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Extend TableGen instruction selection matcher to improve handling

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of complex instruction operands (e.g. address modes).

Currently, if a Pat pattern creates an instruction that has a complex
operand (i.e. one that consists of multiple sub-operands at the MI
level), this operand must match a ComplexPattern DAG pattern with the
correct number of output operands.

This commit extends TableGen to alternatively allow match a complex
operands against multiple separate operands at the DAG level.

This allows using Pat patterns to match pre-increment nodes like
pre_store (which must have separate operands at the DAG level) onto
an instruction pattern that uses a multi-operand memory operand,
like the following example on PowerPC (will be committed as a
follow-on patch):

  def STWU  : DForm_1<37, (outs ptr_rc:$ea_res), (ins GPRC:$rS, memri:$dst),
                    "stwu $rS, $dst", LdStStoreUpd, []>,
                    RegConstraint<"$dst.reg = $ea_res">, NoEncode<"$ea_res">;

  def : Pat<(pre_store GPRC:$rS, ptr_rc:$ptrreg, iaddroff:$ptroff),
            (STWU GPRC:$rS, iaddroff:$ptroff, ptr_rc:$ptrreg)>;

Here, the pair of "ptroff" and "ptrreg" operands is matched onto the
complex operand "dst" of class "memri" in the "STWU" instruction.

Approved by Jakob Stoklund Olesen.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@177428 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Ulrich Weigand
2013-03-19 19:51:09 +00:00
parent 880d82e3db
commit ec8d1a5b72
3 changed files with 78 additions and 11 deletions
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38
utils/TableGen/CodeGenDAGPatterns.cpp
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@ -1654,8 +1654,42 @@ bool TreePatternNode::ApplyTypeConstraints(TreePattern &TP, bool NotRegisters) {
TreePatternNode *Child = getChild(ChildNo++);
unsigned ChildResNo = 0; // Instructions always use res #0 of their op.
// If the operand has sub-operands, they may be provided by distinct
// child patterns, so attempt to match each sub-operand separately.
if (OperandNode->isSubClassOf("Operand")) {
DagInit *MIOpInfo = OperandNode->getValueAsDag("MIOperandInfo");
if (unsigned NumArgs = MIOpInfo->getNumArgs()) {
// But don't do that if the whole operand is being provided by
// a single ComplexPattern.
const ComplexPattern *AM = Child->getComplexPatternInfo(CDP);
if (!AM || AM->getNumOperands() < NumArgs) {
// Match first sub-operand against the child we already have.
Record *SubRec = cast<DefInit>(MIOpInfo->getArg(0))->getDef();
MadeChange |=
Child->UpdateNodeTypeFromInst(ChildResNo, SubRec, TP);
// And the remaining sub-operands against subsequent children.
for (unsigned Arg = 1; Arg < NumArgs; ++Arg) {
if (ChildNo >= getNumChildren()) {
TP.error("Instruction '" + getOperator()->getName() +
"' expects more operands than were provided.");
return false;
}
Child = getChild(ChildNo++);
SubRec = cast<DefInit>(MIOpInfo->getArg(Arg))->getDef();
MadeChange |=
Child->UpdateNodeTypeFromInst(ChildResNo, SubRec, TP);
}
continue;
}
}
}
// If we didn't match by pieces above, attempt to match the whole
// operand now.
MadeChange |= Child->UpdateNodeTypeFromInst(ChildResNo, OperandNode, TP);
MadeChange |= Child->ApplyTypeConstraints(TP, NotRegisters);
}
if (ChildNo != getNumChildren()) {
@ -1664,6 +1698,8 @@ bool TreePatternNode::ApplyTypeConstraints(TreePattern &TP, bool NotRegisters) {
return false;
}
for (unsigned i = 0, e = getNumChildren(); i != e; ++i)
MadeChange |= getChild(i)->ApplyTypeConstraints(TP, NotRegisters);
return MadeChange;
}