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Compile: 

int test3(int a, int b) { return (a < 0) ? a : 0; }

to:

_test3:
        srawi r2, r3, 31
        and r3, r2, r3
        blr

instead of:

_test3:
        cmpwi cr0, r3, 1
        li r2, 0
        blt cr0, LBB2_2 ;entry
LBB2_1: ;entry
        mr r3, r2
LBB2_2: ;entry
        blr


This implements: PowerPC/select_lt0.ll:seli32_a_a

llvm-svn: 30517
This commit is contained in:
Chris Lattner 2006-09-20 06:41:35 +00:00
parent 2b09e1d2fc
commit c8cd62d381
1 changed files with 4 additions and 3 deletions
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7
llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
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@ -3168,7 +3168,6 @@ SDOperand DAGCombiner::SimplifySelectCC(SDOperand N0, SDOperand N1,
ISD::CondCode CC) {
MVT::ValueType VT = N2.getValueType();
//ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0.Val);
ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1.Val);
ConstantSDNode *N2C = dyn_cast<ConstantSDNode>(N2.Val);
ConstantSDNode *N3C = dyn_cast<ConstantSDNode>(N3.Val);
@ -3204,9 +3203,11 @@ SDOperand DAGCombiner::SimplifySelectCC(SDOperand N0, SDOperand N1,
// Check to see if we can perform the "gzip trick", transforming
// select_cc setlt X, 0, A, 0 -> and (sra X, size(X)-1), A
if (N1C && N1C->isNullValue() && N3C && N3C->isNullValue() &&
if (N1C && N3C && N3C->isNullValue() && CC == ISD::SETLT &&
MVT::isInteger(N0.getValueType()) &&
MVT::isInteger(N2.getValueType()) && CC == ISD::SETLT) {
MVT::isInteger(N2.getValueType()) &&
(N1C->isNullValue() || // (a < 0) ? b : 0
(N1C->getValue() == 1 && N0 == N2))) { // (a < 1) ? a : 0
MVT::ValueType XType = N0.getValueType();
MVT::ValueType AType = N2.getValueType();
if (XType >= AType) {