Alex Brachet
7d11a592c5
[libc] Fix some math conversion warnings
...
Differential Revision: https://reviews.llvm.org/D146738
2023-03-23 17:07:19 +00:00
Tue Ly
0aa9593c2f
[libc][math] Set floating point exceptions for exp*f, sinhf, and coshf.
...
Set FE_OVERFLOW and FE_UNDERFLOW for expf, exp2f, exp10f, expm1f, sinhf
and coshf.
Reviewed By: sivachandra, renyichen
Differential Revision: https://reviews.llvm.org/D144340
2023-02-24 12:56:39 -05:00
Guillaume Chatelet
737e1cd161
[libc] Move likely/unlikely to the optimization header
2023-02-10 15:31:28 +00:00
Guillaume Chatelet
29f8e076bd
[libc][NFC] Move attributes from common to macros folder
2023-02-07 13:16:53 +00:00
Tue Ly
1c89ae71ea
[libc][math] Improve sinhf and coshf performance.
...
Optimize `sinhf` and `coshf` by computing exp(x) and exp(-x) simultaneously.
Currently `sinhf` and `coshf` are implemented using the following formulas:
```
sinh(x) = 0.5 *(exp(x) - 1) - 0.5*(exp(-x) - 1)
cosh(x) = 0.5*exp(x) + 0.5*exp(-x)
```
where `exp(x)` and `exp(-x)` are calculated separately using the formula:
```
exp(x) ~ 2^hi * 2^mid * exp(dx)
~ 2^hi * 2^mid * P(dx)
```
By expanding the polynomial `P(dx)` into even and odd parts
```
P(dx) = P_even(dx) + dx * P_odd(dx)
```
we can see that the computations of `exp(x)` and `exp(-x)` have many things in common,
namely:
```
exp(x) ~ 2^(hi + mid) * (P_even(dx) + dx * P_odd(dx))
exp(-x) ~ 2^(-(hi + mid)) * (P_even(dx) - dx * P_odd(dx))
```
Expanding `sinh(x)` and `cosh(x)` with respect to the above formulas, we can compute
these two functions as follow in order to maximize the sharing parts:
```
sinh(x) = (e^x - e^(-x)) / 2
~ 0.5 * (P_even * (2^(hi + mid) - 2^(-(hi + mid))) +
dx * P_odd * (2^(hi + mid) + 2^(-(hi + mid))))
cosh(x) = (e^x + e^(-x)) / 2
~ 0.5 * (P_even * (2^(hi + mid) + 2^(-(hi + mid))) +
dx * P_odd * (2^(hi + mid) - 2^(-(hi + mid))))
```
So in this patch, we perform the following optimizations for `sinhf` and `coshf`:
# Use the above formulas to maximize sharing intermediate results,
# Apply similar optimizations from https://reviews.llvm.org/D133870
Performance benchmark using `perf` tool from the CORE-MATH project on Ryzen 1700:
For `sinhf`:
```
$ CORE_MATH_PERF_MODE="rdtsc" ./perf.sh sinhf
GNU libc version: 2.35
GNU libc release: stable
CORE-MATH reciprocal throughput : 16.718
System LIBC reciprocal throughput : 63.151
BEFORE:
LIBC reciprocal throughput : 90.116
LIBC reciprocal throughput : 28.554 (with `-msse4.2` flag)
LIBC reciprocal throughput : 22.577 (with `-mfma` flag)
AFTER:
LIBC reciprocal throughput : 36.482
LIBC reciprocal throughput : 16.955 (with `-msse4.2` flag)
LIBC reciprocal throughput : 13.943 (with `-mfma` flag)
$ CORE_MATH_PERF_MODE="rdtsc" ./perf.sh sinhf --latency
GNU libc version: 2.35
GNU libc release: stable
CORE-MATH latency : 48.821
System LIBC latency : 137.019
BEFORE
LIBC latency : 97.122
LIBC latency : 84.214 (with `-msse4.2` flag)
LIBC latency : 71.611 (with `-mfma` flag)
AFTER
LIBC latency : 54.555
LIBC latency : 50.865 (with `-msse4.2` flag)
LIBC latency : 48.700 (with `-mfma` flag)
```
For `coshf`:
```
$ CORE_MATH_PERF_MODE="rdtsc" ./perf.sh coshf
GNU libc version: 2.35
GNU libc release: stable
CORE-MATH reciprocal throughput : 16.939
System LIBC reciprocal throughput : 19.695
BEFORE:
LIBC reciprocal throughput : 52.845
LIBC reciprocal throughput : 29.174 (with `-msse4.2` flag)
LIBC reciprocal throughput : 22.553 (with `-mfma` flag)
AFTER:
LIBC reciprocal throughput : 37.169
LIBC reciprocal throughput : 17.805 (with `-msse4.2` flag)
LIBC reciprocal throughput : 14.691 (with `-mfma` flag)
$ CORE_MATH_PERF_MODE="rdtsc" ./perf.sh coshf --latency
GNU libc version: 2.35
GNU libc release: stable
CORE-MATH latency : 48.478
System LIBC latency : 48.044
BEFORE
LIBC latency : 99.123
LIBC latency : 85.595 (with `-msse4.2` flag)
LIBC latency : 72.776 (with `-mfma` flag)
AFTER
LIBC latency : 57.760
LIBC latency : 53.967 (with `-msse4.2` flag)
LIBC latency : 50.987 (with `-mfma` flag)
```
Reviewed By: orex, zimmermann6
Differential Revision: https://reviews.llvm.org/D133913
2022-09-15 09:20:39 -04:00
Kirill Okhotnikov
89ed5b7c50
[libc][math] Added auxiliary function log2_eval for asinhf/acoshf/atanhf.
...
1) `double log2_eval(double)` function added with better than float precision is added.
2) Some refactoring done to put all auxiliary functions and corresponding data
to one place to reuse the code.
3) Added tests for new functions.
4) Performance and precision tests of the function shows, that it more precise than exiting log2,
(no exceptional cases), but timing is ~5% higer that on current one.
Differential Revision: https://reviews.llvm.org/D132809
2022-08-30 22:39:54 +02:00
Kirill Okhotnikov
fcb9d7e2cf
[libc][math] Added coshf function.
...
Differential Revision: https://reviews.llvm.org/D129275
2022-07-29 16:57:28 +02:00
