[AVR] Use separate ProgMemWrapper for GlobalAddresses of constants

Author: gergoerdi

lib/Target/AVR/AVRISelLowering.cpp

@@ -236,6 +236,7 @@ const char *AVRTargetLowering::getTargetNodeName(unsigned Opcode) const {
     NODE(RETI_FLAG);
     NODE(CALL);
     NODE(WRAPPER);
+    NODE(PROGMEM_WRAPPER);
     NODE(LSL);
     NODE(LSR);
     NODE(ROL);
@@ -381,13 +382,20 @@ SDValue AVRTargetLowering::LowerGlobalAddress(SDValue Op,
                                               SelectionDAG &DAG) const {
   auto DL = DAG.getDataLayout();
 
-  const GlobalValue *GV = cast<GlobalAddressSDNode>(Op)->getGlobal();
+  const auto *GA = cast<GlobalAddressSDNode>(Op);
+  const GlobalValue *GV = GA->getGlobal();
+
+  unsigned Wrapper = AVRISD::WRAPPER;
+  if (const auto *GVar = dyn_cast<GlobalVariable>(GV))
+      if (GVar->isConstant())
+          Wrapper = AVRISD::PROGMEM_WRAPPER;
+
   int64_t Offset = cast<GlobalAddressSDNode>(Op)->getOffset();
 
   // Create the TargetGlobalAddress node, folding in the constant offset.
   SDValue Result =
       DAG.getTargetGlobalAddress(GV, SDLoc(Op), getPointerTy(DL), Offset);
-  return DAG.getNode(AVRISD::WRAPPER, SDLoc(Op), getPointerTy(DL), Result);
+  return DAG.getNode(Wrapper, SDLoc(Op), getPointerTy(DL), Result);
 }
 
 SDValue AVRTargetLowering::LowerBlockAddress(SDValue Op,

lib/Target/AVR/AVRISelLowering.h

@@ -36,6 +36,7 @@ enum NodeType {
   /// A wrapper node for TargetConstantPool,
   /// TargetExternalSymbol, and TargetGlobalAddress.
   WRAPPER,
+  PROGMEM_WRAPPER,
   LSL,     ///< Logical shift left.
   LSR,     ///< Logical shift right.
   ASR,     ///< Arithmetic shift right.

lib/Target/AVR/AVRInstrInfo.td

@@ -21,6 +21,7 @@ def SDT_AVRCallSeqStart : SDCallSeqStart<[SDTCisVT<0, i16>]>;
 def SDT_AVRCallSeqEnd : SDCallSeqEnd<[SDTCisVT<0, i16>, SDTCisVT<1, i16>]>;
 def SDT_AVRCall : SDTypeProfile<0, -1, [SDTCisVT<0, iPTR>]>;
 def SDT_AVRWrapper : SDTypeProfile<1, 1, [SDTCisSameAs<0, 1>, SDTCisPtrTy<0>]>;
+def SDT_AVRProgMemWrapper : SDTypeProfile<1, 1, [SDTCisSameAs<0, 1>, SDTCisPtrTy<0>]>;
 def SDT_AVRBrcond : SDTypeProfile<0, 2,
                                   [SDTCisVT<0, OtherVT>, SDTCisVT<1, i8>]>;
 def SDT_AVRCmp : SDTypeProfile<0, 2, [SDTCisSameAs<0, 1>]>;
@@ -46,6 +47,7 @@ def AVRcall : SDNode<"AVRISD::CALL", SDT_AVRCall,
                      [SDNPHasChain, SDNPOutGlue, SDNPOptInGlue, SDNPVariadic]>;
 
 def AVRWrapper : SDNode<"AVRISD::WRAPPER", SDT_AVRWrapper>;
+def AVRProgMemWrapper : SDNode<"AVRISD::PROGMEM_WRAPPER", SDT_AVRProgMemWrapper>;
 
 def AVRbrcond : SDNode<"AVRISD::BRCOND", SDT_AVRBrcond,
                        [SDNPHasChain, SDNPInGlue]>;
@@ -2033,9 +2035,9 @@ def Asr16 : ShiftPseudo<
 // Non-Instruction Patterns
 //===----------------------------------------------------------------------===//
 
-def : Pat<(i8 (load (add i16:$offset, (AVRWrapper tglobaladdr:$base)))),
+def : Pat<(i8 (load (add i16:$offset, (AVRProgMemWrapper tglobaladdr:$base)))),
           (LPMRdZ (SUBIWRdK i16:$offset, tglobaladdr:$base))>;
-def : Pat<(i16 (load (add i16:$offset, (AVRWrapper tglobaladdr:$base)))),
+def : Pat<(i16 (load (add i16:$offset, (AVRProgMemWrapper tglobaladdr:$base)))),
           (LPMWRdZ (SUBIWRdK i16:$offset, tglobaladdr:$base))>;
 
 //:TODO: look in x86InstrCompiler.td for odd encoding trick related to