From 1fde65ece2163c459069a8f3a42bd2663994c88c Mon Sep 17 00:00:00 2001
From: Santiago Aboy Solanes <solanes@google.com>
Date: Mon, 13 Nov 2023 16:40:52 +0000
Subject: Constant fold Reverse/ReverseBytes

Bug: 309886589
Test: art/test/testrunner/testrunner.py --host --64 -b --optimizing
Change-Id: Ibdf60f579b44b5d2609e0e89b98a41dd0a8b7a89
---
 compiler/optimizing/constant_folding.cc | 59 +++++++++++++++++++++++++++++++++
 1 file changed, 59 insertions(+)

(limited to 'compiler/optimizing/constant_folding.cc')

diff --git a/compiler/optimizing/constant_folding.cc b/compiler/optimizing/constant_folding.cc
index 686ecf08d2..e2bfffb8ec 100644
--- a/compiler/optimizing/constant_folding.cc
+++ b/compiler/optimizing/constant_folding.cc
@@ -19,6 +19,7 @@
 #include <algorithm>
 
 #include "base/bit_utils.h"
+#include "base/casts.h"
 #include "base/logging.h"
 #include "dex/dex_file-inl.h"
 #include "intrinsics_enum.h"
@@ -56,6 +57,8 @@ class HConstantFoldingVisitor final : public HGraphDelegateVisitor {
   void PropagateValue(HBasicBlock* starting_block, HInstruction* variable, HConstant* constant);
 
   // Intrinsics foldings
+  void FoldReverseIntrinsic(HInvoke* invoke);
+  void FoldReverseBytesIntrinsic(HInvoke* invoke);
   void FoldHighestOneBitIntrinsic(HInvoke* invoke);
   void FoldLowestOneBitIntrinsic(HInvoke* invoke);
   void FoldNumberOfLeadingZerosIntrinsic(HInvoke* invoke);
@@ -362,6 +365,15 @@ void HConstantFoldingVisitor::VisitIf(HIf* inst) {
 
 void HConstantFoldingVisitor::VisitInvoke(HInvoke* inst) {
   switch (inst->GetIntrinsic()) {
+    case Intrinsics::kIntegerReverse:
+    case Intrinsics::kLongReverse:
+      FoldReverseIntrinsic(inst);
+      break;
+    case Intrinsics::kIntegerReverseBytes:
+    case Intrinsics::kLongReverseBytes:
+    case Intrinsics::kShortReverseBytes:
+      FoldReverseBytesIntrinsic(inst);
+      break;
     case Intrinsics::kIntegerHighestOneBit:
     case Intrinsics::kLongHighestOneBit:
       FoldHighestOneBitIntrinsic(inst);
@@ -383,6 +395,53 @@ void HConstantFoldingVisitor::VisitInvoke(HInvoke* inst) {
   }
 }
 
+void HConstantFoldingVisitor::FoldReverseIntrinsic(HInvoke* inst) {
+  DCHECK(inst->GetIntrinsic() == Intrinsics::kIntegerReverse ||
+         inst->GetIntrinsic() == Intrinsics::kLongReverse);
+
+  HInstruction* input = inst->InputAt(0);
+  if (!input->IsConstant()) {
+    return;
+  }
+
+  // Integer and Long intrinsics have different return types.
+  if (inst->GetIntrinsic() == Intrinsics::kIntegerReverse) {
+    DCHECK(input->IsIntConstant());
+    inst->ReplaceWith(
+        GetGraph()->GetIntConstant(ReverseBits32(input->AsIntConstant()->GetValue())));
+  } else {
+    DCHECK(input->IsLongConstant());
+    inst->ReplaceWith(
+        GetGraph()->GetLongConstant(ReverseBits64(input->AsLongConstant()->GetValue())));
+  }
+  inst->GetBlock()->RemoveInstruction(inst);
+}
+
+void HConstantFoldingVisitor::FoldReverseBytesIntrinsic(HInvoke* inst) {
+  DCHECK(inst->GetIntrinsic() == Intrinsics::kIntegerReverseBytes ||
+         inst->GetIntrinsic() == Intrinsics::kLongReverseBytes ||
+         inst->GetIntrinsic() == Intrinsics::kShortReverseBytes);
+
+  HInstruction* input = inst->InputAt(0);
+  if (!input->IsConstant()) {
+    return;
+  }
+
+  // Integer, Long, and Short intrinsics have different return types.
+  if (inst->GetIntrinsic() == Intrinsics::kIntegerReverseBytes) {
+    DCHECK(input->IsIntConstant());
+    inst->ReplaceWith(GetGraph()->GetIntConstant(BSWAP(input->AsIntConstant()->GetValue())));
+  } else if (inst->GetIntrinsic() == Intrinsics::kLongReverseBytes) {
+    DCHECK(input->IsLongConstant());
+    inst->ReplaceWith(GetGraph()->GetLongConstant(BSWAP(input->AsLongConstant()->GetValue())));
+  } else {
+    DCHECK(input->IsIntConstant());
+    inst->ReplaceWith(GetGraph()->GetIntConstant(
+        BSWAP(dchecked_integral_cast<int16_t>(input->AsIntConstant()->GetValue()))));
+  }
+  inst->GetBlock()->RemoveInstruction(inst);
+}
+
 void HConstantFoldingVisitor::FoldHighestOneBitIntrinsic(HInvoke* inst) {
   DCHECK(inst->GetIntrinsic() == Intrinsics::kIntegerHighestOneBit ||
          inst->GetIntrinsic() == Intrinsics::kLongHighestOneBit);
-- 
cgit v1.2.3-59-g8ed1b