ARM64: FP16.floor() intrinsic for ARMv8
This CL implements an intrinsic for floor() method with ARMv8.2 FP16
instructions. This intrinsic calls a template GenerateFP16Round function
which will be used to implement other intrinisics such as ceil and
rint.
This intrinsic implementation achieves bit-level compatibility with the
original Java implementation android.util.Half.floor().
The time required in milliseconds to execute the below code on Pixel3:
- Java implementation android.util.Half.floor():
- big cluster only: 18623
- little cluster only: 60424
- arm64 Intrinisic implementation:
- big cluster only: 14213 (~24% faster)
- little cluster only: 54398 (~10% faster)
Analysis of this function with simpleperf showed that approximately only
60-65% of the time is spent in libcore.util.FP16.floor. So the percentage
improvement using intrinsics is likely to be more than the numbers stated
above.
Another reason that the performance improvement with intrinsic is lower
than expected is because the java implementation for values between -1 and
1 (abs < 0x3c00) only requires a few instructions and should almost give
a similar performance to the intrinsic in this case. In the benchmark function
below, 46.8% of the values tested are between -1 and 1.
public static short benchmarkFloor(){
short ret = 0;
long before = 0;
long after = 0;
before = System.currentTimeMillis();
for(int i = 0; i < 50000; i++){
for (short h = Short.MIN_VALUE; h < Short.MAX_VALUE; h++) {
ret += FP16.floor(h);
}
}
after = System.currentTimeMillis();
System.out.println("Time of FP16.floor (ms): " + (after - before));
System.out.println(ret);
return ret;
}
Test: 580-fp16
Test: art/test/testrunner/run_build_test_target.py -j80 art-test-javac
Change-Id: Iad1dd032d456af54932f13c5cf27228f8652a0b5
diff --git a/compiler/optimizing/intrinsics_arm64.cc b/compiler/optimizing/intrinsics_arm64.cc
index c48aaf5..228255a 100644
--- a/compiler/optimizing/intrinsics_arm64.cc
+++ b/compiler/optimizing/intrinsics_arm64.cc
@@ -3240,6 +3240,38 @@
__ Sxth(out, out); // sign extend due to returning a short type.
}
+template<typename OP>
+void GenerateFP16Round(HInvoke* invoke,
+ CodeGeneratorARM64* const codegen_,
+ MacroAssembler* masm,
+ const OP roundOp) {
+ DCHECK(codegen_->GetInstructionSetFeatures().HasFP16());
+ LocationSummary* locations = invoke->GetLocations();
+ UseScratchRegisterScope scratch_scope(masm);
+ Register out = WRegisterFrom(locations->Out());
+ VRegister half = scratch_scope.AcquireH();
+ __ Fmov(half, WRegisterFrom(locations->InAt(0)));
+ roundOp(half, half);
+ __ Fmov(out, half);
+ __ Sxth(out, out);
+}
+
+void IntrinsicLocationsBuilderARM64::VisitFP16Floor(HInvoke* invoke) {
+ if (!codegen_->GetInstructionSetFeatures().HasFP16()) {
+ return;
+ }
+
+ CreateIntToIntLocations(allocator_, invoke);
+}
+
+void IntrinsicCodeGeneratorARM64::VisitFP16Floor(HInvoke* invoke) {
+ MacroAssembler* masm = GetVIXLAssembler();
+ auto roundOp = [masm](const VRegister& out, const VRegister& in) {
+ __ Frintm(out, in); // Round towards Minus infinity
+ };
+ GenerateFP16Round(invoke, codegen_, masm, roundOp);
+}
+
UNIMPLEMENTED_INTRINSIC(ARM64, ReferenceGetReferent)
UNIMPLEMENTED_INTRINSIC(ARM64, StringStringIndexOf);
diff --git a/compiler/optimizing/intrinsics_arm_vixl.cc b/compiler/optimizing/intrinsics_arm_vixl.cc
