[ARM GlobalISel] Support G_INTTOPTR and G_PTRTOINT for s32

Mark conversions between pointers and 32-bit scalars as legal, map them
to the GPR and select to a simple COPY.

llvm-svn: 321356

3 files changed, 30 insertions, 0 deletions

diff --git a/llvm/lib/Target/ARM/ARMInstructionSelector.cpp b/llvm/lib/Target/ARM/ARMInstructionSelector.cpp
index 2e8e7a7d967..b0fd0b47692 100644
--- a/llvm/lib/Target/ARM/ARMInstructionSelector.cpp
+++ b/llvm/lib/Target/ARM/ARMInstructionSelector.cpp
@@ -788,6 +788,28 @@ bool ARMInstructionSelector::select(MachineInstr &I,
     I.setDesc(TII.get(COPY));
     return selectCopy(I, TII, MRI, TRI, RBI);
   }
+  case G_INTTOPTR:
+  case G_PTRTOINT: {
+    auto SrcReg = I.getOperand(1).getReg();
+    auto DstReg = I.getOperand(0).getReg();
+
+    const auto &SrcRegBank = *RBI.getRegBank(SrcReg, MRI, TRI);
+    const auto &DstRegBank = *RBI.getRegBank(DstReg, MRI, TRI);
+
+    if (SrcRegBank.getID() != DstRegBank.getID()) {
+      DEBUG(dbgs()
+            << "G_INTTOPTR/G_PTRTOINT operands on different register banks\n");
+      return false;
+    }
+
+    if (SrcRegBank.getID() != ARM::GPRRegBankID) {
+      DEBUG(dbgs() << "G_INTTOPTR/G_PTRTOINT on non-GPR not supported yet\n");
+      return false;
+    }
+
+    I.setDesc(TII.get(COPY));
+    return selectCopy(I, TII, MRI, TRI, RBI);
+  }
   case G_SELECT:
     return selectSelect(MIB, MRI);
   case G_ICMP: {
diff --git a/llvm/lib/Target/ARM/ARMLegalizerInfo.cpp b/llvm/lib/Target/ARM/ARMLegalizerInfo.cpp
index d2095587a8b..8cff1f0869d 100644
--- a/llvm/lib/Target/ARM/ARMLegalizerInfo.cpp
+++ b/llvm/lib/Target/ARM/ARMLegalizerInfo.cpp
@@ -126,6 +126,12 @@ ARMLegalizerInfo::ARMLegalizerInfo(const ARMSubtarget &ST) {
     setAction({Op, s32}, Legal);
   }
 
+  setAction({G_INTTOPTR, p0}, Legal);
+  setAction({G_INTTOPTR, 1, s32}, Legal);
+
+  setAction({G_PTRTOINT, s32}, Legal);
+  setAction({G_PTRTOINT, 1, p0}, Legal);
+
   for (unsigned Op : {G_ASHR, G_LSHR, G_SHL})
     setAction({Op, s32}, Legal);
 
diff --git a/llvm/lib/Target/ARM/ARMRegisterBankInfo.cpp b/llvm/lib/Target/ARM/ARMRegisterBankInfo.cpp
index 32d1d57d326..fad0e98285e 100644
--- a/llvm/lib/Target/ARM/ARMRegisterBankInfo.cpp
+++ b/llvm/lib/Target/ARM/ARMRegisterBankInfo.cpp
@@ -227,6 +227,8 @@ ARMRegisterBankInfo::getInstrMapping(const MachineInstr &MI) const {
   case G_ZEXT:
   case G_ANYEXT:
   case G_GEP:
+  case G_INTTOPTR:
+  case G_PTRTOINT:
     // FIXME: We're abusing the fact that everything lives in a GPR for now; in
     // the real world we would use different mappings.
     OperandsMapping = &ARM::ValueMappings[ARM::GPR3OpsIdx];