Refactor the type legalizer. Switch TargetLowering to a new enum - LegalizeTypeAction.

This patch does not change the behavior of the type legalizer. The codegen
produces the same code.
This infrastructural change is needed in order to enable complex decisions
for vector types (needed by the vector-select patch).




git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@132263 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 36 insertions, 20 deletions

diff --git a/include/llvm/Target/TargetLowering.h b/include/llvm/Target/TargetLowering.h
index 4ed52e6e84..3093ddfc29 100644
--- a/include/llvm/Target/TargetLowering.h
+++ b/include/llvm/Target/TargetLowering.h
@@ -94,6 +94,19 @@ public:
     Custom      // Use the LowerOperation hook to implement custom lowering.
   };
 
+  /// LegalizeAction - This enum indicates whether a types are legal for a
+  /// target, and if not, what action should be used to make them valid.
+  enum LegalizeTypeAction {
+    TypeLegal,           // The target natively supports this type.
+    TypePromoteInteger,  // Replace this integer with a larger one.
+    TypeExpandInteger,   // Split this integer into two of half the size.
+    TypeSoftenFloat,     // Convert this float to a same size integer type.
+    TypeExpandFloat,     // Split this float into two of half the size.
+    TypeScalarizeVector, // Replace this one-element vector with its element.
+    TypeSplitVector,     // Split this vector into two of half the size.
+    TypeWidenVector      // This vector should be widened into a larger vector.
+  };
+
   enum BooleanContent { // How the target represents true/false values.
     UndefinedBooleanContent,    // Only bit 0 counts, the rest can hold garbage.
     ZeroOrOneBooleanContent,        // All bits zero except for bit 0.
@@ -200,7 +213,7 @@ public:
   }
 
   class ValueTypeActionImpl {
-    /// ValueTypeActions - For each value type, keep a LegalizeAction enum
+    /// ValueTypeActions - For each value type, keep a LegalizeTypeAction enum
     /// that indicates how instruction selection should deal with the type.
     uint8_t ValueTypeActions[MVT::LAST_VALUETYPE];
 
@@ -209,11 +222,11 @@ public:
       std::fill(ValueTypeActions, array_endof(ValueTypeActions), 0);
     }
 
-    LegalizeAction getTypeAction(MVT VT) const {
-      return (LegalizeAction)ValueTypeActions[VT.SimpleTy];
+    LegalizeTypeAction getTypeAction(MVT VT) const {
+      return (LegalizeTypeAction)ValueTypeActions[VT.SimpleTy];
     }
 
-    void setTypeAction(EVT VT, LegalizeAction Action) {
+    void setTypeAction(EVT VT, LegalizeTypeAction Action) {
       unsigned I = VT.getSimpleVT().SimpleTy;
       ValueTypeActions[I] = Action;
     }
@@ -227,10 +240,10 @@ public:
   /// it is already legal (return 'Legal') or we need to promote it to a larger
   /// type (return 'Promote'), or we need to expand it into multiple registers
   /// of smaller integer type (return 'Expand').  'Custom' is not an option.
-  LegalizeAction getTypeAction(LLVMContext &Context, EVT VT) const {
+  LegalizeTypeAction getTypeAction(LLVMContext &Context, EVT VT) const {
     return getTypeConversion(Context, VT).first;
   }
-  LegalizeAction getTypeAction(MVT VT) const {
+  LegalizeTypeAction getTypeAction(MVT VT) const {
     return ValueTypeActions.getTypeAction(VT);
   }
 
@@ -1732,7 +1745,7 @@ private:
 
   ValueTypeActionImpl ValueTypeActions;
 
-  typedef std::pair<LegalizeAction, EVT> LegalizeKind;
+  typedef std::pair<LegalizeTypeAction, EVT> LegalizeKind;
 
   LegalizeKind
   getTypeConversion(LLVMContext &Context, EVT VT) const {
@@ -1741,10 +1754,13 @@ private:
       assert((unsigned)VT.getSimpleVT().SimpleTy <
              array_lengthof(TransformToType));
       EVT NVT = TransformToType[VT.getSimpleVT().SimpleTy];
-      LegalizeAction LA = ValueTypeActions.getTypeAction(VT.getSimpleVT());
-      if (NVT.isSimple() && LA != Legal)
-        assert(ValueTypeActions.getTypeAction(NVT.getSimpleVT()) != Promote &&
-               "Promote may not follow Expand or Promote");
+      LegalizeTypeAction LA = ValueTypeActions.getTypeAction(VT.getSimpleVT());
+
+      assert((NVT.isSimple() && LA != TypeLegal )? 
+             ValueTypeActions.getTypeAction(
+               NVT.getSimpleVT()) != TypePromoteInteger
+              : 1 && "Promote may not follow Expand or Promote");
+
       return LegalizeKind(LA, NVT);
     }
 
@@ -1758,12 +1774,12 @@ private:
         assert(NVT != VT && "Unable to round integer VT");
         LegalizeKind NextStep = getTypeConversion(Context, NVT);
         // Avoid multi-step promotion.
-        if (NextStep.first == Promote) return NextStep;
+        if (NextStep.first == TypePromoteInteger) return NextStep;
         // Return rounded integer type.
-        return LegalizeKind(Promote, NVT);
+        return LegalizeKind(TypePromoteInteger, NVT);
       }
 
-      return LegalizeKind(Expand,
+      return LegalizeKind(TypeExpandInteger,
                           EVT::getIntegerVT(Context, VT.getSizeInBits()/2));
     }
 
@@ -1773,7 +1789,7 @@ private:
 
     // Vectors with only one element are always scalarized.
     if (NumElts == 1)
-      return LegalizeKind(Expand, EltVT);
+      return LegalizeKind(TypeScalarizeVector, EltVT);
 
     // Try to widen the vector until a legal type is found.
     // If there is no wider legal type, split the vector.
@@ -1788,22 +1804,22 @@ private:
       if (LargerVector == MVT()) break;
 
       // If this type is legal then widen the vector.
-      if (ValueTypeActions.getTypeAction(LargerVector) == Legal)
-        return LegalizeKind(Promote, LargerVector);
+      if (ValueTypeActions.getTypeAction(LargerVector) == TypeLegal)
+        return LegalizeKind(TypeWidenVector, LargerVector);
     }
 
     // Widen odd vectors to next power of two.
     if (!VT.isPow2VectorType()) {
       EVT NVT = VT.getPow2VectorType(Context);
-      return LegalizeKind(Promote, NVT);
+      return LegalizeKind(TypeWidenVector, NVT);
     }
 
     // Vectors with illegal element types are expanded.
     EVT NVT = EVT::getVectorVT(Context, EltVT, VT.getVectorNumElements() / 2);
-    return LegalizeKind(Expand, NVT);
+    return LegalizeKind(TypeSplitVector, NVT);
 
     assert(false && "Unable to handle this kind of vector type");
-    return LegalizeKind(Legal, VT);
+    return LegalizeKind(TypeLegal, VT);
   }
 
   std::vector<std::pair<EVT, TargetRegisterClass*> > AvailableRegClasses;