Implement new way of expanding extloads.

Now that the source and destination types can be specified,
allow doing an expansion that doesn't use an EXTLOAD of the
result type. Try to do a legal extload to an intermediate type
and extend that if possible.

This generalizes the special case custom lowering of extloads
R600 has been using to work around this problem.

This also happens to fix a bug that would incorrectly use more
aligned loads than should be used.

llvm-svn: 225925

1 files changed, 8 insertions, 18 deletions

diff --git a/llvm/lib/Target/R600/AMDGPUISelLowering.cpp b/llvm/lib/Target/R600/AMDGPUISelLowering.cpp
index 1ad2a693da1..206050d54a0 100644
--- a/llvm/lib/Target/R600/AMDGPUISelLowering.cpp
+++ b/llvm/lib/Target/R600/AMDGPUISelLowering.cpp
@@ -216,6 +216,14 @@ AMDGPUTargetLowering::AMDGPUTargetLowering(TargetMachine &TM) :
   setOperationAction(ISD::EXTRACT_SUBVECTOR, MVT::v8f32, Custom);
   setOperationAction(ISD::EXTRACT_SUBVECTOR, MVT::v8i32, Custom);
 
+  // There are no 64-bit extloads. These should be done as a 32-bit extload and
+  // an extension to 64-bit.
+  for (MVT VT : MVT::integer_valuetypes()) {
+    setLoadExtAction(ISD::EXTLOAD, MVT::i64, VT, Expand);
+    setLoadExtAction(ISD::SEXTLOAD, MVT::i64, VT, Expand);
+    setLoadExtAction(ISD::ZEXTLOAD, MVT::i64, VT, Expand);
+  }
+
   for (MVT VT : MVT::integer_vector_valuetypes()) {
     setLoadExtAction(ISD::EXTLOAD, VT, MVT::v2i8, Expand);
     setLoadExtAction(ISD::SEXTLOAD, VT, MVT::v2i8, Expand);
@@ -1412,24 +1420,6 @@ SDValue AMDGPUTargetLowering::LowerLOAD(SDValue Op, SelectionDAG &DAG) const {
   EVT VT = Op.getValueType();
   EVT MemVT = Load->getMemoryVT();
 
-  if (ExtType != ISD::NON_EXTLOAD && !VT.isVector() && VT.getSizeInBits() > 32) {
-    // We can do the extload to 32-bits, and then need to separately extend to
-    // 64-bits.
-
-    SDValue ExtLoad32 = DAG.getExtLoad(ExtType, DL, MVT::i32,
-                                       Load->getChain(),
-                                       Load->getBasePtr(),
-                                       MemVT,
-                                       Load->getMemOperand());
-
-    SDValue Ops[] = {
-      DAG.getNode(ISD::getExtForLoadExtType(ExtType), DL, VT, ExtLoad32),
-      ExtLoad32.getValue(1)
-    };
-
-    return DAG.getMergeValues(Ops, DL);
-  }
-
   if (ExtType == ISD::NON_EXTLOAD && VT.getSizeInBits() < 32) {
     assert(VT == MVT::i1 && "Only i1 non-extloads expected");
     // FIXME: Copied from PPC