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Compile this:

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void %X(int %A) {
        %C = setlt int %A, 123          ; <bool> [#uses=1]
        br bool %C, label %T, label %F

T:              ; preds = %0
        call int %main( int 0 )         ; <int>:0 [#uses=0]
        ret void

F:              ; preds = %0
        ret void
}

to this:

X:
        save -96, %o6, %o6
        subcc %i0, 122, %l0
        bg .LBBX_2      ! F
        nop
...

not this:

X:
        save -96, %o6, %o6
        sethi 0, %l0
        or %g0, 1, %l1
        subcc %i0, 122, %l2
        bg .LBBX_4      !
        nop
.LBBX_3:        !
        or %g0, %l0, %l1
.LBBX_4:        !
        subcc %l1, 0, %l0
        bne .LBBX_2     ! F
        nop

llvm-svn: 25833
This commit is contained in:
Chris Lattner 2006-01-31 05:05:52 +00:00
parent d33e8efd56
commit 9d29548015
1 changed files with 37 additions and 21 deletions
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58
lib/Target/SparcV8/SparcV8ISelDAGToDAG.cpp
View File

@ -735,6 +735,28 @@ LowerFrameReturnAddress(bool isFrameAddr, SDOperand Chain, unsigned Depth,
abort();
}
// Look at LHS/RHS/CC and see if they are a lowered V8 setcc instruction. If so
// set LHS/RHS and V8CC to the LHS/RHS of the setcc and V8CC to the condition.
static void LookThroughSetCC(SDOperand &LHS, SDOperand &RHS,
ISD::CondCode CC, unsigned &V8CC) {
if (isa<ConstantSDNode>(RHS) && cast<ConstantSDNode>(RHS)->getValue() == 0 &&
CC == ISD::SETNE &&
((LHS.getOpcode() == V8ISD::SELECT_ICC &&
LHS.getOperand(3).getOpcode() == V8ISD::CMPICC) ||
(LHS.getOpcode() == V8ISD::SELECT_FCC &&
LHS.getOperand(3).getOpcode() == V8ISD::CMPFCC)) &&
isa<ConstantSDNode>(LHS.getOperand(0)) &&
isa<ConstantSDNode>(LHS.getOperand(1)) &&
cast<ConstantSDNode>(LHS.getOperand(0))->getValue() == 1 &&
cast<ConstantSDNode>(LHS.getOperand(1))->getValue() == 0) {
SDOperand CMPCC = LHS.getOperand(3);
V8CC = cast<ConstantSDNode>(LHS.getOperand(2))->getValue();
LHS = CMPCC.getOperand(0);
RHS = CMPCC.getOperand(1);
}
}
SDOperand SparcV8TargetLowering::
LowerOperation(SDOperand Op, SelectionDAG &DAG) {
switch (Op.getOpcode()) {
@ -770,8 +792,14 @@ LowerOperation(SDOperand Op, SelectionDAG &DAG) {
SDOperand LHS = Op.getOperand(2);
SDOperand RHS = Op.getOperand(3);
SDOperand Dest = Op.getOperand(4);
unsigned Opc, V8CC = ~0U;
// If this is a br_cc of a "setcc", and if the setcc got lowered into
// an CMP[IF]CC/SELECT_[IF]CC pair, find the original compared values.
LookThroughSetCC(LHS, RHS, CC, V8CC);
// Get the condition flag.
SDOperand CompareFlag;
if (LHS.getValueType() == MVT::i32) {
std::vector<MVT::ValueType> VTs;
VTs.push_back(MVT::i32);
@ -779,14 +807,16 @@ LowerOperation(SDOperand Op, SelectionDAG &DAG) {
std::vector<SDOperand> Ops;
Ops.push_back(LHS);
Ops.push_back(RHS);
SDOperand Cond = DAG.getNode(V8ISD::CMPICC, VTs, Ops).getValue(1);
SDOperand CCN = DAG.getConstant(IntCondCCodeToICC(CC), MVT::i32);
return DAG.getNode(V8ISD::BRICC, MVT::Other, Chain, Dest, CCN, Cond);
CompareFlag = DAG.getNode(V8ISD::CMPICC, VTs, Ops).getValue(1);
if (V8CC == ~0U) V8CC = IntCondCCodeToICC(CC);
Opc = V8ISD::BRICC;
} else {
SDOperand Cond = DAG.getNode(V8ISD::CMPFCC, MVT::Flag, LHS, RHS);
SDOperand CCN = DAG.getConstant(FPCondCCodeToFCC(CC), MVT::i32);
return DAG.getNode(V8ISD::BRFCC, MVT::Other, Chain, Dest, CCN, Cond);
CompareFlag = DAG.getNode(V8ISD::CMPFCC, MVT::Flag, LHS, RHS);
if (V8CC == ~0U) V8CC = FPCondCCodeToFCC(CC);
Opc = V8ISD::BRFCC;
}
return DAG.getNode(Opc, MVT::Other, Chain, Dest,
DAG.getConstant(V8CC, MVT::i32), CompareFlag);
}
case ISD::SELECT_CC: {
SDOperand LHS = Op.getOperand(0);
@ -798,21 +828,7 @@ LowerOperation(SDOperand Op, SelectionDAG &DAG) {
// If this is a select_cc of a "setcc", and if the setcc got lowered into
// an CMP[IF]CC/SELECT_[IF]CC pair, find the original compared values.
if (isa<ConstantSDNode>(RHS) && cast<ConstantSDNode>(RHS)->getValue() == 0&&
CC == ISD::SETNE &&
((LHS.getOpcode() == V8ISD::SELECT_ICC &&
LHS.getOperand(3).getOpcode() == V8ISD::CMPICC) ||
(LHS.getOpcode() == V8ISD::SELECT_FCC &&
LHS.getOperand(3).getOpcode() == V8ISD::CMPFCC)) &&
isa<ConstantSDNode>(LHS.getOperand(0)) &&
isa<ConstantSDNode>(LHS.getOperand(1)) &&
cast<ConstantSDNode>(LHS.getOperand(0))->getValue() == 1 &&
cast<ConstantSDNode>(LHS.getOperand(1))->getValue() == 0) {
SDOperand CMPCC = LHS.getOperand(3);
V8CC = cast<ConstantSDNode>(LHS.getOperand(2))->getValue();
LHS = CMPCC.getOperand(0);
RHS = CMPCC.getOperand(1);
}
LookThroughSetCC(LHS, RHS, CC, V8CC);
SDOperand CompareFlag;
if (LHS.getValueType() == MVT::i32) {