We can't yet run the behavior tests with stage3, but at least we can run
them with stage2, and we can use the proper test matrix.
This commit also adds use_llvm and ofmt to the zig build system.
These targets now have a similar disagreement with LLVM about the
alignment of 128-bit integers as x86_64:
* riscv64
* powerpc64
* powerpc64le
* mips64
* mips64el
* sparcv9
See #2987
For x86_64, LLVMABIAlignmentOfType(i128) reports 8. However I think 16
is a better number for two reasons:
1. Better machine code when loading into SIMD register.
2. The C ABI wants 16 for extern structs.
Prior to this commit, the logic for ABI size and ABI alignment for
integers was naive and incorrect. This results in wasted hardware as
well as undefined behavior in the LLVM backend when we memset an
incorrect number of bytes to 0xaa due to disagreeing with LLVM about the
ABI size of integers.
This commit introduces a "max int align" value which is different per
Target. This value is used to derive the ABI size and alignment of all
integers.
This commit makes an interesting change from stage1, which treats
128-bit integers as 16-bytes aligned for x86_64-linux. stage1 is
incorrect. The maximum integer alignment on this system is only 8 bytes.
This change breaks the behavior test called "128-bit cmpxchg" because on
that target, 128-bit cmpxchg does require a 16-bytes aligned pointer to
a 128 bit integer. However, this alignment property does not belong on
*all* 128 bit integers - only on the pointer type in the `@cmpxchg`
builtin function prototype. The user can then use an alignment override
annotation on a 128-bit integer variable or struct field to obtain such
a pointer.
Adding `unreachable` prevents the futex code from being inspected during
a single-threaded build. Without futex, first draft BYOS packages don't
need to implement `nanosleep` to get a single-threaded "hello world"
program working.
Use of `assert()` did not achieve the desired effect of avoiding futex
in a single-threaded build.
The previous float-parsing method was lacking in a lot of areas. This
commit introduces a state-of-the art implementation that is both
accurate and fast to std.
Code is derived from working repo https://github.com/tiehuis/zig-parsefloat.
This includes more test-cases and performance numbers that are present
in this commit.
* Accuracy
The primary testing regime has been using test-data found at
https://github.com/tiehuis/parse-number-fxx-test-data. This is a fork of
upstream with support for f128 test-cases added. This data has been
verified against other independent implementations and represents
accurate round-to-even IEEE-754 floating point semantics.
* Performance
Compared to the existing parseFloat implementation there is ~5-10x
performance improvement using the above corpus. (f128 parsing excluded
in below measurements).
** Old
$ time ./test_all_fxx_data
3520298/5296694 succeeded (1776396 fail)
________________________________________________________
Executed in 28.68 secs fish external
usr time 28.48 secs 0.00 micros 28.48 secs
sys time 0.08 secs 694.00 micros 0.08 secs
** This Implementation
$ time ./test_all_fxx_data
5296693/5296694 succeeded (1 fail)
________________________________________________________
Executed in 4.54 secs fish external
usr time 4.37 secs 515.00 micros 4.37 secs
sys time 0.10 secs 171.00 micros 0.10 secs
Further performance numbers can be seen using the
https://github.com/tiehuis/simple_fastfloat_benchmark/ repository, which
compares against some other well-known string-to-float conversion
functions. A breakdown can be found here:
0d9f020f1a/PERFORMANCE.md (commit-b15406a0d2e18b50a4b62fceb5a6a3bb60ca5706)
In summary, we are within 20% of the C++ reference implementation and
have about ~600-700MB/s throughput on a Intel I5-6500 3.5Ghz.
* F128 Support
Finally, f128 is now completely supported with full accuracy. This does
use a slower path which is possible to improve in future.
* Behavioural Changes
There are a few behavioural changes to note.
- `parseHexFloat` is now redundant and these are now supported directly
in `parseFloat`.
- We implement round-to-even in all parsing routines. This is as
specified by IEEE-754. Previous code used different rounding
mechanisms (standard was round-to-zero, hex-parsing looked to use
round-up) so there may be subtle differences.
Closes#2207.
Fixes#11169.
* edwards25519: fix X coordinate of the base point
Reported by @OfekShochat -- Thanks!
* edwards25519: reduce public scalar when the top bit is set, not cleared
This is an optimization for the unexpected case of a scalar
larger than the field size.
Fixes#11563
* edwards25519: add a test implicit reduction of invalid scalars
Instead, just return ChildProcess directly. This structure does not
require a stable address, so we can put it on the stack just fine. If
someone wants it on the heap they should do.
const proc = try allocator.create(ChildProcess);
proc.* = ChildProcess.init(args, allocator);
18d6523888ef08bc66eb808075d13c5e00b8fcf4 regressed compiler-rt tests for
stage1 because it removed a workaround. I updated the comment to better
explain what exactly the workaround is so that it won't happen again.
This reverts commit 75c9936737a6ba991d4ef187ddc9d51bc0ad0998, reversing
changes made to 7f13f5cd5f5a518638b15d7225eae2d88ec1efb5.
I don't think `runZigBuild` belongs in std.testing. We already have
`test/standalone/*` for this.
Additionally test names should explain what they are testing rather than
referencing GitHub issue numbers.
This reverts commit 7f13f5cd5f5a518638b15d7225eae2d88ec1efb5.
I'd like to review this one before it goes in. This is an awfully
specific API that I don't think belongs in std.testing. Also I don't
want any code snippets in doc strings. We have doctests for that.
* remove need for manual string concatenation for building binaries in test blocks
* include small program snippet to show how to get binary path with subslicing
The reason for having `@tan` is that we already have `@sin` and `@cos`
because some targets have machine code instructions for them, but in the
case that the implementation needs to go into compiler-rt, sin, cos, and
tan all share a common dependency which includes a table of data. To
avoid duplicating this table of data, we promote tan to become a builtin
alongside sin and cos.
ZIR: The tag enum is at capacity so this commit moves
`field_call_bind_named` to be `extended`. I measured this as one of
the least used tags in the zig codebase.
Fix libc math suffix for `f32` being wrong in both stage1 and stage2.
stage1: add missing libc prefix for float functions.
* std.math.snan: fix compilation error. Also make it and nan inline.
* LLVM: use a proper enum type for float op instead of enum literal.
Also various cleanups.
* LLVM: use LLVMBuildVectorSplat for vector splat AIR instruction.
- also the bindings had parameter order wrong
* LLVM: additionally handle f16 lowering. For now all targets report OK
but I think we will need to add some exceptions to this list.
* unify the logic for exporting math functions from compiler-rt,
with the appropriate suffixes and prefixes.
- add all missing f128 and f80 exports. Functions with missing
implementations call other functions and have TODO comments.
- also add f16 functions
* move math functions from freestanding libc to compiler-rt (#7265)
* enable all the f128 and f80 code in the stage2 compiler and behavior
tests (#11161).
* update std lib to use builtins rather than `std.math`.
