add an initial cut at preinc loads for ppc32. This is broken for ppc64

(because the 64-bit reg target versions aren't implemented yet), doesn't
support r+r addr modes, and doesn't handle stores, but it works otherwise. :)

This is disabled unless -enable-ppc-preinc is passed to llc for now.

llvm-svn: 31621

lib/Target/PowerPC/PPCISelDAGToDAG.cpp

@@ -818,6 +818,44 @@ SDNode *PPCDAGToDAGISel::Select(SDOperand Op) {
     // Other cases are autogenerated.
     break;
   }
+    
+  case ISD::LOAD: {
+    // Handle preincrement loads.
+    LoadSDNode *LD = cast<LoadSDNode>(Op);
+    MVT::ValueType LoadedVT = LD->getLoadedVT();
+    
+    // Normal loads are handled by code generated from the .td file.
+    if (LD->getAddressingMode() != ISD::PRE_INC)
+      break;
+    
+    unsigned Opcode;
+    bool isSExt = LD->getExtensionType() == ISD::SEXTLOAD;
+    assert(!isSExt || LoadedVT == MVT::i16 && "Invalid sext update load");
+    switch (LoadedVT) {
+    default: assert(0 && "Invalid PPC load type!");
+    case MVT::f64: Opcode = PPC::LFDU; break;
+    case MVT::f32: Opcode = PPC::LFSU; break;
+    case MVT::i32: Opcode = PPC::LWZU; break;
+    case MVT::i16: Opcode = isSExt ? PPC::LHAU : PPC::LHZU; break;
+    case MVT::i8:  Opcode = PPC::LBZU; break;
+    }
+    
+    SDOperand Offset = LD->getOffset();
+    if (isa<ConstantSDNode>(Offset)) {
+      SDOperand Chain = LD->getChain();
+      SDOperand Base = LD->getBasePtr();
+      AddToISelQueue(Chain);
+      AddToISelQueue(Base);
+      AddToISelQueue(Offset);
+      SDOperand Ops[] = { Offset, Base, Chain };
+      // FIXME: PPC64
+      return CurDAG->getTargetNode(Opcode, MVT::i32, MVT::i32,
+                                   MVT::Other, Ops, 3);
+    } else {
+      assert(0 && "R+R preindex loads not supported yet!");
+    }
+  }
+    
   case ISD::AND: {
     unsigned Imm, Imm2, SH, MB, ME;
 

lib/Target/PowerPC/PPCISelLowering.cpp

@@ -26,8 +26,11 @@
 #include "llvm/Intrinsics.h"
 #include "llvm/Support/MathExtras.h"
 #include "llvm/Target/TargetOptions.h"
+#include "llvm/Support/CommandLine.h"
 using namespace llvm;
 
+static cl::opt<bool> EnablePPCPreinc("enable-ppc-preinc");
+
 PPCTargetLowering::PPCTargetLowering(PPCTargetMachine &TM)
   : TargetLowering(TM), PPCSubTarget(*TM.getSubtargetImpl()) {
     
@@ -861,29 +864,27 @@ bool PPCTargetLowering::getPreIndexedAddressParts(SDNode *N, SDOperand &Base,
                                                   SDOperand &Offset,
                                                   ISD::MemIndexedMode &AM,
                                                   SelectionDAG &DAG) {
-  return false;
+  // Disabled by default for now.
+  if (!EnablePPCPreinc) return false;
   
-#if 0
-  MVT::ValueType VT;
   SDOperand Ptr;
   if (LoadSDNode *LD = dyn_cast<LoadSDNode>(N)) {
     Ptr = LD->getBasePtr();
-    VT  = LD->getLoadedVT();
-    
-    // TODO: handle other cases.
-    if (VT != MVT::i32) return false;
   } else if (StoreSDNode *ST = dyn_cast<StoreSDNode>(N)) {
-    Ptr = ST->getBasePtr();
-    VT  = ST->getStoredVT();
-    // TODO: handle other cases.
+    ST = ST;
+    //Ptr = ST->getBasePtr();
+    //VT  = ST->getStoredVT();
+    // TODO: handle stores.
     return false;
   } else
     return false;
 
