[SystemZ] Use MVC to spill loads and stores
Try to use MVC when spilling the destination of a simple load or the source
of a simple store. As explained in the comment, this doesn't yet handle
the case where the load or store location is also a frame index, since
that could lead to two simultaneous scavenger spills, something the
backend can't handle yet. spill-02.py tests that this restriction kicks in,
but unfortunately I've not yet found a case that would fail without it.
The volatile trick I used for other scavenger tests doesn't work here
because we can't use MVC for volatile accesses anyway.
I'm planning on relaxing the restriction later, hopefully with a test
that does trigger the problem...
Tests @f8 and @f9 also showed that L(G)RL and ST(G)RL were wrongly
classified as SimpleBDX{Load,Store}. It wouldn't be easy to test for
that bug separately, which is why I didn't split out the fix as a
separate patch.
llvm-svn: 185434
diff --git a/llvm/lib/Target/SystemZ/SystemZInstrInfo.h b/llvm/lib/Target/SystemZ/SystemZInstrInfo.h
index d6980f7..8d9a3ea 100644
--- a/llvm/lib/Target/SystemZ/SystemZInstrInfo.h
+++ b/llvm/lib/Target/SystemZ/SystemZInstrInfo.h
@@ -111,6 +111,14 @@
unsigned DestReg, int FrameIdx,
const TargetRegisterClass *RC,
const TargetRegisterInfo *TRI) const LLVM_OVERRIDE;
+ virtual MachineInstr *
+ foldMemoryOperandImpl(MachineFunction &MF, MachineInstr *MI,
+ const SmallVectorImpl<unsigned> &Ops,
+ int FrameIndex) const;
+ virtual MachineInstr *
+ foldMemoryOperandImpl(MachineFunction &MF, MachineInstr* MI,
+ const SmallVectorImpl<unsigned> &Ops,
+ MachineInstr* LoadMI) const;
virtual bool
expandPostRAPseudo(MachineBasicBlock::iterator MBBI) const LLVM_OVERRIDE;
virtual bool