Optimizing: ARM64 negated bitwise operations simplification
Use negated instructions on ARM64 to replace [bitwise operation + not]
patterns, that is:
a & ~b (BIC)
a | ~b (ORN)
a ^ ~b (EON)
The simplification only happens if the Not is only used by the bitwise
operation. It does not happen if both inputs are Not's (this should be
handled by a generic simplification applying De Morgan's laws).
Change-Id: I0e112b23fd8b8e10f09bfeff5994508a8ff96e9c
diff --git a/compiler/optimizing/nodes_arm64.h b/compiler/optimizing/nodes_arm64.h
index 173852a..75a71e7 100644
--- a/compiler/optimizing/nodes_arm64.h
+++ b/compiler/optimizing/nodes_arm64.h
@@ -118,6 +118,66 @@
DISALLOW_COPY_AND_ASSIGN(HArm64IntermediateAddress);
};
+class HArm64BitwiseNegatedRight : public HBinaryOperation {
+ public:
+ HArm64BitwiseNegatedRight(Primitive::Type result_type,
+ InstructionKind op,
+ HInstruction* left,
+ HInstruction* right,
+ uint32_t dex_pc = kNoDexPc)
+ : HBinaryOperation(result_type, left, right, SideEffects::None(), dex_pc),
+ op_kind_(op) {
+ DCHECK(op == HInstruction::kAnd || op == HInstruction::kOr || op == HInstruction::kXor) << op;
+ }
+
+ template <typename T, typename U>
+ auto Compute(T x, U y) const -> decltype(x & ~y) {
+ static_assert(std::is_same<decltype(x & ~y), decltype(x | ~y)>::value &&
+ std::is_same<decltype(x & ~y), decltype(x ^ ~y)>::value,
+ "Inconsistent negated bitwise types");
+ switch (op_kind_) {
+ case HInstruction::kAnd:
+ return x & ~y;
+ case HInstruction::kOr:
+ return x | ~y;
+ case HInstruction::kXor:
+ return x ^ ~y;
+ default:
+ LOG(FATAL) << "Unreachable";
+ UNREACHABLE();
+ }
+ }
+
+ HConstant* Evaluate(HIntConstant* x, HIntConstant* y) const OVERRIDE {
+ return GetBlock()->GetGraph()->GetIntConstant(
+ Compute(x->GetValue(), y->GetValue()), GetDexPc());
+ }
+ HConstant* Evaluate(HLongConstant* x, HLongConstant* y) const OVERRIDE {
+ return GetBlock()->GetGraph()->GetLongConstant(
+ Compute(x->GetValue(), y->GetValue()), GetDexPc());
+ }
+ HConstant* Evaluate(HFloatConstant* x ATTRIBUTE_UNUSED,
+ HFloatConstant* y ATTRIBUTE_UNUSED) const OVERRIDE {
+ LOG(FATAL) << DebugName() << " is not defined for float values";
+ UNREACHABLE();
+ }
+ HConstant* Evaluate(HDoubleConstant* x ATTRIBUTE_UNUSED,
+ HDoubleConstant* y ATTRIBUTE_UNUSED) const OVERRIDE {
+ LOG(FATAL) << DebugName() << " is not defined for double values";
+ UNREACHABLE();
+ }
+
+ InstructionKind GetOpKind() const { return op_kind_; }
+
+ DECLARE_INSTRUCTION(Arm64BitwiseNegatedRight);
+
+ private:
+ // Specifies the bitwise operation, which will be then negated.
+ const InstructionKind op_kind_;
+
+ DISALLOW_COPY_AND_ASSIGN(HArm64BitwiseNegatedRight);
+};
+
} // namespace art
#endif // ART_COMPILER_OPTIMIZING_NODES_ARM64_H_