+  // TODO: Handle reg+reg.
+  if (!SelectAddressRegImm(Ptr, Offset, Base, DAG))
+    return false;
   
-  
-  return false;
-#endif
+  AM = ISD::PRE_INC;
+  return true;
 }
 
 //===----------------------------------------------------------------------===//

lib/Target/PowerPC/PPCInstrInfo.td

@@ -422,9 +422,44 @@ def LWZ : DForm_1<32, (ops GPRC:$rD, memri:$src),
                   "lwz $rD, $src", LdStGeneral,
                   [(set GPRC:$rD, (load iaddr:$src))]>;
 
-def LWZU : DForm_1<33, (ops GPRC:$rD, GPRC:$rA_result, i32imm:$disp, GPRC:$rA),
+def LFS : DForm_8<48, (ops F4RC:$rD, memri:$src),
+                  "lfs $rD, $src", LdStLFDU,
+                  [(set F4RC:$rD, (load iaddr:$src))]>;
+def LFD : DForm_8<50, (ops F8RC:$rD, memri:$src),
+                  "lfd $rD, $src", LdStLFD,
+                  [(set F8RC:$rD, (load iaddr:$src))]>;
+
+// FIXME: PTRRC for Pointer regs for ppc64.
+
+// 'Update' load forms.
+def LBZU : DForm_1<35, (ops GPRC:$rD, ptr_rc:$rA_result, i32imm:$disp,
+                            ptr_rc:$rA),
+                   "lbzu $rD, $disp($rA)", LdStGeneral,
+                   []>, RegConstraint<"$rA = $rA_result">;
+
+def LHAU : DForm_1<43, (ops GPRC:$rD, ptr_rc:$rA_result, i32imm:$disp,
+                            ptr_rc:$rA),
+                   "lhau $rD, $disp($rA)", LdStGeneral,
+                   []>, RegConstraint<"$rA = $rA_result">;
+
+def LHZU : DForm_1<41, (ops GPRC:$rD, ptr_rc:$rA_result, i32imm:$disp,
+                            ptr_rc:$rA),
+                   "lhzu $rD, $disp($rA)", LdStGeneral,
+                   []>, RegConstraint<"$rA = $rA_result">;
+
+def LWZU : DForm_1<33, (ops GPRC:$rD, ptr_rc:$rA_result, i32imm:$disp,
+                            ptr_rc:$rA),
                    "lwzu $rD, $disp($rA)", LdStGeneral,
                    []>, RegConstraint<"$rA = $rA_result">;
+
+def LFSU : DForm_8<49, (ops F4RC:$rD, ptr_rc:$rA_result, i32imm:$disp,
+                            ptr_rc:$rA),
+                  "lfs $rD, $disp($rA)", LdStLFDU,
+                  []>, RegConstraint<"$rA = $rA_result">;
+def LFDU : DForm_8<51, (ops F8RC:$rD, ptr_rc:$rA_result, i32imm:$disp,
+                            ptr_rc:$rA),
+                  "lfd $rD, $disp($rA)", LdStLFD,
+                  []>, RegConstraint<"$rA = $rA_result">;
 }
 
 
@@ -501,14 +536,6 @@ def CMPWI : DForm_5_ext<11, (ops CRRC:$crD, GPRC:$rA, s16imm:$imm),
 def CMPLWI : DForm_6_ext<10, (ops CRRC:$dst, GPRC:$src1, u16imm:$src2),
                          "cmplwi $dst, $src1, $src2", IntCompare>;
 }
-let isLoad = 1, PPC970_Unit = 2 in {
-def LFS : DForm_8<48, (ops F4RC:$rD, memri:$src),
-                  "lfs $rD, $src", LdStLFDU,
-                  [(set F4RC:$rD, (load iaddr:$src))]>;
-def LFD : DForm_8<50, (ops F8RC:$rD, memri:$src),
-                  "lfd $rD, $src", LdStLFD,
-                  [(set F8RC:$rD, (load iaddr:$src))]>;
-}
 let isStore = 1, noResults = 1, PPC970_Unit = 2 in {
 def STFS : DForm_9<52, (ops F4RC:$rS, memri:$dst),
                    "stfs $rS, $dst", LdStUX,