6502/llvm-6502
1
0
Fork 0
mirror of https://github.com/c64scene-ar/llvm-6502.git synced 2025-07-25 13:24:46 +00:00
Code Issues Projects Releases Wiki Activity

Move 3 "(add (select cc, 0, c), x) -> (select cc, x, (add, x, c))"

Browse Source 
related transformations out of target-specific dag combine into the
ARM backend.  These were added by Evan in r37685 with no testcases
and only seems to help ARM (e.g. test/CodeGen/ARM/select_xform.ll).

Add some simple X86-specific (for now) DAG combines that turn things
like cond ? 8 : 0  -> (zext(cond) << 3).  This happens frequently
with the recently added cp constant select optimization, but is a
very general xform.  For example, we now compile the second example
in const-select.ll to:

_test:
        movsd   LCPI2_0, %xmm0
        ucomisd 8(%esp), %xmm0
        seta    %al
        movzbl  %al, %eax
        movl    4(%esp), %ecx
        movsbl  (%ecx,%eax,4), %eax
        ret

instead of:

_test:
        movl    4(%esp), %eax
        leal    4(%eax), %ecx
        movsd   LCPI2_0, %xmm0
        ucomisd 8(%esp), %xmm0
        cmovbe  %eax, %ecx
        movsbl  (%ecx), %eax
        ret

This passes multisource and dejagnu.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@66779 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Chris Lattner
2009-03-12 06:52:53 +00:00
parent 2b9f434908
commit d1980a5acd
6 changed files with 213 additions and 105 deletions
Download Patch File Download Diff File Expand all files Collapse all files

80
lib/CodeGen/SelectionDAG/DAGCombiner.cpp
View File

@@ -543,8 +543,10 @@ SDValue DAGCombiner::CombineTo(SDNode *N, const SDValue *To, unsigned NumTo,
if (AddTo) {
// Push the new nodes and any users onto the worklist
for (unsigned i = 0, e = NumTo; i != e; ++i) {
AddToWorkList(To[i].getNode());
AddUsersToWorkList(To[i].getNode());
if (To[i].getNode()) {
AddToWorkList(To[i].getNode());
AddUsersToWorkList(To[i].getNode());
}
}
}
@@ -944,65 +946,6 @@ SDValue combineShlAddConstant(DebugLoc DL, SDValue N0, SDValue N1,
return SDValue();
}
static
SDValue combineSelectAndUse(SDNode *N, SDValue Slct, SDValue OtherOp,
SelectionDAG &DAG, const TargetLowering &TLI,
bool LegalOperations) {
MVT VT = N->getValueType(0);
unsigned Opc = N->getOpcode();
bool isSlctCC = Slct.getOpcode() == ISD::SELECT_CC;
SDValue LHS = isSlctCC ? Slct.getOperand(2) : Slct.getOperand(1);
SDValue RHS = isSlctCC ? Slct.getOperand(3) : Slct.getOperand(2);
ISD::CondCode CC = ISD::SETCC_INVALID;
if (isSlctCC) {
CC = cast<CondCodeSDNode>(Slct.getOperand(4))->get();
} else {
SDValue CCOp = Slct.getOperand(0);
if (CCOp.getOpcode() == ISD::SETCC)
CC = cast<CondCodeSDNode>(CCOp.getOperand(2))->get();
}
bool DoXform = false;
bool InvCC = false;
assert ((Opc == ISD::ADD || (Opc == ISD::SUB && Slct == N->getOperand(1))) &&
"Bad input!");
if (LHS.getOpcode() == ISD::Constant &&
cast<ConstantSDNode>(LHS)->isNullValue()) {
DoXform = true;
} else if (CC != ISD::SETCC_INVALID &&
RHS.getOpcode() == ISD::Constant &&
cast<ConstantSDNode>(RHS)->isNullValue()) {
std::swap(LHS, RHS);
SDValue Op0 = Slct.getOperand(0);
MVT OpVT = isSlctCC ? Op0.getValueType() :
Op0.getOperand(0).getValueType();
bool isInt = OpVT.isInteger();
CC = ISD::getSetCCInverse(CC, isInt);
if (LegalOperations && !TLI.isCondCodeLegal(CC, OpVT))
return SDValue(); // Inverse operator isn't legal.
DoXform = true;
InvCC = true;
}
if (DoXform) {
SDValue Result = DAG.getNode(Opc, RHS.getDebugLoc(), VT, OtherOp, RHS);
if (isSlctCC)
return DAG.getSelectCC(N->getDebugLoc(), OtherOp, Result,
Slct.getOperand(0), Slct.getOperand(1), CC);
SDValue CCOp = Slct.getOperand(0);
if (InvCC)
CCOp = DAG.getSetCC(Slct.getDebugLoc(), CCOp.getValueType(),
CCOp.getOperand(0), CCOp.getOperand(1), CC);
return DAG.getNode(ISD::SELECT, N->getDebugLoc(), VT,
CCOp, OtherOp, Result);
}
return SDValue();
}
SDValue DAGCombiner::visitADD(SDNode *N) {
SDValue N0 = N->getOperand(0);
SDValue N1 = N->getOperand(1);
@@ -1123,16 +1066,6 @@ SDValue DAGCombiner::visitADD(SDNode *N) {
if (Result.getNode()) return Result;
}
// fold (add (select cc, 0, c), x) -> (select cc, x, (add, x, c))
if (N0.getOpcode() == ISD::SELECT && N0.getNode()->hasOneUse()) {
SDValue Result = combineSelectAndUse(N, N0, N1, DAG, TLI, LegalOperations);
if (Result.getNode()) return Result;
}
if (N1.getOpcode() == ISD::SELECT && N1.getNode()->hasOneUse()) {
SDValue Result = combineSelectAndUse(N, N1, N0, DAG, TLI, LegalOperations);
if (Result.getNode()) return Result;
}
return SDValue();
}
@@ -1246,11 +1179,6 @@ SDValue DAGCombiner::visitSUB(SDNode *N) {
N0.getOperand(1).getOperand(1) == N1)
return DAG.getNode(ISD::SUB, N->getDebugLoc(), VT,
N0.getOperand(0), N0.getOperand(1).getOperand(0));
// fold (sub x, (select cc, 0, c)) -> (select cc, x, (sub, x, c))
if (N1.getOpcode() == ISD::SELECT && N1.getNode()->hasOneUse()) {
SDValue Result = combineSelectAndUse(N, N1, N0, DAG, TLI, LegalOperations);
if (Result.getNode()) return Result;
}
// If either operand of a sub is undef, the result is undef
if (N0.getOpcode() == ISD::UNDEF)