Hi all, please review this changes into risc-v floating point copysign and
signum intrinsics.
CopySign - returns first argument with the sign of second. On risc-v we have
`fsgnj.x` instruction, which can implement this intrinsic.
Signum - returns input value if it is +/- 0.0 or NaN, otherwise 1.0 with the
sign of input value returned. On risc-v we can use `fclass.x` to specify type
of input value and return appropriate value.
Tests:
Performance tests on t-head board:
With intrinsics:
Benchmark (seed) Mode Cnt Score Error Units
MathBench.copySignDouble 0 thrpt 8 34156.580 ± 76.272 ops/ms
MathBench.copySignFloat 0 thrpt 8 34181.731 ± 38.182 ops/ms
MathBench.signumDouble 0 thrpt 8 31977.258 ± 1122.327 ops/ms
MathBench.signumFloat 0 thrpt 8 31836.852 ± 56.013 ops/ms
Intrinsics turned off (`-XX:+UnlockDiagnosticVMOptions
-XX:-UseCopySignIntrinsic -XX:-UseSignumIntrinsic`):
Benchmark (seed) Mode Cnt Score Error Units
MathBench.copySignDouble 0 thrpt 8 31000.996 ± 943.094 ops/ms
MathBench.copySignFloat 0 thrpt 8 30678.016 ± 28.087 ops/ms
MathBench.signumDouble 0 thrpt 8 25435.010 ± 2047.085 ops/ms
MathBench.signumFloat 0 thrpt 8 25257.058 ± 79.175 ops/ms
Regression tests: tier1, hotspot:tier2 on risc-v board.
Also, changed name of one micro test: before we had: `sigNumDouble` and
`signumFloat` tests, they does not matches to `signum` or `sigNum`. Now we have
similar part: `signum`.
Performance tests has been changed a bit, to check intrinsics result better,
diff to modify tests:
diff --git a/test/micro/org/openjdk/bench/java/lang/MathBench.java
b/test/micro/org/openjdk/bench/java/lang/MathBench.java
index 6cd1353907e..0bee25366bf 100644
--- a/test/micro/org/openjdk/bench/java/lang/MathBench.java
+++ b/test/micro/org/openjdk/bench/java/lang/MathBench.java
@@ -143,12 +143,12 @@ public double ceilDouble() {
@Benchmark
public double copySignDouble() {
- return Math.copySign(double81, doubleNegative12);
+ return Math.copySign(double81, doubleNegative12) +
Math.copySign(double81, double2) + Math.copySign(double4Dot1, doubleNegative12);
}
@Benchmark
public float copySignFloat() {
- return Math.copySign(floatNegative99, float1);
+ return Math.copySign(floatNegative99, float1) + Math.copySign(eFloat,
float1) + Math.copySign(eFloat, floatNegative99);
}
@Benchmark
@@ -472,12 +472,12 @@ public float scalbFloatInt() {
@Benchmark
public double sigNumDouble() {
- return Math.signum(double4Dot1);
+ return Math.signum(double4Dot1) + Math.signum(doubleNegative12) +
Math.signum(double81);
}
@Benchmark
public double signumFloat() {
- return Math.signum(floatNegative99);
+ return Math.signum(floatNegative99) + Math.signum(float2) +
Math.signum(float7);
}
@Benchmark
-------------
Commit messages:
- Implement copySign and signum intrinsics
Changes: https://git.openjdk.org/jdk/pull/16186/files
Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=16186&range=00
Issue: https://bugs.openjdk.org/browse/JDK-8317971
Stats: 97 lines in 5 files changed: 96 ins; 0 del; 1 mod
Patch: https://git.openjdk.org/jdk/pull/16186.diff
Fetch: git fetch https://git.openjdk.org/jdk.git pull/16186/head:pull/16186
PR: https://git.openjdk.org/jdk/pull/16186