index 74e861f..8217980 100644
--- a/compiler/optimizing/intrinsics_arm_vixl.cc
+++ b/compiler/optimizing/intrinsics_arm_vixl.cc
@@ -3072,6 +3072,7 @@
UNIMPLEMENTED_INTRINSIC(ARMVIXL, CRC32UpdateByteBuffer)
UNIMPLEMENTED_INTRINSIC(ARMVIXL, FP16ToFloat)
UNIMPLEMENTED_INTRINSIC(ARMVIXL, FP16ToHalf)
+UNIMPLEMENTED_INTRINSIC(ARMVIXL, FP16Floor)
UNIMPLEMENTED_INTRINSIC(ARMVIXL, StringStringIndexOf);
UNIMPLEMENTED_INTRINSIC(ARMVIXL, StringStringIndexOfAfter);
diff --git a/compiler/optimizing/intrinsics_mips.cc b/compiler/optimizing/intrinsics_mips.cc
index b18bbdd..0bab2a0 100644
--- a/compiler/optimizing/intrinsics_mips.cc
+++ b/compiler/optimizing/intrinsics_mips.cc
@@ -2709,6 +2709,7 @@
UNIMPLEMENTED_INTRINSIC(MIPS, CRC32UpdateByteBuffer)
UNIMPLEMENTED_INTRINSIC(MIPS, FP16ToFloat)
UNIMPLEMENTED_INTRINSIC(MIPS, FP16ToHalf)
+UNIMPLEMENTED_INTRINSIC(MIPS, FP16Floor)
UNIMPLEMENTED_INTRINSIC(MIPS, StringStringIndexOf);
UNIMPLEMENTED_INTRINSIC(MIPS, StringStringIndexOfAfter);
diff --git a/compiler/optimizing/intrinsics_mips64.cc b/compiler/optimizing/intrinsics_mips64.cc
index e4627db..6ed1133 100644
--- a/compiler/optimizing/intrinsics_mips64.cc
+++ b/compiler/optimizing/intrinsics_mips64.cc
@@ -2359,6 +2359,7 @@
UNIMPLEMENTED_INTRINSIC(MIPS64, CRC32UpdateByteBuffer)
UNIMPLEMENTED_INTRINSIC(MIPS64, FP16ToFloat)
UNIMPLEMENTED_INTRINSIC(MIPS64, FP16ToHalf)
+UNIMPLEMENTED_INTRINSIC(MIPS64, FP16Floor)
UNIMPLEMENTED_INTRINSIC(MIPS64, StringStringIndexOf);
UNIMPLEMENTED_INTRINSIC(MIPS64, StringStringIndexOfAfter);
diff --git a/compiler/optimizing/intrinsics_x86.cc b/compiler/optimizing/intrinsics_x86.cc
index 95aa4c0..7bc9b63 100644
--- a/compiler/optimizing/intrinsics_x86.cc
+++ b/compiler/optimizing/intrinsics_x86.cc
@@ -3083,6 +3083,7 @@
UNIMPLEMENTED_INTRINSIC(X86, CRC32UpdateByteBuffer)
UNIMPLEMENTED_INTRINSIC(X86, FP16ToFloat)
UNIMPLEMENTED_INTRINSIC(X86, FP16ToHalf)
+UNIMPLEMENTED_INTRINSIC(X86, FP16Floor)
UNIMPLEMENTED_INTRINSIC(X86, StringStringIndexOf);
UNIMPLEMENTED_INTRINSIC(X86, StringStringIndexOfAfter);
diff --git a/compiler/optimizing/intrinsics_x86_64.cc b/compiler/optimizing/intrinsics_x86_64.cc
index 8dbc0d3..e11208c 100644
--- a/compiler/optimizing/intrinsics_x86_64.cc
+++ b/compiler/optimizing/intrinsics_x86_64.cc
@@ -2750,6 +2750,7 @@
UNIMPLEMENTED_INTRINSIC(X86_64, CRC32UpdateByteBuffer)
UNIMPLEMENTED_INTRINSIC(X86_64, FP16ToFloat)
UNIMPLEMENTED_INTRINSIC(X86_64, FP16ToHalf)
+UNIMPLEMENTED_INTRINSIC(X86_64, FP16Floor)
UNIMPLEMENTED_INTRINSIC(X86_64, StringStringIndexOf);
UNIMPLEMENTED_INTRINSIC(X86_64, StringStringIndexOfAfter);
diff --git a/runtime/hidden_api.h b/runtime/hidden_api.h
index 2ef3522..ec24c42 100644
--- a/runtime/hidden_api.h
+++ b/runtime/hidden_api.h
@@ -357,6 +357,7 @@
case Intrinsics::kVarHandleWeakCompareAndSetRelease:
return 0u;
case Intrinsics::kUnsafeGetLong:
+ case Intrinsics::kFP16Floor:
case Intrinsics::kFP16ToFloat:
case Intrinsics::kFP16ToHalf:
return kAccCorePlatformApi;
diff --git a/runtime/image.cc b/runtime/image.cc
index 06ba946..2b4099f 100644
--- a/runtime/image.cc
+++ b/runtime/image.cc
@@ -29,7 +29,7 @@
namespace art {
const uint8_t ImageHeader::kImageMagic[] = { 'a', 'r', 't', '\n' };
-const uint8_t ImageHeader::kImageVersion[] = { '0', '8', '0', '\0' }; // Chained checksums.
