From 17930b1810f80df34ff19d84cddc019f17cdf8e4 Mon Sep 17 00:00:00 2001
From: "chss95cs@gmail.com" <chss95cs@gmail.com>
Date: Sat, 3 Aug 2019 13:26:54 -0700
Subject: [PATCH] Add constant folding for OPCODE_ROTATE_LEFT

---
 .../passes/constant_propagation_pass.cc       |  9 +++++++-
 src/xenia/cpu/hir/value.cc                    | 23 +++++++++++++++++++
 src/xenia/cpu/hir/value.h                     |  1 +
 3 files changed, 32 insertions(+), 1 deletion(-)

diff --git a/src/xenia/cpu/compiler/passes/constant_propagation_pass.cc b/src/xenia/cpu/compiler/passes/constant_propagation_pass.cc
index b6b0376fa..acd1b5d64 100644
--- a/src/xenia/cpu/compiler/passes/constant_propagation_pass.cc
+++ b/src/xenia/cpu/compiler/passes/constant_propagation_pass.cc
@@ -712,7 +712,14 @@ bool ConstantPropagationPass::Run(HIRBuilder* builder, bool& result) {
             result = true;
           }
           break;
-        // TODO(benvanik): ROTATE_LEFT
+        case OPCODE_ROTATE_LEFT:
+          if (i->src1.value->IsConstant() && i->src2.value->IsConstant()) {
+            v->set_from(i->src1.value);
+            v->RotateLeft(i->src2.value);
+            i->Remove();
+            result = true;
+          }
+          break;
         case OPCODE_BYTE_SWAP:
           if (i->src1.value->IsConstant()) {
             v->set_from(i->src1.value);
diff --git a/src/xenia/cpu/hir/value.cc b/src/xenia/cpu/hir/value.cc
index 666648b03..eb487325e 100644
--- a/src/xenia/cpu/hir/value.cc
+++ b/src/xenia/cpu/hir/value.cc
@@ -843,6 +843,29 @@ void Value::Sha(Value* other) {
   }
 }
 
+void Value::RotateLeft(Value* other) {
+  assert_true(other->type == INT8_TYPE);
+  auto rotation = other->constant.u8;
+
+  switch (type) {
+    case INT8_TYPE:
+      constant.u8 = rotate_left<uint8_t>(constant.u8, rotation);
+      break;
+    case INT16_TYPE:
+      constant.u16 = rotate_left<uint16_t>(constant.u16, rotation);
+      break;
+    case INT32_TYPE:
+      constant.u32 = rotate_left<uint32_t>(constant.u32, rotation);
+      break;
+    case INT64_TYPE:
+      constant.u64 = rotate_left<uint64_t>(constant.u64, rotation);
+      break;
+    default:
+      assert_unhandled_case(type);
+      break;
+  }
+}
+
 void Value::Extract(Value* vec, Value* index) {
   assert_true(vec->type == VEC128_TYPE);
   switch (type) {
diff --git a/src/xenia/cpu/hir/value.h b/src/xenia/cpu/hir/value.h
index dcc95ca8c..d2e0fbf6d 100644
--- a/src/xenia/cpu/hir/value.h
+++ b/src/xenia/cpu/hir/value.h
@@ -519,6 +519,7 @@ class Value {
   void Shl(Value* other);
   void Shr(Value* other);
   void Sha(Value* other);
+  void RotateLeft(Value* other);
   void Extract(Value* vec, Value* index);
   void Select(Value* other, Value* ctrl);
   void Splat(Value* other);