[GlobalISel][X86] G_ANYEXT support.

Summary: G_ANYEXT support

Reviewers: zvi, delena

Reviewed By: delena

Subscribers: rovka, kristof.beyls, llvm-commits

Differential Revision: https://reviews.llvm.org/D37675

llvm-svn: 312903

1 files changed, 55 insertions, 0 deletions

diff --git a/llvm/lib/Target/X86/X86InstructionSelector.cpp b/llvm/lib/Target/X86/X86InstructionSelector.cpp
index b43f88232bc..4ffcb92ed47 100644
--- a/llvm/lib/Target/X86/X86InstructionSelector.cpp
+++ b/llvm/lib/Target/X86/X86InstructionSelector.cpp
@@ -70,6 +70,8 @@ private:
                    MachineFunction &MF) const;
   bool selectZext(MachineInstr &I, MachineRegisterInfo &MRI,
                   MachineFunction &MF) const;
+  bool selectAnyext(MachineInstr &I, MachineRegisterInfo &MRI,
+                    MachineFunction &MF) const;
   bool selectCmp(MachineInstr &I, MachineRegisterInfo &MRI,
                  MachineFunction &MF) const;
   bool selectUadde(MachineInstr &I, MachineRegisterInfo &MRI,
@@ -318,6 +320,8 @@ bool X86InstructionSelector::select(MachineInstr &I) const {
     return true;
   if (selectZext(I, MRI, MF))
     return true;
+  if (selectAnyext(I, MRI, MF))
+    return true;
   if (selectCmp(I, MRI, MF))
     return true;
   if (selectUadde(I, MRI, MF))
@@ -720,6 +724,57 @@ bool X86InstructionSelector::selectZext(MachineInstr &I,
   return true;
 }
 
+bool X86InstructionSelector::selectAnyext(MachineInstr &I,
+                                          MachineRegisterInfo &MRI,
+                                          MachineFunction &MF) const {
+
+  if (I.getOpcode() != TargetOpcode::G_ANYEXT)
+    return false;
+
+  const unsigned DstReg = I.getOperand(0).getReg();
+  const unsigned SrcReg = I.getOperand(1).getReg();
+
+  const LLT DstTy = MRI.getType(DstReg);
+  const LLT SrcTy = MRI.getType(SrcReg);
+
+  const RegisterBank &DstRB = *RBI.getRegBank(DstReg, MRI, TRI);
+  const RegisterBank &SrcRB = *RBI.getRegBank(SrcReg, MRI, TRI);
+
+  assert (DstRB.getID() == SrcRB.getID() &&
+      "G_ANYEXT input/output on different banks\n");
+
+  assert (DstTy.getSizeInBits() > SrcTy.getSizeInBits() &&
+      "G_ANYEXT incorrect operand size");
+
+  if (DstRB.getID() != X86::GPRRegBankID)
+    return false;
+
+  const TargetRegisterClass *DstRC = getRegClass(DstTy, DstRB);
+  const TargetRegisterClass *SrcRC = getRegClass(SrcTy, SrcRB);
+
+  if (!RBI.constrainGenericRegister(SrcReg, *SrcRC, MRI) ||
+      !RBI.constrainGenericRegister(DstReg, *DstRC, MRI)) {
+    DEBUG(dbgs() << "Failed to constrain " << TII.getName(I.getOpcode())
+                 << " operand\n");
+    return false;
+  }
+
+  if (SrcRC == DstRC) {
+    I.setDesc(TII.get(X86::COPY));
+    return true;
+  }
+
+  BuildMI(*I.getParent(), I, I.getDebugLoc(),
+          TII.get(TargetOpcode::SUBREG_TO_REG))
+      .addDef(DstReg)
+      .addImm(0)
+      .addReg(SrcReg)
+      .addImm(getSubRegIndex(SrcRC));
+
+  I.eraseFromParent();
+  return true;
+}
+
 bool X86InstructionSelector::selectCmp(MachineInstr &I,
                                        MachineRegisterInfo &MRI,
                                        MachineFunction &MF) const {