VirtRegMap: Correctly deal with bundles when deleting identity copies.

This fixes two problems when VirtRegMap encounters bundles:

- When substituting a vreg subregister def with an actual register the
  internal read flag must be cleared.
- Removing an identity COPY from a bundle needs to use
  removeFromBundle() and a newly introduced function to update
  SlotIndexes.

No testcase here, because none of the in-tree targets trigger this,
however an upcoming commit of mine will need this and the testcase there
will trigger this.

Differential Revision: https://reviews.llvm.org/D30925

llvm-svn: 298024

1 files changed, 42 insertions, 0 deletions

diff --git a/llvm/lib/CodeGen/SlotIndexes.cpp b/llvm/lib/CodeGen/SlotIndexes.cpp
index dba103e9bfb..bc2a1d09056 100644
--- a/llvm/lib/CodeGen/SlotIndexes.cpp
+++ b/llvm/lib/CodeGen/SlotIndexes.cpp
@@ -103,6 +103,48 @@ bool SlotIndexes::runOnMachineFunction(MachineFunction &fn) {
   return false;
 }
 
+void SlotIndexes::removeMachineInstrFromMaps(MachineInstr &MI) {
+  assert(!MI.isBundledWithPred() &&
+         "Use removeSingleMachineInstrFromMaps() instread");
+  Mi2IndexMap::iterator mi2iItr = mi2iMap.find(&MI);
+  if (mi2iItr == mi2iMap.end())
+    return;
+
+  SlotIndex MIIndex = mi2iItr->second;
+  IndexListEntry &MIEntry = *MIIndex.listEntry();
+  assert(MIEntry.getInstr() == &MI && "Instruction indexes broken.");
+  mi2iMap.erase(mi2iItr);
+  // FIXME: Eventually we want to actually delete these indexes.
+  MIEntry.setInstr(nullptr);
+}
+
+void SlotIndexes::removeSingleMachineInstrFromMaps(MachineInstr &MI) {
+  Mi2IndexMap::iterator mi2iItr = mi2iMap.find(&MI);
+  if (mi2iItr == mi2iMap.end())
+    return;
+
+  SlotIndex MIIndex = mi2iItr->second;
+  IndexListEntry &MIEntry = *MIIndex.listEntry();
+  assert(MIEntry.getInstr() == &MI && "Instruction indexes broken.");
+  mi2iMap.erase(mi2iItr);
+
+  // When removing the first instruction of a bundle update mapping to next
+  // instruction.
+  if (MI.isBundledWithSucc()) {
+    // Only the first instruction of a bundle should have an index assigned.
+    assert(!MI.isBundledWithPred() && "Should have first bundle isntruction");
+
+    MachineBasicBlock::instr_iterator Next = std::next(MI.getIterator());
+    MachineInstr &NextMI = *Next;
+    MIEntry.setInstr(&NextMI);
+    mi2iMap.insert(std::make_pair(&NextMI, MIIndex));
+    return;
+  } else {
+    // FIXME: Eventually we want to actually delete these indexes.
+    MIEntry.setInstr(nullptr);
+  }
+}
+
 void SlotIndexes::renumberIndexes() {
   // Renumber updates the index of every element of the index list.
   DEBUG(dbgs() << "\n*** Renumbering SlotIndexes ***\n");