AMDGPU: Remove GCN features and predicates

These are no longer necessary since the R600 tablegen files are split
out now.

llvm-svn: 353548
diff --git a/llvm/lib/Target/AMDGPU/AMDGPUInstructions.td b/llvm/lib/Target/AMDGPU/AMDGPUInstructions.td
index c44c2fa..bdbfdaf 100644
--- a/llvm/lib/Target/AMDGPU/AMDGPUInstructions.td
+++ b/llvm/lib/Target/AMDGPU/AMDGPUInstructions.td
@@ -65,12 +65,8 @@
 
 def TruePredicate : Predicate<"true">;
 
-// Exists to help track down where SubtargetPredicate isn't set rather
-// than letting tablegen crash with an unhelpful error.
-def InvalidPred : Predicate<"predicate not set on instruction or pattern">;
-
 class PredicateControl {
-  Predicate SubtargetPredicate = InvalidPred;
+  Predicate SubtargetPredicate = TruePredicate;
   list<Predicate> AssemblerPredicates = [];
   Predicate AssemblerPredicate = TruePredicate;
   list<Predicate> OtherPredicates = [];
@@ -625,9 +621,7 @@
   : AMDGPUPat<
   (sub_type (extractelt vec_type:$src, sub_idx)),
   (EXTRACT_SUBREG $src, sub_reg)
-> {
-  let SubtargetPredicate = TruePredicate;
-}
+>;
 
 /* Insert element pattern */
 class Insert_Element <ValueType elem_type, ValueType vec_type,
@@ -635,9 +629,7 @@
   : AMDGPUPat <
   (insertelt vec_type:$vec, elem_type:$elem, sub_idx),
   (INSERT_SUBREG $vec, $elem, sub_reg)
-> {
-  let SubtargetPredicate = TruePredicate;
-}
+>;
 
 // XXX: Convert to new syntax and use COPY_TO_REG, once the DFAPacketizer
 // can handle COPY instructions.