ART: Introduce Uint8 loads in compiled code.

Some vectorization patterns are not recognized anymore.
This shall be fixed later.

Test: m test-art-host-gtest
Test: testrunner.py --host --optimizing
Test: testrunner.py --target --optimizing on Nexus 5X
Test: Nexus 5X boots.
Bug: 23964345
Bug: 67935418
Change-Id: I587a328d4799529949c86fa8045c6df21e3a8617
diff --git a/compiler/optimizing/code_generator_x86.cc b/compiler/optimizing/code_generator_x86.cc
index 39a07b8..561be1b 100644
--- a/compiler/optimizing/code_generator_x86.cc
+++ b/compiler/optimizing/code_generator_x86.cc
@@ -4756,10 +4756,11 @@
   Register base = base_loc.AsRegister<Register>();
   Location out = locations->Out();
   bool is_volatile = field_info.IsVolatile();
-  DataType::Type field_type = field_info.GetFieldType();
+  DCHECK_EQ(DataType::Size(field_info.GetFieldType()), DataType::Size(instruction->GetType()));
+  DataType::Type load_type = instruction->GetType();
   uint32_t offset = field_info.GetFieldOffset().Uint32Value();
 
-  switch (field_type) {
+  switch (load_type) {
     case DataType::Type::kBool:
     case DataType::Type::kUint8: {
       __ movzxb(out.AsRegister<Register>(), Address(base, offset));
@@ -4837,11 +4838,11 @@
     }
 
     case DataType::Type::kVoid:
-      LOG(FATAL) << "Unreachable type " << field_type;
+      LOG(FATAL) << "Unreachable type " << load_type;
       UNREACHABLE();
   }
 
-  if (field_type == DataType::Type::kReference || field_type == DataType::Type::kInt64) {
+  if (load_type == DataType::Type::kReference || load_type == DataType::Type::kInt64) {
     // Potential implicit null checks, in the case of reference or
     // long fields, are handled in the previous switch statement.
   } else {
@@ -4849,7 +4850,7 @@
   }
 
   if (is_volatile) {
-    if (field_type == DataType::Type::kReference) {
+    if (load_type == DataType::Type::kReference) {
       // Memory barriers, in the case of references, are also handled
       // in the previous switch statement.
     } else {