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authorEvan Cheng <evan.cheng@apple.com>2010-10-04 22:41:01 +0000
committerEvan Cheng <evan.cheng@apple.com>2010-10-04 22:41:01 +0000
commit2a135ae53057ef7d0e9123d450b958d0d59d8ccc (patch)
treeb25ce125df0bf4e6321a63bfca7a9e9717b08a4c /lib/CodeGen/SelectionDAG/DAGCombiner.cpp
parent48f9543404c965d3cfca16a55b8c237b02486f40 (diff)
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This DAG combine BRCOND transformation can look pass truncate of the operand:
// %a = ... // %b = and i32 %a, 2 // %c = srl i32 %b, 1 // brcond i32 %c ... // // into // // %a = ... // %b = and i32 %a, 2 // %c = setcc eq %b, 0 // brcond %c ... Make sure it restores local variable N1, which corresponds to the condition operand if it fails to match. This apparently breaks TCE but since that backend isn't in the tree I don't have a test for it. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@115571 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'lib/CodeGen/SelectionDAG/DAGCombiner.cpp')
-rw-r--r--lib/CodeGen/SelectionDAG/DAGCombiner.cpp31
1 files changed, 18 insertions, 13 deletions
diff --git a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
index ede54e5..69dbd03 100644
--- a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
+++ b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
@@ -5102,14 +5102,17 @@ SDValue DAGCombiner::visitBRCOND(SDNode *N) {
N1.getOperand(0), N1.getOperand(1), N2);
}
- SDNode *Trunc = 0;
- if (N1.getOpcode() == ISD::TRUNCATE && N1.hasOneUse()) {
- // Look past truncate.
- Trunc = N1.getNode();
- N1 = N1.getOperand(0);
- }
+ if ((N1.hasOneUse() && N1.getOpcode() == ISD::SRL) ||
+ ((N1.getOpcode() == ISD::TRUNCATE && N1.hasOneUse()) &&
+ (N1.getOperand(0).hasOneUse() &&
+ N1.getOperand(0).getOpcode() == ISD::SRL))) {
+ SDNode *Trunc = 0;
+ if (N1.getOpcode() == ISD::TRUNCATE) {
+ // Look pass the truncate.
+ Trunc = N1.getNode();
+ N1 = N1.getOperand(0);
+ }
- if (N1.hasOneUse() && N1.getOpcode() == ISD::SRL) {
// Match this pattern so that we can generate simpler code:
//
// %a = ...
@@ -5164,6 +5167,10 @@ SDValue DAGCombiner::visitBRCOND(SDNode *N) {
}
}
}
+
+ if (Trunc)
+ // Restore N1 if the above transformation doesn't match.
+ N1 = N->getOperand(1);
}
// Transform br(xor(x, y)) -> br(x != y)
@@ -5199,9 +5206,7 @@ SDValue DAGCombiner::visitBRCOND(SDNode *N) {
Equal = true;
}
- SDValue NodeToReplace = Trunc ? SDValue(Trunc, 0) : N1;
-
- EVT SetCCVT = NodeToReplace.getValueType();
+ EVT SetCCVT = N1.getValueType();
if (LegalTypes)
SetCCVT = TLI.getSetCCResultType(SetCCVT);
SDValue SetCC = DAG.getSetCC(TheXor->getDebugLoc(),
@@ -5210,9 +5215,9 @@ SDValue DAGCombiner::visitBRCOND(SDNode *N) {
Equal ? ISD::SETEQ : ISD::SETNE);
// Replace the uses of XOR with SETCC
WorkListRemover DeadNodes(*this);
- DAG.ReplaceAllUsesOfValueWith(NodeToReplace, SetCC, &DeadNodes);
- removeFromWorkList(NodeToReplace.getNode());
- DAG.DeleteNode(NodeToReplace.getNode());
+ DAG.ReplaceAllUsesOfValueWith(N1, SetCC, &DeadNodes);
+ removeFromWorkList(N1.getNode());
+ DAG.DeleteNode(N1.getNode());
return DAG.getNode(ISD::BRCOND, N->getDebugLoc(),
MVT::Other, Chain, SetCC, N2);
}