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

2 files changed, 6 insertions, 6 deletions

diff --git a/llvm/lib/Target/XCore/XCoreFrameLowering.cpp b/llvm/lib/Target/XCore/XCoreFrameLowering.cpp
index ae493de083b..1d254a956eb 100644
--- a/llvm/lib/Target/XCore/XCoreFrameLowering.cpp
+++ b/llvm/lib/Target/XCore/XCoreFrameLowering.cpp
@@ -482,9 +482,9 @@ restoreCalleeSavedRegisters(MachineBasicBlock &MBB,
 
 // This function eliminates ADJCALLSTACKDOWN,
 // ADJCALLSTACKUP pseudo instructions
-void XCoreFrameLowering::
-eliminateCallFramePseudoInstr(MachineFunction &MF, MachineBasicBlock &MBB,
-                              MachineBasicBlock::iterator I) const {
+MachineBasicBlock::iterator XCoreFrameLowering::eliminateCallFramePseudoInstr(
+    MachineFunction &MF, MachineBasicBlock &MBB,
+    MachineBasicBlock::iterator I) const {
   const XCoreInstrInfo &TII = *MF.getSubtarget<XCoreSubtarget>().getInstrInfo();
   if (!hasReservedCallFrame(MF)) {
     // Turn the adjcallstackdown instruction into 'extsp <amt>' and the
@@ -528,7 +528,7 @@ eliminateCallFramePseudoInstr(MachineFunction &MF, MachineBasicBlock &MBB,
     }
   }
 
-  MBB.erase(I);
+  return MBB.erase(I);
 }
 
 void XCoreFrameLowering::determineCalleeSaves(MachineFunction &MF,
diff --git a/llvm/lib/Target/XCore/XCoreFrameLowering.h b/llvm/lib/Target/XCore/XCoreFrameLowering.h
index 69c71adc8d3..8729d2208bb 100644
--- a/llvm/lib/Target/XCore/XCoreFrameLowering.h
+++ b/llvm/lib/Target/XCore/XCoreFrameLowering.h
@@ -41,8 +41,8 @@ namespace llvm {
                                   const std::vector<CalleeSavedInfo> &CSI,
                                   const TargetRegisterInfo *TRI) const override;
 
-    void eliminateCallFramePseudoInstr(MachineFunction &MF,
-                                  MachineBasicBlock &MBB,
+    MachineBasicBlock::iterator
+    eliminateCallFramePseudoInstr(MachineFunction &MF, MachineBasicBlock &MBB,
                                   MachineBasicBlock::iterator I) const override;
 
     bool hasFP(const MachineFunction &MF) const override;