Simplify RegScavenger::forward a bit more.

Verify that early clobber registers and their aliases are not used.

All changes to RegsAvailable are now done as a transaction so the order of
operands makes no difference.

The included test case is from PR4686. It has behaviour that was dependent on the order of operands.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@78465 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 7 insertions, 1 deletions

diff --git a/include/llvm/CodeGen/RegisterScavenging.h b/include/llvm/CodeGen/RegisterScavenging.h
index b0bcc6724e..478da3d142 100644
--- a/include/llvm/CodeGen/RegisterScavenging.h
+++ b/include/llvm/CodeGen/RegisterScavenging.h
@@ -162,8 +162,14 @@ private:
   MachineInstr *findFirstUse(MachineBasicBlock *MBB,
                              MachineBasicBlock::iterator I, unsigned Reg,
                              unsigned &Dist);
+
+  /// Add Reg and all its sub-registers to BV.
+  void addRegWithSubRegs(BitVector &BV, unsigned Reg);
+
+  /// Add Reg and its aliases to BV.
+  void addRegWithAliases(BitVector &BV, unsigned Reg);
 };
- 
+
 } // End llvm namespace
 
 #endif