(); i != e; ++i)
     Children.push_back(ParseTreePattern(Dag->getArg(i), Dag->getArgNameStr(i)));
 
+  // Get the actual number of results before Operator is converted to an intrinsic
+  // node (which is hard-coded to have either zero or one result).
+  unsigned NumResults = GetNumNodeResults(Operator, CDP);
+
   // If the operator is an intrinsic, then this is just syntactic sugar for for
   // (intrinsic_* <number>, ..children..).  Pick the right intrinsic node, and
   // convert the intrinsic name to a number.
   if (Operator->isSubClassOf("Intrinsic")) {
     const CodeGenIntrinsic &Int = getDAGPatterns().getIntrinsic(Operator);
     unsigned IID = getDAGPatterns().getIntrinsicID(Operator)+1;
 
     // If this intrinsic returns void, it must have side-effects and thus a
for (unsigned i = 0; i < Children.size(); ++i) {
         if (PrevOp->getValue() != OperandId)
           error("All ComplexPattern operands must appear consistently: "
                 "in the same order in just one ComplexPattern instance.");
       } else
         ComplexPatternOperands[Child->getName()] = OperandId;
     }
   }
 
-  unsigned NumResults = GetNumNodeResults(Operator, CDP);
   TreePatternNode *Result = new TreePatternNode(Operator, Children, NumResults);
   Result->setName(OpName);
 
   if (Dag->getName()) {
     assert(Result->getName().empty());
     Result->setName(Dag->getNameStr());
   }
   return Result;