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[DAG] Reverse node replacement in extension operation. NFCI. 

Reorder replacements to be user first in preparation for multi-level
folding to premptively avoid inadvertantly deleting later nodes from
sharing found from replacement.

llvm-svn: 308348
This commit is contained in:
Nirav Dave 2017-07-18 19:49:20 +00:00
parent 95e45f9f93
commit 041b87758a
1 changed files with 20 additions and 12 deletions
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32
llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
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@ -7172,11 +7172,13 @@ SDValue DAGCombiner::visitSIGN_EXTEND(SDNode *N) {
N0.getValueType(), ExtLoad);
ExtendSetCCUses(SetCCs, Trunc, ExtLoad, DL, ISD::SIGN_EXTEND);
// If the load value is used only by N, replace it via CombineTo N.
if (N0.getValue(0).hasOneUse())
bool NoReplaceTrunc = SDValue(LN0, 0).hasOneUse();
CombineTo(N, ExtLoad);
if (NoReplaceTrunc)
DAG.ReplaceAllUsesOfValueWith(SDValue(LN0, 1), ExtLoad.getValue(1));
else
CombineTo(LN0, Trunc, ExtLoad.getValue(1));
return CombineTo(N, ExtLoad); // Return N so it doesn't get rechecked!
return SDValue(N, 0);
}
}
@ -7233,12 +7235,13 @@ SDValue DAGCombiner::visitSIGN_EXTEND(SDNode *N) {
SDLoc(N0.getOperand(0)),
N0.getOperand(0).getValueType(), ExtLoad);
ExtendSetCCUses(SetCCs, Trunc, ExtLoad, DL, ISD::SIGN_EXTEND);
// If the load value is used only by N, replace it via CombineTo N.
if (SDValue(LN0, 0).hasOneUse())
bool NoReplaceTrunc = SDValue(LN0, 0).hasOneUse();
CombineTo(N, And);
if (NoReplaceTrunc)
DAG.ReplaceAllUsesOfValueWith(SDValue(LN0, 1), ExtLoad.getValue(1));
else
CombineTo(LN0, Trunc, ExtLoad.getValue(1));
return CombineTo(N, And); // Return N so it doesn't get rechecked!
return SDValue(N,0); // Return N so it doesn't get rechecked!
}
}
}
@ -7479,11 +7482,13 @@ SDValue DAGCombiner::visitZERO_EXTEND(SDNode *N) {
N0.getValueType(), ExtLoad);
ExtendSetCCUses(SetCCs, Trunc, ExtLoad, SDLoc(N), ISD::ZERO_EXTEND);
// If the load value is used only by N, replace it via CombineTo N.
if (SDValue(LN0, 0).hasOneUse())
bool NoReplaceTrunc = SDValue(LN0, 0).hasOneUse();
CombineTo(N, ExtLoad);
if (NoReplaceTrunc)
DAG.ReplaceAllUsesOfValueWith(SDValue(LN0, 1), ExtLoad.getValue(1));
else
CombineTo(LN0, Trunc, ExtLoad.getValue(1));
return CombineTo(N, ExtLoad); // Return N so it doesn't get rechecked!
return SDValue(N, 0); // Return N so it doesn't get rechecked!
}
}
@ -7534,12 +7539,13 @@ SDValue DAGCombiner::visitZERO_EXTEND(SDNode *N) {
SDLoc(N0.getOperand(0)),
N0.getOperand(0).getValueType(), ExtLoad);
ExtendSetCCUses(SetCCs, Trunc, ExtLoad, DL, ISD::ZERO_EXTEND);
// If the load value is used only by N, replace it via CombineTo N.
if (SDValue(LN0, 0).hasOneUse())
bool NoReplaceTrunc = SDValue(LN0, 0).hasOneUse();
CombineTo(N, And);
if (NoReplaceTrunc)
DAG.ReplaceAllUsesOfValueWith(SDValue(LN0, 1), ExtLoad.getValue(1));
else
CombineTo(LN0, Trunc, ExtLoad.getValue(1));
return CombineTo(N, And); // Return N so it doesn't get rechecked!
return SDValue(N,0); // Return N so it doesn't get rechecked!
}
}
}
@ -7716,11 +7722,13 @@ SDValue DAGCombiner::visitANY_EXTEND(SDNode *N) {
ExtendSetCCUses(SetCCs, Trunc, ExtLoad, SDLoc(N),
ISD::ANY_EXTEND);
// If the load value is used only by N, replace it via CombineTo N.
if (N0.hasOneUse())
bool NoReplaceTrunc = N0.hasOneUse();
CombineTo(N, ExtLoad);
if (NoReplaceTrunc)
DAG.ReplaceAllUsesOfValueWith(SDValue(LN0, 1), ExtLoad.getValue(1));
else
CombineTo(LN0, Trunc, ExtLoad.getValue(1));
return CombineTo(N, ExtLoad); // Return N so it doesn't get rechecked!
return SDValue(N, 0); // Return N so it doesn't get rechecked!
}
}