Changes in directory llvm/lib/CodeGen/SelectionDAG:
DAGCombiner.cpp updated: 1.99 -> 1.100
---
Log message:
Compile this:
xori r6, r2, 1
rlwinm r6, r6, 0, 31, 31
cmpwi cr0, r6, 0
bne cr0, LBB1_3 ; endif
to this:
rlwinm r6, r2, 0, 31, 31
cmpwi cr0, r6, 0
beq cr0, LBB1_3 ; endif
---
Diffs of the changes: (+26 -0)
DAGCombiner.cpp | 26 ++++++++++++++++++++++++++
1 files changed, 26 insertions(+)
Index: llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
diff -u llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp:1.99
llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp:1.100
--- llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp:1.99 Sun Feb 5 02:23:00 2006
+++ llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp Tue Feb 7 20:13:15 2006
@@ -2544,6 +2544,32 @@
DAG.getConstant(C1 & (~0ULL>>(64-ExtSrcTyBits)),
ExtDstTy),
Cond);
+ } else if ((N1C->getValue() == 0 || N1C->getValue() == 1) &&
+ (Cond == ISD::SETEQ || Cond == ISD::SETNE) &&
+ (N0.getOpcode() == ISD::XOR ||
+ (N0.getOpcode() == ISD::AND &&
+ N0.getOperand(0).getOpcode() == ISD::XOR &&
+ N0.getOperand(1) == N0.getOperand(0).getOperand(1))) &&
+ isa<ConstantSDNode>(N0.getOperand(1)) &&
+ cast<ConstantSDNode>(N0.getOperand(1))->getValue() == 1) {
+ // If this is (X^1) == 0/1, swap the RHS and eliminate the xor. We can
+ // only do this if the top bits are known zero.
+ if (TLI.MaskedValueIsZero(N1,
+ MVT::getIntVTBitMask(N0.getValueType())-1)) {
+ // Okay, get the un-inverted input value.
+ SDOperand Val;
+ if (N0.getOpcode() == ISD::XOR)
+ Val = N0.getOperand(0);
+ else {
+ assert(N0.getOpcode() == ISD::AND &&
+ N0.getOperand(0).getOpcode() == ISD::XOR);
+ // ((X^1)&1)^1 -> X & 1
+ Val = DAG.getNode(ISD::AND, N0.getValueType(),
+ N0.getOperand(0).getOperand(0),
N0.getOperand(1));
+ }
+ return DAG.getSetCC(VT, Val, N1,
+ Cond == ISD::SETEQ ? ISD::SETNE : ISD::SETEQ);
+ }
}
uint64_t MinVal, MaxVal;
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