This reverts commit 0c99ba1eab63865592bb084feb271cd4e4b0357e, reversing
changes made to 5f92b070bf284f1493b1b5d433dd3adde2f46727.
This caused a CI failure when it landed in master branch due to a
128-bit `@byteSwap` in std.mem.
`nextAfter()` returns the next representable value after `x` in the direction of `y` and is a standard math library function ([C++](https://en.cppreference.com/w/cpp/numeric/math/nextafter), [Java](https://docs.oracle.com/javase/8/docs/api/java/lang/Math.html#nextAfter-double-double-)). It is primarily useful for bitwise incrementing/decrementing floats.
This implementation supports runtime integers, runtime floats and `comptime_int`. `comptime_float` is not supported because NaNs/infinities are intentionally difficult to obtain and because I'm not sure if the fact that it's backed by `f128` is supposed to be an implementation detail. Either way, the user could just call the function with the floating-point type whose behavior they want at comptime and then cast the result to `comptime_float`.
The float implementation was ported from mingw-w64 with some slight changes made possible because the Zig standard library doesn't care about raising FP exceptions.
The number of test cases may seem excessive but they should cover every normal and edge case for every float type and are especially important for verifying that `f80` works.
* Generalise NaN handling and make std.math.nan() give quiet NaNs
* Address uses of std.math.qnan_* and std.math.nan_* consts
* Comment out failing test due to issues with signalling NaN
* Fix issue in c_builtins.zig where we need qnan_u32
Most of this migration was performed automatically with `zig fmt`. There
were a few exceptions which I had to manually fix:
* `@alignCast` and `@addrSpaceCast` cannot be automatically rewritten
* `@truncate`'s fixup is incorrect for vectors
* Test cases are not formatted, and their error locations change
The assert is changed from `int != 0` to `int > 0` because negative
integers always return `false`.
Python's `math.log2` does the same and errors for 0 or negative integers.
* docs(std.math): elaborate on difference between absCast and absInt
* docs(std.rand.Random.weightedIndex): elaborate on likelihood
I think this makes it easier to understand.
* langref: add small reminder
* docs(std.fs.path.extension): brevity
* docs(std.bit_set.StaticBitSet): mention the specific types
* std.debug.TTY: explain what purpose this struct serves
This should also make it clearer that this struct is not supposed to provide unrelated terminal manipulation functionality such as setting the cursor position or something because terminals are complicated and we should keep this struct simple and focused on debugging.
* langref(package listing): brevity
* langref: explain what exactly `threadlocal` causes to happen
* std.array_list: link between swapRemove and orderedRemove
Maybe this can serve as a TLDR and make it easier to decide.
* PrefetchOptions.locality: clarify docs that this is a range
This confused me previously and I thought I can only use either 0 or 3.
* fix typos and more
* std.builtin.CallingConvention: document some CCs
* langref: explain possibly cryptic names
I think it helps knowing what exactly these acronyms (@clz and @ctz) and
abbreviations (@popCount) mean.
* variadic function error: add missing preposition
* std.fmt.format docs: nicely hyphenate
* help menu: say what to optimize for
I think this is slightly more specific than just calling it
"optimizations". These are speed optimizations. I used the word
"performance" here.
This reverts commit 3370d58956ecc744a004dff47b0437473f0ef7da.
This commit was done with an LLVM build that did not have assertions
enabled. There are LLVM assertions being triggered due to this commit.
Reopens#10627Reopens#12013Reopens#12027
* Improve and remove duplicate doNotOptimizeAway() implementations
We currently have two doNotOptimizeAway() implementations, one in
std.math and the other one in std.mem.
Maybe we should deprecate one. In the meantime, the std.math one
now just calls the std.mem one.
In a comptime environment, just ignore the value. Previously,
std.mem.doNotOptimizeAway() did not work at comptime.
If the value fits in a CPU register, just tell the compiler we
need that value to be computed, without clobbering anything else.
Only clobber all possibly escaped memory on pointers or large arrays.
Add tests by the way since we didn't had any (we had, but only
indirect ones).
There are still a few occurrences of "stage1" in the standard library
and self-hosted compiler source, however, these instances need a bit
more careful inspection to ensure no breakage.
This allows converting a comptime_int to an optional integer type, which
either behaves the same as an implicit cast or produces null if the
argument is outside the range of the destination type.
