Turns out AnalyzeBranch can modify the mbb being analyzed. This is a nasty

suprise to some callers, e.g. register coalescer. For now, add an parameter
that tells AnalyzeBranch whether it's safe to modify the mbb. A better
solution is out there, but I don't have time to deal with it right now.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@64124 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 5 insertions, 1 deletions

diff --git a/include/llvm/Target/TargetInstrInfo.h b/include/llvm/Target/TargetInstrInfo.h
index 6f8eb1c..1ea4a96 100644
--- a/include/llvm/Target/TargetInstrInfo.h
+++ b/include/llvm/Target/TargetInstrInfo.h
@@ -195,9 +195,13 @@ public:
   /// Note that RemoveBranch and InsertBranch must be implemented to support
   /// cases where this method returns success.
   ///
+  /// If AllowModify is true, then this routine is allowed to modify the basic
+  /// block (e.g. delete instructions after the unconditional branch).
+  ///
   virtual bool AnalyzeBranch(MachineBasicBlock &MBB, MachineBasicBlock *&TBB,
                              MachineBasicBlock *&FBB,
-                             SmallVectorImpl<MachineOperand> &Cond) const {
+                             SmallVectorImpl<MachineOperand> &Cond,
+                             bool AllowModify = false) const {
     return true;
   }