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Fix subreg value numbers in handleMoveUp 

The problem can occur in presence of subregs. If we are swapping two
instructions defining different subregs of the same register we will
get a new liveout from a block. We need to preserve value number for
block's liveout for successor block's livein to match.

Differential Revision: https://reviews.llvm.org/D30558

llvm-svn: 297534
This commit is contained in:
Stanislav Mekhanoshin 2017-03-11 00:14:52 +00:00
parent 31d01baa9f
commit b546174b0e
2 changed files with 21 additions and 1 deletions
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4
llvm/lib/CodeGen/LiveIntervalAnalysis.cpp
View File

@ -1232,10 +1232,12 @@ private:
LiveRange::iterator NewIdxIn = NewIdxOut;
assert(NewIdxIn == LR.find(NewIdx.getBaseIndex()));
const SlotIndex SplitPos = NewIdxDef;
OldIdxVNI = OldIdxIn->valno;
// Merge the OldIdxIn and OldIdxOut segments into OldIdxOut.
OldIdxOut->valno->def = OldIdxIn->start;
*OldIdxOut = LiveRange::Segment(OldIdxIn->start, OldIdxOut->end,
OldIdxIn->valno);
OldIdxOut->valno);
// OldIdxIn and OldIdxVNI are now undef and can be overridden.
// We Slide [NewIdxIn, OldIdxIn) down one position.
// |- X0/NewIdxIn -| ... |- Xn-1 -||- Xn/OldIdxIn -||- OldIdxOut -|

18
llvm/unittests/MI/LiveIntervalTest.cpp
View File

@ -382,6 +382,24 @@ TEST(LiveIntervalTest, SubRegMoveDown) {
});
}
TEST(LiveIntervalTest, SubRegMoveUp) {
// handleMoveUp had a bug not updating valno of segment incoming to bb.2
// after swapping subreg definitions.
liveIntervalTest(R"MIR(
successors: %bb.1, %bb.2
undef %0.sub0 = IMPLICIT_DEF
%0.sub1 = IMPLICIT_DEF
S_CBRANCH_VCCNZ %bb.2, implicit undef %vcc
S_BRANCH %bb.1
bb.1:
S_NOP 0, implicit %0.sub1
bb.2:
S_NOP 0, implicit %0.sub1
)MIR", [](MachineFunction &MF, LiveIntervals &LIS) {
testHandleMove(MF, LIS, 1, 0);
});
}
int main(int argc, char **argv) {
::testing::InitGoogleTest(&argc, argv);
initLLVM();