Re-apply 55467 with fix. If copy is being replaced by remat'ed def, transfer the implicit defs onto the remat'ed instruction.

llvm-svn: 55564

1 files changed, 7 insertions, 0 deletions

diff --git a/llvm/lib/CodeGen/SimpleRegisterCoalescing.h b/llvm/lib/CodeGen/SimpleRegisterCoalescing.h
index bb21515a354..62738952aa2 100644
--- a/llvm/lib/CodeGen/SimpleRegisterCoalescing.h
+++ b/llvm/lib/CodeGen/SimpleRegisterCoalescing.h
@@ -96,6 +96,10 @@ namespace llvm {
     ///
     SmallPtrSet<MachineInstr*, 32> JoinedCopies;
 
+    /// ReMatCopies - Keep track of copies eliminated due to remat.
+    ///
+    SmallPtrSet<MachineInstr*, 32> ReMatCopies;
+
   public:
     static char ID; // Pass identifcation, replacement for typeid
     SimpleRegisterCoalescing() : MachineFunctionPass((intptr_t)&ID) {}
@@ -194,6 +198,9 @@ namespace llvm {
     bool RemoveCopyByCommutingDef(LiveInterval &IntA, LiveInterval &IntB,
                                   MachineInstr *CopyMI);
 
+    bool ReMaterializeTrivialDef(LiveInterval &SrcInt, unsigned DstReg,
+                                 MachineInstr *CopyMI);
+
     /// TurnCopyIntoImpDef - If source of the specified copy is an implicit def,
     /// turn the copy into an implicit def.
     bool TurnCopyIntoImpDef(MachineBasicBlock::iterator &I,