Stop fixing bad machine code in LiveIntervalAnalysis.
The first def of a virtual register cannot also read the register.
Assert on such bad machine code instead of trying to fix it.
TwoAddressInstructionPass should never create code like that.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@152010 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/LiveIntervalAnalysis.cpp b/lib/CodeGen/LiveIntervalAnalysis.cpp
index 3e16efa..70ed1c3 100644
--- a/lib/CodeGen/LiveIntervalAnalysis.cpp
+++ b/lib/CodeGen/LiveIntervalAnalysis.cpp
@@ -187,21 +187,9 @@
// Get the Idx of the defining instructions.
SlotIndex defIndex = MIIdx.getRegSlot(MO.isEarlyClobber());
- // Make sure the first definition is not a partial redefinition. Add an
- // <imp-def> of the full register.
- // FIXME: LiveIntervals shouldn't modify the code like this. Whoever
- // created the machine instruction should annotate it with <undef> flags
- // as needed. Then we can simply assert here. The REG_SEQUENCE lowering
- // is the main suspect.
- if (MO.getSubReg()) {
- mi->addRegisterDefined(interval.reg);
- // Mark all defs of interval.reg on this instruction as reading <undef>.
- for (unsigned i = MOIdx, e = mi->getNumOperands(); i != e; ++i) {
- MachineOperand &MO2 = mi->getOperand(i);
- if (MO2.isReg() && MO2.getReg() == interval.reg && MO2.getSubReg())
- MO2.setIsUndef();
- }
- }
+ // Make sure the first definition is not a partial redefinition.
+ assert(!MO.readsReg() && "First def cannot also read virtual register "
+ "missing <undef> flag?");
VNInfo *ValNo = interval.getNextValue(defIndex, VNInfoAllocator);
assert(ValNo->id == 0 && "First value in interval is not 0?");