Add a FIXME.
TwoAddressInstructionPass should annotate instructions with <undef>
flags when it lower REG_SEQUENCE instructions. LiveIntervals should not
be in the business of modifying code (except for kill flags, perhaps).
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@141187 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/LiveIntervalAnalysis.cpp b/lib/CodeGen/LiveIntervalAnalysis.cpp
index 3d95827..b1e202a 100644
--- a/lib/CodeGen/LiveIntervalAnalysis.cpp
+++ b/lib/CodeGen/LiveIntervalAnalysis.cpp
@@ -304,6 +304,10 @@
// 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>.