[optimizing] Fold HTypeConversion of constants
While looking into optimizing long shifts on x86, I found that the
compiler wasn't folding HTypeConversion of constants. Add simple
conversions of constants, taking care of float/double values
with NaNs and small/large values, ensuring Java conversion semantics.
Add checker cases to see that constant folding of HTypeConversion is
done.
Ensure 422-type-conversion type conversion routiness don't get
inlined to avoid compile time folding.
Change-Id: I5a4eb376b64bc4e41bf908af5875bed312efb228
Signed-off-by: Mark Mendell <mark.p.mendell@intel.com>
diff --git a/compiler/optimizing/code_generator.h b/compiler/optimizing/code_generator.h
index bdbd571..fcfedab 100644
--- a/compiler/optimizing/code_generator.h
+++ b/compiler/optimizing/code_generator.h
@@ -34,10 +34,15 @@
// Binary encoding of 2^31 for type double.
static int64_t constexpr k2Pow31EncodingForDouble = INT64_C(0x41E0000000000000);
+// Minimum value for a primitive integer.
+static int32_t constexpr kPrimIntMin = 0x80000000;
+// Minimum value for a primitive long.
+static int64_t constexpr kPrimLongMin = INT64_C(0x8000000000000000);
+
// Maximum value for a primitive integer.
static int32_t constexpr kPrimIntMax = 0x7fffffff;
// Maximum value for a primitive long.
-static int64_t constexpr kPrimLongMax = 0x7fffffffffffffff;
+static int64_t constexpr kPrimLongMax = INT64_C(0x7fffffffffffffff);
class Assembler;
class CodeGenerator;
diff --git a/compiler/optimizing/constant_folding.cc b/compiler/optimizing/constant_folding.cc
index 5a1d9b4..20ce110 100644
--- a/compiler/optimizing/constant_folding.cc
+++ b/compiler/optimizing/constant_folding.cc
@@ -71,6 +71,14 @@
inst->ReplaceWith(constant);
inst->GetBlock()->RemoveInstruction(inst);
}
+ } else if (inst->IsTypeConversion()) {
+ // Constant folding: replace `TypeConversion(a)' with a constant at
+ // compile time if `a' is a constant.
+ HConstant* constant = inst->AsTypeConversion()->TryStaticEvaluation();
+ if (constant != nullptr) {
+ inst->ReplaceWith(constant);
+ inst->GetBlock()->RemoveInstruction(inst);
+ }
} else if (inst->IsDivZeroCheck()) {
// We can safely remove the check if the input is a non-null constant.
HDivZeroCheck* check = inst->AsDivZeroCheck();
diff --git a/compiler/optimizing/nodes.cc b/compiler/optimizing/nodes.cc
index 41adc72..47da9cc 100644
--- a/compiler/optimizing/nodes.cc
+++ b/compiler/optimizing/nodes.cc
@@ -16,6 +16,7 @@
#include "nodes.h"
+#include "code_generator.h"
#include "ssa_builder.h"
#include "base/bit_vector-inl.h"
#include "utils/growable_array.h"
@@ -794,6 +795,84 @@
}
}
+HConstant* HTypeConversion::TryStaticEvaluation() const {
+ HGraph* graph = GetBlock()->GetGraph();
+ if (GetInput()->IsIntConstant()) {
+ int32_t value = GetInput()->AsIntConstant()->GetValue();
+ switch (GetResultType()) {
+ case Primitive::kPrimLong:
+ return graph->GetLongConstant(static_cast<int64_t>(value));
+ case Primitive::kPrimFloat:
+ return graph->GetFloatConstant(static_cast<float>(value));
+ case Primitive::kPrimDouble:
+ return graph->GetDoubleConstant(static_cast<double>(value));
+ default:
+ return nullptr;
+ }
+ } else if (GetInput()->IsLongConstant()) {
+ int64_t value = GetInput()->AsLongConstant()->GetValue();
+ switch (GetResultType()) {
+ case Primitive::kPrimInt:
+ return graph->GetIntConstant(static_cast<int32_t>(value));
+ case Primitive::kPrimFloat:
+ return graph->GetFloatConstant(static_cast<float>(value));
+ case Primitive::kPrimDouble:
+ return graph->GetDoubleConstant(static_cast<double>(value));
+ default:
+ return nullptr;
+ }
+ } else if (GetInput()->IsFloatConstant()) {
+ float value = GetInput()->AsFloatConstant()->GetValue();
+ switch (GetResultType()) {
+ case Primitive::kPrimInt:
+ if (std::isnan(value))
+ return graph->GetIntConstant(0);
+ if (value >= kPrimIntMax)
+ return graph->GetIntConstant(kPrimIntMax);
+ if (value <= kPrimIntMin)
+ return graph->GetIntConstant(kPrimIntMin);
+ return graph->GetIntConstant(static_cast<int32_t>(value));
+ case Primitive::kPrimLong:
+ if (std::isnan(value))
+ return graph->GetLongConstant(0);
+ if (value >= kPrimLongMax)
+ return graph->GetLongConstant(kPrimLongMax);
+ if (value <= kPrimLongMin)
+ return graph->GetLongConstant(kPrimLongMin);
+ return graph->GetLongConstant(static_cast<int64_t>(value));
+ case Primitive::kPrimDouble:
+ return graph->GetDoubleConstant(static_cast<double>(value));
+ default:
+ return nullptr;
+ }
+ } else if (GetInput()->IsDoubleConstant()) {
+ double value = GetInput()->AsDoubleConstant()->GetValue();
+ switch (GetResultType()) {
+ case Primitive::kPrimInt:
+ if (std::isnan(value))
+ return graph->GetIntConstant(0);
+ if (value >= kPrimIntMax)
+ return graph->GetIntConstant(kPrimIntMax);
+ if (value <= kPrimLongMin)
+ return graph->GetIntConstant(kPrimIntMin);
+ return graph->GetIntConstant(static_cast<int32_t>(value));
+ case Primitive::kPrimLong:
+ if (std::isnan(value))
+ return graph->GetLongConstant(0);
+ if (value >= kPrimLongMax)
+ return graph->GetLongConstant(kPrimLongMax);
+ if (value <= kPrimLongMin)
+ return graph->GetLongConstant(kPrimLongMin);
+ return graph->GetLongConstant(static_cast<int64_t>(value));
+ case Primitive::kPrimFloat:
+ return graph->GetFloatConstant(static_cast<float>(value));
+ default:
+ return nullptr;
+ }
+ }
+ return nullptr;
+}
+
HConstant* HUnaryOperation::TryStaticEvaluation() const {
if (GetInput()->IsIntConstant()) {
int32_t value = Evaluate(GetInput()->AsIntConstant()->GetValue());
diff --git a/compiler/optimizing/nodes.h b/compiler/optimizing/nodes.h
index 0089f22..cb2e5cc 100644
--- a/compiler/optimizing/nodes.h
+++ b/compiler/optimizing/nodes.h
@@ -2982,6 +2982,10 @@
bool CanBeMoved() const OVERRIDE { return true; }
bool InstructionDataEquals(HInstruction* other ATTRIBUTE_UNUSED) const OVERRIDE { return true; }
+ // Try to statically evaluate the conversion and return a HConstant
+ // containing the result. If the input cannot be converted, return nullptr.
+ HConstant* TryStaticEvaluation() const;
+
DECLARE_INSTRUCTION(TypeConversion);
private: