Allow a register to be redefined multiple times in a basic block.
LiveVariableAnalysis was a bit picky about a register only being redefined once,
but that really isn't necessary.
Here is an example of chained INSERT_SUBREGs that we can handle now:
68 %reg1040<def> = INSERT_SUBREG %reg1040, %reg1028<kill>, 14
register: %reg1040 +[70,134:0)
76 %reg1040<def> = INSERT_SUBREG %reg1040, %reg1029<kill>, 13
register: %reg1040 replace range with [70,78:1) RESULT: %reg1040,0.000000e+00 = [70,78:1)[78,134:0) 0@78-(134) 1@70-(78)
84 %reg1040<def> = INSERT_SUBREG %reg1040, %reg1030<kill>, 12
register: %reg1040 replace range with [78,86:2) RESULT: %reg1040,0.000000e+00 = [70,78:1)[78,86:2)[86,134:0) 0@86-(134) 1@70-(78) 2@78-(86)
92 %reg1040<def> = INSERT_SUBREG %reg1040, %reg1031<kill>, 11
register: %reg1040 replace range with [86,94:3) RESULT: %reg1040,0.000000e+00 = [70,78:1)[78,86:2)[86,94:3)[94,134:0) 0@94-(134) 1@70-(78) 2@78-(86) 3@86-(94)
rdar://problem/8096390
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@106152 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/LiveIntervalAnalysis.cpp b/lib/CodeGen/LiveIntervalAnalysis.cpp
index 349ea2c..22d6252 100644
--- a/lib/CodeGen/LiveIntervalAnalysis.cpp
+++ b/lib/CodeGen/LiveIntervalAnalysis.cpp
@@ -434,11 +434,6 @@
// are actually two values in the live interval. Because of this we
// need to take the LiveRegion that defines this register and split it
// into two values.
- // Two-address vregs should always only be redefined once. This means
- // that at this point, there should be exactly one value number in it.
- assert((PartReDef || interval.containsOneValue()) &&
- "Unexpected 2-addr liveint!");
- SlotIndex DefIndex = interval.getValNumInfo(0)->def.getDefIndex();
SlotIndex RedefIndex = MIIdx.getDefIndex();
if (MO.isEarlyClobber())
RedefIndex = MIIdx.getUseIndex();
@@ -446,8 +441,9 @@
const LiveRange *OldLR =
interval.getLiveRangeContaining(RedefIndex.getUseIndex());
VNInfo *OldValNo = OldLR->valno;
+ SlotIndex DefIndex = OldValNo->def.getDefIndex();
- // Delete the initial value, which should be short and continuous,
+ // Delete the previous value, which should be short and continuous,
// because the 2-addr copy must be in the same MBB as the redef.
interval.removeRange(DefIndex, RedefIndex);