Add support for long-to-float in the optimizing compiler.
- Add support for the long-to-float Dex instruction in the
optimizing compiler.
- Have art::x86_64::X86_64Assembler::cvtsi2ss work with
64-bit operands.
- Generate x86, x86-64 and ARM (but not ARM64) code for
long to float HTypeConversion nodes.
- Add related tests to test/422-type-conversion.
Change-Id: Ic983cbeb1ae2051add40bc519a8f00a6196166c9
diff --git a/compiler/optimizing/code_generator_x86.cc b/compiler/optimizing/code_generator_x86.cc
index 705065d..b21abad 100644
--- a/compiler/optimizing/code_generator_x86.cc
+++ b/compiler/optimizing/code_generator_x86.cc
@@ -1435,6 +1435,13 @@
break;
case Primitive::kPrimLong:
+ // Processing a Dex `long-to-float' instruction.
+ locations->SetInAt(0, Location::RequiresRegister());
+ locations->SetOut(Location::RequiresFpuRegister());
+ locations->AddTemp(Location::RequiresFpuRegister());
+ locations->AddTemp(Location::RequiresFpuRegister());
+ break;
+
case Primitive::kPrimDouble:
LOG(FATAL) << "Type conversion from " << input_type
<< " to " << result_type << " not yet implemented";
@@ -1614,15 +1621,48 @@
case Primitive::kPrimFloat:
switch (input_type) {
- // Processing a Dex `int-to-float' instruction.
case Primitive::kPrimByte:
case Primitive::kPrimShort:
case Primitive::kPrimInt:
case Primitive::kPrimChar:
+ // Processing a Dex `int-to-float' instruction.
__ cvtsi2ss(out.AsFpuRegister<XmmRegister>(), in.AsRegister<Register>());
break;
- case Primitive::kPrimLong:
+ case Primitive::kPrimLong: {
+ // Processing a Dex `long-to-float' instruction.
+ Register low = in.AsRegisterPairLow<Register>();
+ Register high = in.AsRegisterPairHigh<Register>();
+ XmmRegister result = out.AsFpuRegister<XmmRegister>();
+ XmmRegister temp = locations->GetTemp(0).AsFpuRegister<XmmRegister>();
+ XmmRegister constant = locations->GetTemp(1).AsFpuRegister<XmmRegister>();
+
+ // Operations use doubles for precision reasons (each 32-bit
+ // half of a long fits in the 53-bit mantissa of a double,
+ // but not in the 24-bit mantissa of a float). This is
+ // especially important for the low bits. The result is
+ // eventually converted to float.
+
+ // low = low - 2^31 (to prevent bit 31 of `low` to be
+ // interpreted as a sign bit)
+ __ subl(low, Immediate(0x80000000));
+ // temp = int-to-double(high)
+ __ cvtsi2sd(temp, high);
+ // temp = temp * 2^32
+ __ LoadLongConstant(constant, k2Pow32EncodingForDouble);
+ __ mulsd(temp, constant);
+ // result = int-to-double(low)
+ __ cvtsi2sd(result, low);
+ // result = result + 2^31 (restore the original value of `low`)
+ __ LoadLongConstant(constant, k2Pow31EncodingForDouble);
+ __ addsd(result, constant);
+ // result = result + temp
+ __ addsd(result, temp);
+ // result = double-to-float(result)
+ __ cvtsd2ss(result, result);
+ break;
+ }
+
case Primitive::kPrimDouble:
LOG(FATAL) << "Type conversion from " << input_type
<< " to " << result_type << " not yet implemented";
@@ -1636,11 +1676,11 @@
case Primitive::kPrimDouble:
switch (input_type) {
- // Processing a Dex `int-to-double' instruction.
case Primitive::kPrimByte:
case Primitive::kPrimShort:
case Primitive::kPrimInt:
case Primitive::kPrimChar:
+ // Processing a Dex `int-to-double' instruction.
__ cvtsi2sd(out.AsFpuRegister<XmmRegister>(), in.AsRegister<Register>());
break;
@@ -1652,23 +1692,18 @@
XmmRegister temp = locations->GetTemp(0).AsFpuRegister<XmmRegister>();
XmmRegister constant = locations->GetTemp(1).AsFpuRegister<XmmRegister>();
- // Binary encoding of 2^32 for type double.
- const int64_t c1 = INT64_C(0x41F0000000000000);
- // Binary encoding of 2^31 for type double.
- const int64_t c2 = INT64_C(0x41E0000000000000);
-
// low = low - 2^31 (to prevent bit 31 of `low` to be
// interpreted as a sign bit)
__ subl(low, Immediate(0x80000000));
// temp = int-to-double(high)
__ cvtsi2sd(temp, high);
// temp = temp * 2^32
- __ LoadLongConstant(constant, c1);
+ __ LoadLongConstant(constant, k2Pow32EncodingForDouble);
__ mulsd(temp, constant);
// result = int-to-double(low)
__ cvtsi2sd(result, low);
// result = result + 2^31 (restore the original value of `low`)
- __ LoadLongConstant(constant, c2);
+ __ LoadLongConstant(constant, k2Pow31EncodingForDouble);
__ addsd(result, constant);
// result = result + temp
__ addsd(result, temp);