Pattern-match return.  Includes gross hack!


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@24874 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/PowerPC/PPCISelDAGToDAG.cpp b/lib/Target/PowerPC/PPCISelDAGToDAG.cpp
index 338be66..4d9abdc 100644
--- a/lib/Target/PowerPC/PPCISelDAGToDAG.cpp
+++ b/lib/Target/PowerPC/PPCISelDAGToDAG.cpp
@@ -1043,29 +1043,6 @@
                                 Select(N->getOperand(3)),
                                 getI32Imm(BROpc));
   }
-    
-  case ISD::RET: {
-    SDOperand Chain = Select(N->getOperand(0));     // Token chain.
-
-    if (N->getNumOperands() == 2) {
-      SDOperand Val = Select(N->getOperand(1));
-      if (N->getOperand(1).getValueType() == MVT::i32) {
-        Chain = CurDAG->getCopyToReg(Chain, PPC::R3, Val);
-      } else {
-        assert(MVT::isFloatingPoint(N->getOperand(1).getValueType()));
-        Chain = CurDAG->getCopyToReg(Chain, PPC::F1, Val);
-      }
-    } else if (N->getNumOperands() > 1) {
-      assert(N->getOperand(1).getValueType() == MVT::i32 &&
-             N->getOperand(2).getValueType() == MVT::i32 &&
-             N->getNumOperands() == 3 && "Unknown two-register ret value!");
-      Chain = CurDAG->getCopyToReg(Chain, PPC::R4, Select(N->getOperand(1)));
-      Chain = CurDAG->getCopyToReg(Chain, PPC::R3, Select(N->getOperand(2)));
-    }
-
-    // Finally, select this to a blr (return) instruction.
-    return CurDAG->SelectNodeTo(N, PPC::BLR, MVT::Other, Chain);
-  }
   case ISD::BR_CC:
   case ISD::BRTWOWAY_CC: {
     SDOperand Chain = Select(N->getOperand(0));
diff --git a/lib/Target/PowerPC/PPCISelLowering.cpp b/lib/Target/PowerPC/PPCISelLowering.cpp
index ba3fa0e..0e5000e 100644
--- a/lib/Target/PowerPC/PPCISelLowering.cpp
+++ b/lib/Target/PowerPC/PPCISelLowering.cpp
@@ -793,15 +793,26 @@
 
 SDOperand PPCTargetLowering::LowerReturnTo(SDOperand Chain, SDOperand Op,
                                            SelectionDAG &DAG) {
-  if (Op.getValueType() == MVT::i64) {
-    SDOperand Hi = DAG.getNode(ISD::EXTRACT_ELEMENT, MVT::i32, Op, 
-                               DAG.getConstant(1, MVT::i32));
-    SDOperand Lo = DAG.getNode(ISD::EXTRACT_ELEMENT, MVT::i32, Op,
-                               DAG.getConstant(0, MVT::i32));
-    return DAG.getNode(ISD::RET, MVT::Other, Chain, Lo, Hi);
-  } else {
-    return DAG.getNode(ISD::RET, MVT::Other, Chain, Op);
+  SDOperand Copy;
+  switch (Op.getValueType()) {
+    default: assert(0 && "Unknown type to return!");
+    case MVT::i32:
+      Copy = DAG.getCopyToReg(Chain, PPC::R3, Op, SDOperand());
+      break;
+    case MVT::f32:
+    case MVT::f64:
+      Copy = DAG.getCopyToReg(Chain, PPC::F1, Op, SDOperand());
+      break;
+    case MVT::i64:
+      SDOperand Hi = DAG.getNode(ISD::EXTRACT_ELEMENT, MVT::i32, Op, 
+                                 DAG.getConstant(1, MVT::i32));
+      SDOperand Lo = DAG.getNode(ISD::EXTRACT_ELEMENT, MVT::i32, Op,
+                                 DAG.getConstant(0, MVT::i32));
+      Copy = DAG.getCopyToReg(Chain, PPC::R3, Hi, SDOperand());
+      Copy = DAG.getCopyToReg(Copy, PPC::R4, Lo, Copy.getValue(1));
+      break;
   }
+  return DAG.getNode(PPCISD::RET_FLAG, MVT::Other, Copy, Copy.getValue(1));
 }
 
 SDOperand PPCTargetLowering::LowerVAStart(SDOperand Chain, SDOperand VAListP,
diff --git a/lib/Target/PowerPC/PPCISelLowering.h b/lib/Target/PowerPC/PPCISelLowering.h
index 4cce315..daf392c 100644
--- a/lib/Target/PowerPC/PPCISelLowering.h
+++ b/lib/Target/PowerPC/PPCISelLowering.h
@@ -54,12 +54,14 @@
       /// at function entry, used for PIC code.
       GlobalBaseReg,
       
