Introduce EVT::getHalfSizedIntegerVT() for use in ExpandUnalignedStore() in

LegalizeDAG.cpp. Unlike the code it replaces, which simply decrements the simple
type by one, getHalfSizedIntegerVT() searches for the smallest simple integer
type that is at least half the size of the type it is called on. This approach
has the advantage that it will continue working if a new value type (such as
i24) is added to MVT.

Also, in preparation for new value types, remove the assertions that
non-power-of-2 8-bit-mutiple types are Extended when legalizing extload and
truncstore operations.

llvm-svn: 91614

1 files changed, 3 insertions, 6 deletions

diff --git a/llvm/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp b/llvm/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp
index f9c05d081da..300e6eba139 100644
--- a/llvm/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp
@@ -461,8 +461,7 @@ SDValue ExpandUnalignedStore(StoreSDNode *ST, SelectionDAG &DAG,
          !ST->getMemoryVT().isVector() &&
          "Unaligned store of unknown type.");
   // Get the half-size VT
-  EVT NewStoredVT =
-    (MVT::SimpleValueType)(ST->getMemoryVT().getSimpleVT().SimpleTy - 1);
+  EVT NewStoredVT = ST->getMemoryVT().getHalfSizedIntegerVT(*DAG.getContext());
   int NumBits = NewStoredVT.getSizeInBits();
   int IncrementSize = NumBits / 8;
 
@@ -1170,8 +1169,7 @@ SDValue SelectionDAGLegalize::LegalizeOp(SDValue Op) {
         Tmp2 = LegalizeOp(Ch);
       } else if (SrcWidth & (SrcWidth - 1)) {
         // If not loading a power-of-2 number of bits, expand as two loads.
-        assert(SrcVT.isExtended() && !SrcVT.isVector() &&
-               "Unsupported extload!");
+        assert(!SrcVT.isVector() && "Unsupported extload!");
         unsigned RoundWidth = 1 << Log2_32(SrcWidth);
         assert(RoundWidth < SrcWidth);
         unsigned ExtraWidth = SrcWidth - RoundWidth;
@@ -1384,8 +1382,7 @@ SDValue SelectionDAGLegalize::LegalizeOp(SDValue Op) {
                                    SVOffset, NVT, isVolatile, Alignment);
       } else if (StWidth & (StWidth - 1)) {
         // If not storing a power-of-2 number of bits, expand as two stores.
-        assert(StVT.isExtended() && !StVT.isVector() &&
-               "Unsupported truncstore!");
+        assert(!StVT.isVector() && "Unsupported truncstore!");
         unsigned RoundWidth = 1 << Log2_32(StWidth);
         assert(RoundWidth < StWidth);
         unsigned ExtraWidth = StWidth - RoundWidth;