Move some information out of LegalizeDAG into the generic Target interface.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@19581 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm/Target/TargetLowering.h

@@ -53,7 +53,19 @@ class TargetLowering {
   /// each ValueType the target supports natively.
   TargetRegisterClass *RegClassForVT[MVT::LAST_VALUETYPE];
   unsigned char NumElementsForVT[MVT::LAST_VALUETYPE];
-  
+
+  /// ValueTypeActions - This is a bitvector that contains two bits for each
+  /// value type, where the two bits correspond to the LegalizeAction enum.
+  /// This can be queried with "getTypeAction(VT)".
+  unsigned ValueTypeActions;
+ 
+  /// TransformToType - For any value types we are promoting or expanding, this
+  /// contains the value type that we are changing to.  For Expanded types, this
+  /// contains one step of the expand (e.g. i64 -> i32), even if there are
+  /// multiple steps required (e.g. i64 -> i16).  For types natively supported
+  /// by the system, this holds the same type (e.g. i32 -> i32).
+  MVT::ValueType TransformToType[MVT::LAST_VALUETYPE];
+
   unsigned short UnsupportedOps[128];
   
   std::vector<double> LegalFPImmediates;
@@ -76,10 +88,30 @@ public:
     return RC;
   }
   
-  /// hasNativeSupportFor 
+  /// hasNativeSupportFor - Return true if the target has native support for the
+  /// specified value type.  This means that it has a register that directly
+  /// holds it without promotions or expansions.
   bool hasNativeSupportFor(MVT::ValueType VT) {
     return RegClassForVT[VT] != 0;
   }
+
+  /// getTypeAction - Return how we should legalize values of this type, either
+  /// it is already legal (return 0) or we need to promote it to a larger type
+  /// (return 1), or we need to expand it into multiple registers of smaller
+  /// integer type (return 2).
+  unsigned getTypeAction(MVT::ValueType VT) const {
+    return (ValueTypeActions >> (2*VT)) & 3;
+  }
+  unsigned getValueTypeActions() const { return ValueTypeActions; }
+
+  /// getTypeToTransformTo - For types supported by the target, this is an
+  /// identity function.  For types that must be promoted to larger types, this
+  /// returns the larger type to promote to.  For types that are larger than the
+  /// largest integer register, this contains one step in the expansion to get
+  /// to the smaller register.
+  MVT::ValueType getTypeToTransformTo(MVT::ValueType VT) {
+    return TransformToType[VT];
+  }
   
   typedef std::vector<double>::const_iterator legal_fpimm_iterator;
   legal_fpimm_iterator legal_fpimm_begin() const {

lib/CodeGen/SelectionDAG/TargetLowering.cpp

@@ -17,7 +17,7 @@
 using namespace llvm;
 
 TargetLowering::TargetLowering(TargetMachine &tm)
-  : TM(tm), TD(TM.getTargetData()) {
+  : TM(tm), TD(TM.getTargetData()), ValueTypeActions(0) {
   assert(ISD::BUILTIN_OP_END <= 128 &&
          "Fixed size array in TargetLowering is not large enough!");
 
@@ -27,9 +27,47 @@ TargetLowering::TargetLowering(TargetMachine &tm)
   memset(RegClassForVT, 0,MVT::LAST_VALUETYPE*sizeof(TargetRegisterClass*));
 }
 
+/// setValueTypeAction - Set the action for a particular value type.  This
+/// assumes an action has not already been set for this value type.
+static void SetValueTypeAction(MVT::ValueType VT, unsigned Action,
+                               TargetLowering &TLI,
+                               MVT::ValueType *TransformToType,
+                               unsigned &ValueTypeActions) {
+  ValueTypeActions |= Action << (VT*2);
+  if (Action == 1 /*promote*/) {
+    MVT::ValueType PromoteTo;
+    if (VT == MVT::f32)
+      PromoteTo = MVT::f64;
+    else {
+      unsigned LargerReg = VT+1;
+      while (!TLI.hasNativeSupportFor((MVT::ValueType)LargerReg)) {
+        ++LargerReg;
+        assert(MVT::isInteger((MVT::ValueType)LargerReg) &&
+               "Nothing to promote to??");
+      }
+      PromoteTo = (MVT::ValueType)LargerReg;
+    }
+
+    assert(MVT::isInteger(VT) == MVT::isInteger(PromoteTo) &&
+           MVT::isFloatingPoint(VT) == MVT::isFloatingPoint(PromoteTo) &&
+           "Can only promote from int->int or fp->fp!");
+    assert(VT < PromoteTo && "Must promote to a larger type!");
+    TransformToType[VT] = PromoteTo;
+  } else if (Action == 2) {
+    assert(MVT::isInteger(VT) && VT > MVT::i8 &&
+           "Cannot expand this type: target must support SOME integer reg!");
+    // Expand to the next smaller integer type!
+    TransformToType[VT] = (MVT::ValueType)(VT-1);
+  }
+}
+
+
 /// computeRegisterProperties - Once all of the register classes are added,
 /// this allows us to compute derived properties we expose.
 void TargetLowering::computeRegisterProperties() {
+  assert(MVT::LAST_VALUETYPE <= 16 &&
+         "Too many value types for ValueTypeActions to hold!");
+
   // Everything defaults to one.
   for (unsigned i = 0; i != MVT::LAST_VALUETYPE; ++i)
     NumElementsForVT[i] = 1;
@@ -44,5 +82,20 @@ void TargetLowering::computeRegisterProperties() {
   unsigned ExpandedReg = LargestIntReg; ++LargestIntReg;
   for (++ExpandedReg; MVT::isInteger((MVT::ValueType)ExpandedReg);++ExpandedReg)
     NumElementsForVT[ExpandedReg] = 2*NumElementsForVT[ExpandedReg-1];
-}
 
+  // Inspect all of the ValueType's possible, deciding how to process them.
+  for (unsigned IntReg = MVT::i1; IntReg <= MVT::i128; ++IntReg)
+    // If we are expanding this type, expand it!
+    if (getNumElements((MVT::ValueType)IntReg) != 1)
+      SetValueTypeAction((MVT::ValueType)IntReg, 2, *this, TransformToType,
+                         ValueTypeActions);
+    else if (!hasNativeSupportFor((MVT::ValueType)IntReg))
+      // Otherwise, if we don't have native support, we must promote to a
+      // larger type.
+      SetValueTypeAction((MVT::ValueType)IntReg, 1, *this, TransformToType,
+                         ValueTypeActions);
+  
+  // If the target does not have native support for F32, promote it to F64.
+  if (!hasNativeSupportFor(MVT::f32))
+    SetValueTypeAction(MVT::f32, 1, *this, TransformToType, ValueTypeActions);
+}