-      
       /// These nodes represent the 32-bit PPC shifts that operate on 6-bit
       /// shift amounts.  These nodes are generated by the multi-precision shift
       /// code.
       SRL, SRA, SHL,
-    };
+
+      /// Return with a flag operand, matched by 'blr'
+      RET_FLAG,
+};
   }  
   
   class PPCTargetLowering : public TargetLowering {
diff --git a/lib/Target/PowerPC/PPCInstrFormats.td b/lib/Target/PowerPC/PPCInstrFormats.td
index 8b28e5f..07f0e1c 100644
--- a/lib/Target/PowerPC/PPCInstrFormats.td
+++ b/lib/Target/PowerPC/PPCInstrFormats.td
@@ -328,12 +328,14 @@
 }
 
 class XLForm_2<bits<6> opcode, bits<10> xo, bit lk, dag OL, string asmstr, 
-               InstrItinClass itin>
+               InstrItinClass itin, list<dag> pattern>
     : I<opcode, OL, asmstr, itin> {
   bits<5> BO;
   bits<5> BI;
   bits<2> BH;
   
+  let Pattern = pattern;
+  
   let Inst{6-10}  = BO;
   let Inst{11-15} = BI;
   let Inst{16-18} = 0;
@@ -343,8 +345,8 @@
 }
 
 class XLForm_2_ext<bits<6> opcode, bits<10> xo, bits<5> bo,  bits<5> bi, bit lk,
-                  dag OL, string asmstr, InstrItinClass itin>
-  : XLForm_2<opcode, xo, lk, OL, asmstr, itin> {
+                  dag OL, string asmstr, InstrItinClass itin, list<dag> pattern>
+  : XLForm_2<opcode, xo, lk, OL, asmstr, itin, pattern> {
   let BO = bo;
   let BI = bi;
   let BH = 0;
diff --git a/lib/Target/PowerPC/PPCInstrInfo.td b/lib/Target/PowerPC/PPCInstrInfo.td
index 12a6cfb..a0356a6 100644
--- a/lib/Target/PowerPC/PPCInstrInfo.td
+++ b/lib/Target/PowerPC/PPCInstrInfo.td
@@ -46,6 +46,9 @@
 def callseq_start : SDNode<"ISD::CALLSEQ_START", SDT_PPCCallSeq,[SDNPHasChain]>;
 def callseq_end   : SDNode<"ISD::CALLSEQ_END",   SDT_PPCCallSeq,[SDNPHasChain]>;
 
+def SDT_PPCRetFlag : SDTypeProfile<0, 1, [ SDTCisVT<0, FlagVT>]>;
+def retflag       : SDNode<"PPCISD::RET_FLAG", SDT_PPCRetFlag, [SDNPHasChain]>;
+
 //===----------------------------------------------------------------------===//
 // PowerPC specific transformation functions and pattern fragments.
 //
@@ -221,8 +224,8 @@
 
 let isTerminator = 1 in {
   let isReturn = 1 in
-    def BLR : XLForm_2_ext<19, 16, 20, 0, 0, (ops), "blr", BrB>;
-  def BCTR : XLForm_2_ext<19, 528, 20, 0, 0, (ops), "bctr", BrB>;
+    def BLR : XLForm_2_ext<19, 16, 20, 0, 0, (ops), "blr", BrB, [(ret)]>;
+  def BCTR : XLForm_2_ext<19, 528, 20, 0, 0, (ops), "bctr", BrB, []>;
 }
 
 let Defs = [LR] in
@@ -267,7 +270,8 @@
                             "bl $func", BrB, []>;
   def BLA : IForm<18, 1, 1, (ops aaddr:$func, variable_ops),
                             "bla $func", BrB, []>;
-  def BCTRL : XLForm_2_ext<19, 528, 20, 0, 1, (ops variable_ops), "bctrl", BrB>;
+  def BCTRL : XLForm_2_ext<19, 528, 20, 0, 1, (ops variable_ops), "bctrl", BrB,
+                           []>;
 }
 
 // D-Form instructions.  Most instructions that perform an operation on a
@@ -1052,6 +1056,8 @@
 def : Pat<(f64 (extload xaddr:$src, f32)),
           (FMRSD (LFSX xaddr:$src))>;
 
+def : Pat<(retflag FLAG), (BLR)>;
+
 // Same as above, but using a temporary. FIXME: implement temporaries :)
 /*
 def : Pattern<(xor GPRC:$in, imm:$imm),
diff --git a/lib/Target/PowerPC/PPCRegisterInfo.td b/lib/Target/PowerPC/PPCRegisterInfo.td
index f349500..c8ac374 100644
--- a/lib/Target/PowerPC/PPCRegisterInfo.td
+++ b/lib/Target/PowerPC/PPCRegisterInfo.td
@@ -132,6 +132,14 @@
 // VRsave register
 def VRSAVE: SPR<256, "VRsave">;
 
+// FIXME:
+// HACKTROCITY: define a flags reg class for things that need to take a flag.
+// this should really be handled by tablgen.
+def FLAG: SPR<1023, "Flag">;
+def FLAGRC : RegisterClass<"PPC", [FlagVT], 32, [FLAG]> {
+  let Size = 32;
+}
+
 /// Register classes
 // Allocate volatiles first
 // then nonvolatiles in reverse order since stmw/lmw save from rN to r31