[PowerPC] Move the stack pointer update instruction later in the prologue and earlier in the epilogue.

Move the stdu instruction in the prologue and epilogue.
This should provide a small performance boost in functions that are able to do
this. I've kept this change rather conservative at the moment and functions
with frame pointers or base pointers will not try to move the stack pointer
update.

Differential Revision: https://reviews.llvm.org/D42590

llvm-svn: 355085

1 files changed, 1 insertions, 3 deletions

diff --git a/llvm/lib/Target/PowerPC/PPCRegisterInfo.h b/llvm/lib/Target/PowerPC/PPCRegisterInfo.h
index 7aae153facf..9e11bef87e5 100644
--- a/llvm/lib/Target/PowerPC/PPCRegisterInfo.h
+++ b/llvm/lib/Target/PowerPC/PPCRegisterInfo.h
@@ -89,9 +89,7 @@ public:
     return true;
   }
 
-  bool requiresFrameIndexScavenging(const MachineFunction &MF) const override {
-    return true;
-  }
+  bool requiresFrameIndexScavenging(const MachineFunction &MF) const override;
 
   bool trackLivenessAfterRegAlloc(const MachineFunction &MF) const override {
     return true;