AMDGPU: Disambiguate v3f16 format in load/store tables

Currently the searchable tables report the number of dwords. These
round to the same number for 3 and 4 component d16
instructions. Change this to report the number of elements so this
isn't ambiguous.

llvm-svn: 369202
diff --git a/llvm/lib/Target/AMDGPU/SILoadStoreOptimizer.cpp b/llvm/lib/Target/AMDGPU/SILoadStoreOptimizer.cpp
index 30ee082..70fb377 100644
--- a/llvm/lib/Target/AMDGPU/SILoadStoreOptimizer.cpp
+++ b/llvm/lib/Target/AMDGPU/SILoadStoreOptimizer.cpp
@@ -402,7 +402,8 @@
   const unsigned Opc = MI.getOpcode();
 
   if (TII->isMUBUF(MI)) {
-    return AMDGPU::getMUBUFDwords(Opc);
+    // FIXME: Handle d16 correctly
+    return AMDGPU::getMUBUFElements(Opc);
   }
 
   switch (Opc) {
@@ -977,6 +978,7 @@
 
   switch (CI.InstClass) {
   default:
+    // FIXME: Handle d16 correctly
     return AMDGPU::getMUBUFOpcode(CI.InstClass, Width);
   case UNKNOWN:
     llvm_unreachable("Unknown instruction class");