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When lowering SELECT_CC, see if the input is a lowered SETCC. If so, fold

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the two operations together.  This allows us to compile this:

void %two(int %a, int* %b) {
        %tmp.2 = seteq int %a, 0
        %tmp.0.0 = select bool %tmp.2, int 10, int 20
        store int %tmp.0.0, int* %b
        ret void
}

into:

two:
        save -96, %o6, %o6
        or %g0, 20, %l0
        or %g0, 10, %l1
        subcc %i0, 0, %l2
        be .LBBtwo_2    ! entry
        nop
.LBBtwo_1:      ! entry
        or %g0, %l0, %l1
.LBBtwo_2:      ! entry
        st %l1, [%i1]
        restore %g0, %g0, %g0
        retl
        nop

instead of:

two:
        save -96, %o6, %o6
        sethi 0, %l0
        or %g0, 1, %l1
        or %g0, 20, %l2
        or %g0, 10, %l3
        subcc %i0, 0, %l4
        be .LBBtwo_2    ! entry
        nop
.LBBtwo_1:      ! entry
        or %g0, %l0, %l1
.LBBtwo_2:      ! entry
        subcc %l1, 0, %l0
        bne .LBBtwo_4   ! entry
        nop
.LBBtwo_3:      ! entry
        or %g0, %l2, %l3
.LBBtwo_4:      ! entry
        st %l3, [%i1]
        restore %g0, %g0, %g0
        retl
        nop


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@25806 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Chris Lattner
2006-01-30 04:34:44 +00:00
parent 85046901b8
commit dea9528f7f
2 changed files with 36 additions and 0 deletions
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18
lib/Target/Sparc/SparcISelDAGToDAG.cpp
View File

@@ -669,6 +669,24 @@ LowerOperation(SDOperand Op, SelectionDAG &DAG) {
SDOperand TrueVal = Op.getOperand(2);
SDOperand FalseVal = Op.getOperand(3);
// 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);
CC = cast<ConstantSDNode>(LHS.getOperand(2))->getValue();
LHS = CMPCC.getOperand(0);
RHS = CMPCC.getOperand(1);
}
SDOperand CompareFlag;
unsigned Opc;
if (LHS.getValueType() == MVT::i32) {

18
lib/Target/SparcV8/SparcV8ISelDAGToDAG.cpp
View File

@@ -669,6 +669,24 @@ LowerOperation(SDOperand Op, SelectionDAG &DAG) {
SDOperand TrueVal = Op.getOperand(2);
SDOperand FalseVal = Op.getOperand(3);
// 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);
CC = cast<ConstantSDNode>(LHS.getOperand(2))->getValue();
LHS = CMPCC.getOperand(0);
RHS = CMPCC.getOperand(1);
}
SDOperand CompareFlag;
unsigned Opc;
if (LHS.getValueType() == MVT::i32) {