Change eliminateCallFramePseudoInstr() to return an iterator

This will become necessary in a subsequent change to make this method
merge adjacent stack adjustments, i.e. it might erase the previous
and/or next instruction.

It also greatly simplifies the calls to this function from Prolog-
EpilogInserter. Previously, that had a bunch of logic to resume iteration
after the call; now it just continues with the returned iterator.

Note that this changes the behaviour of PEI a little. Previously,
it attempted to re-visit the new instruction created by
eliminateCallFramePseudoInstr(). That code was added in r36625,
but I can't see any reason for it: the new instructions will obviously
not be pseudo instructions, they will not have FrameIndex operands,
and we have already accounted for the stack adjustment.

Differential Revision: http://reviews.llvm.org/D18627

llvm-svn: 265036

1 files changed, 2 insertions, 2 deletions

diff --git a/llvm/lib/Target/SystemZ/SystemZFrameLowering.cpp b/llvm/lib/Target/SystemZ/SystemZFrameLowering.cpp
index e1b20d0536d..ebf880eac0a 100644
--- a/llvm/lib/Target/SystemZ/SystemZFrameLowering.cpp
+++ b/llvm/lib/Target/SystemZ/SystemZFrameLowering.cpp
@@ -511,7 +511,7 @@ SystemZFrameLowering::hasReservedCallFrame(const MachineFunction &MF) const {
   return true;
 }
 
-void SystemZFrameLowering::
+MachineBasicBlock::iterator SystemZFrameLowering::
 eliminateCallFramePseudoInstr(MachineFunction &MF,
                               MachineBasicBlock &MBB,
                               MachineBasicBlock::iterator MI) const {
@@ -520,7 +520,7 @@ eliminateCallFramePseudoInstr(MachineFunction &MF,
   case SystemZ::ADJCALLSTACKUP:
     assert(hasReservedCallFrame(MF) &&
            "ADJSTACKDOWN and ADJSTACKUP should be no-ops");
-    MBB.erase(MI);
+    return MBB.erase(MI);
     break;
 
   default: