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src/__support/math folder. (#143790)
This is a step in preparation for:
https://discourse.llvm.org/t/rfc-make-clang-builtin-math-functions-constexpr-with-llvm-libc-to-support-c-23-constexpr-math-functions/86450
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LIBC_MATH_SKIP_ACCURATE_PASS is set. (#130811)
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This is a part of #97655.
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declaration" (#98593)
Reverts llvm/llvm-project#98075
bots are broken
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This is a part of #97655.
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The semantics for casting can range from "bitcast" (same representation)
to "different representation", to "type promotion". Here we remove the
cast operator and force usage of `get_val` as the only function to get
the floating point value, making the intent clearer and more consistent.
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- reland #79113
- Fix aarch64 RISC-V build
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Reverts llvm/llvm-project#79113
It broke aarch64 build bot machines.
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This patch reduces the surface of `FPBits`.
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Another patch is needed to cover `DyadicFloat` and `NormalFloat`
constructors.
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According to [wikipedia](https://en.wikipedia.org/wiki/Exponent_bias)
the "biased exponent" is the encoded form that is always positive
whereas the unbiased form is the actual "real" exponent that can be
positive or negative.
`FPBits` seems to be using `unbiased_exponent` to describe the encoded
form (unsigned). This patch simply use `biased` instead of `unbiased`.
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This is step 4 of
https://discourse.llvm.org/t/rfc-customizable-namespace-to-allow-testing-the-libc-when-the-system-libc-is-also-llvms-libc/73079
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Many math functions need to check for floating point rounding modes to
return correct values. Currently most of them use the internal implementation
of `fegetround`, which is platform-dependent and blocking math functions to be
enabled on platforms with unimplemented `fegetround`. In this change, we add
platform independent rounding mode checks and switching math functions to use
them instead. https://github.com/llvm/llvm-project/issues/63016
Reviewed By: sivachandra
Differential Revision: https://reviews.llvm.org/D152280
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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
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Use nearest_integer instructions to improve expf performance.
Performance tests with CORE-MATH's perf tool:
Before the patch:
```
$ ./perf.sh expf
LIBC-location: /home/lnt/experiment/llvm-project/build/projects/libc/lib/libllvmlibc.a
GNU libc version: 2.31
GNU libc release: stable
CORE-MATH reciprocal throughput : 9.860
System LIBC reciprocal throughput : 7.728
LIBC reciprocal throughput : 12.363
$ ./perf.sh expf --latency
LIBC-location: /home/lnt/experiment/llvm-project/build/projects/libc/lib/libllvmlibc.a
GNU libc version: 2.31
GNU libc release: stable
CORE-MATH latency : 42.802
System LIBC latency : 35.941
LIBC latency : 49.808
```
After the patch:
```
$ ./perf.sh expf
LIBC-location: /home/lnt/experiment/llvm/llvm-project/build/projects/libc/lib/libllvmlibc.a
GNU libc version: 2.31
GNU libc release: stable
CORE-MATH reciprocal throughput : 9.441
System LIBC reciprocal throughput : 7.382
LIBC reciprocal throughput : 8.843
$ ./perf.sh expf --latency
LIBC-location: /home/lnt/experiment/llvm/llvm-project/build/projects/libc/lib/libllvmlibc.a
GNU libc version: 2.31
GNU libc release: stable
CORE-MATH latency : 44.192
System LIBC latency : 37.693
LIBC latency : 44.145
```
Reviewed By: zimmermann6
Differential Revision: https://reviews.llvm.org/D130498
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Detect if the architecture supports FMA instructions and if
the targets depend on fma.
Reviewed By: gchatelet
Differential Revision: https://reviews.llvm.org/D123615
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Reduce the polynomial's degree from 7 down to 4.
Currently we use a degree-7 minimax polynomial on an interval of length 2^-7
around 0 to compute `expf`. Based on the suggestion of @santoshn and the RLIBM
project (https://github.com/rutgers-apl/rlibm-all/blob/main/source/float/exp.c)
and the improvement we made with `exp2f` in https://reviews.llvm.org/D122346,
it is possible to have a good polynomial of degree-4 on a subinterval of length
2^(-7) to approximate e^x.
We did try to either reduce the degree of the polynomial down to 3 or increase
the interval size to 2^(-6), but in both cases the number of exceptional values
exploded. So we settle with using a degree-4 polynomial of the interval of
size 2^(-7) around 0.
Reviewed By: sivachandra, zimmermann6, santoshn
Differential Revision: https://reviews.llvm.org/D122418
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modes.
Implement expm1f function that is correctly rounded for all rounding modes. This is based on expf implementation.
From exhaustive testings, using expf implementation, and subtract 1.0 before rounding the final result to single precision
gives correctly rounded results for all |x| > 2^-4 with 1 exception. When |x| < 2^-25, we use x + x^2 (implemented with a
single fma). And for 2^-25 <= |x| <= 2^-4, we use a single degree-8 minimax polynomial generated by Sollya.
Reviewed By: sivachandra, zimmermann6
Differential Revision: https://reviews.llvm.org/D121574
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Implement expf function that is correctly rounded for all rounding modes.
Reviewed By: sivachandra, zimmermann6
Differential Revision: https://reviews.llvm.org/D121440
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This expands the pattern suggest in https://reviews.llvm.org/D95850 to all
math functions.
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