Re-commit: [globalisel] Add a combiner helpers for extending loads and use them in a pre-legalize combiner for AArch64

Summary: Depends on D45541

Reviewers: ab, aditya_nandakumar, bogner, rtereshin, volkan, rovka, javed.absar, aemerson

Subscribers: aemerson, rengolin, mgorny, javed.absar, kristof.beyls, llvm-commits

Differential Revision: https://reviews.llvm.org/D45543

The previous commit failed portions of the test-suite on GreenDragon due to
duplicate COPY instructions and iterator invalidation. Both issues have now
been fixed. To assist with this, a helper (cloneVirtualRegister) has been added
to MachineRegisterInfo that can be used to get another register that has the same
type and class/bank as an existing one.

llvm-svn: 343654

1 files changed, 10 insertions, 0 deletions

diff --git a/llvm/lib/CodeGen/MachineRegisterInfo.cpp b/llvm/lib/CodeGen/MachineRegisterInfo.cpp
index f632a9bd457..1da99d91760 100644
--- a/llvm/lib/CodeGen/MachineRegisterInfo.cpp
+++ b/llvm/lib/CodeGen/MachineRegisterInfo.cpp
@@ -177,6 +177,16 @@ MachineRegisterInfo::createVirtualRegister(const TargetRegisterClass *RegClass,
   return Reg;
 }
 
+unsigned MachineRegisterInfo::cloneVirtualRegister(unsigned VReg,
+                                                   StringRef Name) {
+  unsigned Reg = createIncompleteVirtualRegister(Name);
+  VRegInfo[Reg].first = VRegInfo[VReg].first;
+  setType(Reg, getType(VReg));
+  if (TheDelegate)
+    TheDelegate->MRI_NoteNewVirtualRegister(Reg);
+  return Reg;
+}
+
 void MachineRegisterInfo::setType(unsigned VReg, LLT Ty) {
   // Check that VReg doesn't have a class.
   assert((getRegClassOrRegBank(VReg).isNull() ||