+const uint8_t ImageHeader::kImageVersion[] = { '0', '8', '1', '\0' }; // FP16Floor intrinsic
ImageHeader::ImageHeader(uint32_t image_reservation_size,
uint32_t component_count,
diff --git a/runtime/interpreter/interpreter_intrinsics.cc b/runtime/interpreter/interpreter_intrinsics.cc
index 3759225..4ddf9bb 100644
--- a/runtime/interpreter/interpreter_intrinsics.cc
+++ b/runtime/interpreter/interpreter_intrinsics.cc
@@ -575,6 +575,7 @@
UNIMPLEMENTED_CASE(CRC32UpdateByteBuffer /* (IJII)I */)
UNIMPLEMENTED_CASE(FP16ToFloat /* (S)F */)
UNIMPLEMENTED_CASE(FP16ToHalf /* (F)S */)
+ UNIMPLEMENTED_CASE(FP16Floor /* (S)S */)
INTRINSIC_CASE(VarHandleFullFence)
INTRINSIC_CASE(VarHandleAcquireFence)
INTRINSIC_CASE(VarHandleReleaseFence)
diff --git a/runtime/intrinsics_list.h b/runtime/intrinsics_list.h
index bb41ca7..045c808 100644
--- a/runtime/intrinsics_list.h
+++ b/runtime/intrinsics_list.h
@@ -165,6 +165,7 @@
V(MemoryPokeIntNative, kStatic, kNeedsEnvironmentOrCache, kWriteSideEffects, kCanThrow, "Llibcore/io/Memory;", "pokeIntNative", "(JI)V") \
V(MemoryPokeLongNative, kStatic, kNeedsEnvironmentOrCache, kWriteSideEffects, kCanThrow, "Llibcore/io/Memory;", "pokeLongNative", "(JJ)V") \
V(MemoryPokeShortNative, kStatic, kNeedsEnvironmentOrCache, kWriteSideEffects, kCanThrow, "Llibcore/io/Memory;", "pokeShortNative", "(JS)V") \
+ V(FP16Floor, kStatic, kNeedsEnvironmentOrCache, kNoSideEffects, kNoThrow, "Llibcore/util/FP16;", "floor", "(S)S") \
V(FP16ToFloat, kStatic, kNeedsEnvironmentOrCache, kNoSideEffects, kNoThrow, "Llibcore/util/FP16;", "toFloat", "(S)F") \
V(FP16ToHalf, kStatic, kNeedsEnvironmentOrCache, kNoSideEffects, kNoThrow, "Llibcore/util/FP16;", "toHalf", "(F)S") \
V(StringCharAt, kVirtual, kNeedsEnvironmentOrCache, kReadSideEffects, kCanThrow, "Ljava/lang/String;", "charAt", "(I)C") \
diff --git a/test/580-fp16/src-art/Main.java b/test/580-fp16/src-art/Main.java
index 4aa8d55..815c9f5 100644
--- a/test/580-fp16/src-art/Main.java
+++ b/test/580-fp16/src-art/Main.java
@@ -112,9 +112,35 @@
assertEquals(0xffffe000, TestFP16ToFloatRawIntBits((short)(0xffff))); // QNaN->QNaN
}
+ public static void testFloor() {
+ // These tests have been taken from the cts HalfTest
+ assertEquals(FP16.POSITIVE_INFINITY, FP16.floor(FP16.POSITIVE_INFINITY));
+ assertEquals(FP16.NEGATIVE_INFINITY, FP16.floor(FP16.NEGATIVE_INFINITY));
+ assertEquals(FP16.POSITIVE_ZERO, FP16.floor(FP16.POSITIVE_ZERO));
+ assertEquals(FP16.NEGATIVE_ZERO, FP16.floor(FP16.NEGATIVE_ZERO));
+ assertEquals(FP16.NaN, FP16.floor(FP16.NaN));
+ assertEquals(FP16.LOWEST_VALUE, FP16.floor(FP16.LOWEST_VALUE));
+ assertEquals(FP16.POSITIVE_ZERO, FP16.floor(FP16.MIN_NORMAL));
+ assertEquals(FP16.POSITIVE_ZERO, FP16.floor((short) 0x3ff));
+ assertEquals(FP16.POSITIVE_ZERO, FP16.floor(FP16.toHalf(0.2f)));
+ assertEquals(-1.0f, FP16.toFloat(FP16.floor(FP16.toHalf(-0.2f))));
+ assertEquals(-1.0f, FP16.toFloat(FP16.floor(FP16.toHalf(-0.7f))));
+ assertEquals(FP16.POSITIVE_ZERO, FP16.floor(FP16.toHalf(0.7f)));
+ assertEquals(124.0f, FP16.toFloat(FP16.floor(FP16.toHalf(124.7f))));
+ assertEquals(-125.0f, FP16.toFloat(FP16.floor(FP16.toHalf(-124.7f))));
+ assertEquals(124.0f, FP16.toFloat(FP16.floor(FP16.toHalf(124.2f))));
+ assertEquals(-125.0f, FP16.toFloat(FP16.floor(FP16.toHalf(-124.2f))));
+ // floor for NaN values
+ assertEquals((short) 0x7e01, FP16.floor((short) 0x7c01));
+ assertEquals((short) 0x7f00, FP16.floor((short) 0x7d00));
+ assertEquals((short) 0xfe01, FP16.floor((short) 0xfc01));
+ assertEquals((short) 0xff00, FP16.floor((short) 0xfd00));
+ }
+
public static void main(String args[]) {
testHalfToFloatToHalfConversions();
testToHalf();
testToFloat();
+ testFloor();
}
}