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LiveRegMatrix: Fix some subreg interference checks

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Surprisingly, one of the three interference checks in LiveRegMatrix was
using the main live range instead of the apropriate subregister range
resulting in unnecessarily conservative results.

llvm-svn: 296722
This commit is contained in:
Matthias Braun
2017-03-02 00:35:08 +00:00
parent 3095856d80
commit dbcf9e2ee4
8 changed files with 55 additions and 30 deletions
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13
llvm/lib/CodeGen/LiveRegMatrix.cpp
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@@ -175,10 +175,10 @@ bool LiveRegMatrix::checkRegUnitInterference(LiveInterval &VirtReg,
return Result;
}
LiveIntervalUnion::Query &LiveRegMatrix::query(LiveInterval &VirtReg,
LiveIntervalUnion::Query &LiveRegMatrix::query(const LiveRange &LR,
unsigned RegUnit) {
LiveIntervalUnion::Query &Q = Queries[RegUnit];
Q.init(UserTag, VirtReg, Matrix[RegUnit]);
Q.init(UserTag, LR, Matrix[RegUnit]);
return Q;
}
@@ -196,9 +196,12 @@ LiveRegMatrix::checkInterference(LiveInterval &VirtReg, unsigned PhysReg) {
return IK_RegUnit;
// Check the matrix for virtual register interference.
for (MCRegUnitIterator Units(PhysReg, TRI); Units.isValid(); ++Units)
if (query(VirtReg, *Units).checkInterference())
return IK_VirtReg;
bool Interference = foreachUnit(TRI, VirtReg, PhysReg,
[&](unsigned Unit, const LiveRange &LR) {
return query(LR, Unit).checkInterference();
});
if (Interference)
return IK_VirtReg;
return IK_Free;
}