Before this commit, compiling an empty main with Stage 2 on macOS x86_64 results in
```
../stage2/bin/zig build-exe -ODebug -fLLVM empty_main.zig
error: sub-compilation of compiler_rt failed
[...]/zig/stage2/lib/zig/std/special/compiler_rt/os_version_check.zig:26:10: error: TODO: Sema.zirStructInit for runtime-known struct values
```
By assigning the value to a variable we can sidestep the issue for now.
Instead use the standarized option for communicating the
zig compiler backend at comptime, which is `zig_backend`. This was
introduced in commit 1c24ef0d0b09a12a1fe98056f2fc04de78a82df3.
This allows stage2 to build more of compiler-rt.
I also changed `-%` to `-` for comptime ints in the div and mul
implementations of compiler-rt. This is clearer code and also happens to
work around a bug in stage2.
This improves readability as well as compatibility with stage2. Most of
compiler-rt is now enabled for stage2 with just a few functions disabled
(until stage2 passes more behavior tests).
- neg can only overflow, if a == MIN
- case `-0` is properly handled by hardware, so overflow check by comparing
`a == MIN` is sufficient
- tests: MIN, MIN+1, MIN+4, -42, -7, -1, 0, 1, 7..
See #1290
- abs can only overflow, if a == MIN
- comparing the sign change from wrapping addition is branchless
- tests: MIN, MIN+1,..MIN+4, -42, -7, -1, 0, 1, 7..
See #1290
Before, `std.Progress` was printing unwanted stuff to stderr. Now, the
test runner's logic to detect whether we should print each test as a
separate line to stderr is properly activated.
- adds __cmpsi2, __cmpdi2, __cmpti2
- adds __ucmpsi2, __ucmpdi2, __ucmpti2
- use 2 if statements with 2 temporaries and a constant
- tests: MIN, MIN+1, MIN/2, -1, 0, 1, MAX/2, MAX-1, MAX if applicable
See #1290
- use negXi2.zig to prevent confusion with negXf2.zig
- used for size optimized builds and machines without carry instruction
- tests: special cases 0, -INT_MIN
* use divTrunc range and shift with constant offsets
See #1290
- each byte gets masked, shifted and combined
- use boring masks instead of comptime for readability
- tests: bit patterns with reverse operation, if applicable
See #1290
from zig-specific options to generally recognized zig build options that
any project can take advantage of. See the updated usage text for more
details.
- use Bit Twiddling Hacks: Compute parity in parallel
- test cases derived from popcount.zig
- tests: compare naive approach 10_000 times with random numbers created
from naive seed 42
- compiler_rt.zig: sort by LLVM builtin order and add comments to improve structure
See #1290
- apply simpler approach than LLVM for __popcountdi2
taken from The Art of Computer Programming and generalized
- rename popcountdi2.zig to popcount.zig
- test cases derived from popcountdi2_test.zig
- tests: compare naive approach 10_000 times with
random numbers created from naive seed 42
See #1290
The BPF target does not support mutable global variables. Mark the BPF
target as a target that does not support atomic variables in order to
avoid including the global spinlock table provided in compiler_rt.
LLVM and compiler-rt must agree on how the parameters are passed, it
turns out that in LLVM13 something changed and broke the test case for
AArch64 systems.
It has nothing to do with fma at all.
Closes#9900
After a discussion about language specs, this seems like the best way to
go, because it's simpler to reason about both for humans and compilers.
The `bitcast_result_ptr` ZIR instruction is no longer needed.
This commit also implements writing enums, arrays, and vectors to
virtual memory at compile-time.
This unlocked some more of compiler-rt being able to build, which
in turn unlocks saturating arithmetic behavior tests.
There was also a memory leak in the comptime closure system which is now
fixed.
AIR:
* div is renamed to div_trunc.
* Add div_float, div_floor, div_exact.
- Implemented in Sema and LLVM codegen. C backend has a stub.
Improvements to std.math.big.Int:
* Add `eqZero` function to `Mutable`.
* Fix incorrect results for `divFloor`.
Compiler-rt:
* Add muloti4 to the stage2 section.
* work around a stage1 miscompilation leading to the wrong integer
comparison predicate being emitted.
* fix the bug of not annotating callsites with the calling convention
of the callee, leading to undefined behavior.
* add the `nobuiltin` attribute when building freestanding libc or
compiler_rt libraries to prevent e.g. memcpy from being "optimized"
into a call to itself.
* compiler-rt: change a call to be comptime to make the generated LLVM
IR simpler and easier to study.
I still can't enable the widening tests due to the compiler-rt compare
function being miscompiled in some not-yet-diagnosed way.
libc requires this to use `long double` which is sometimes the same as
f128, sometimes not.
Also for an unknown reason, aarch64 is getting an invalid result for the
`@mulAdd` behavior test for f128. See #9900.
* move fmaq from freestanding libc to compiler_rt, unconditionally
exported weak_odr.
* stage1: add fmaf, fmal, fmaq as symbols that compiler-rt might
generate calls to.
* stage1: lower `@mulAdd` directly to a call to `fmaq` instead of to
the LLVM intrinsic because LLVM will lower it to `fmal` even when the
target's `long double` is not equivalent to `f128`.
This commit is intended to fix the test suite which is failing on the
previous commit.
std: add f128 implementations of fma, frexp, and ilogb. Expose `fmal` in
zig's freestanding libc. This makes `@mulAdd` work correctly for f128.
Fixes a CI regression from yesterday, where I added a usage of f128
`@mulAdd` into the self-hosted compiler.
Before, Sema for comptime `@bitCast` would return the same Value but
change the Type. This gave invalid results because, for example, an
integer Value when the Type is a float would be interpreted numerically,
but `@bitCast` needs it to reinterpret how they would be stored in
memory.
This requires a mechanism to serialize a Value to a byte buffer and
deserialize a Value from a byte buffer.
Not done yet, but needs to happen: comptime dereferencing a pointer
to a Decl needs to perform a comptime bitcast on the loaded value.
Currently the value is silently wrong in the same way that `@bitCast`
was silently wrong before this commit.
The logic in Value for handling readFromMemory for large integers is
only correct for small integers. It needs to be fleshed out for proper
big integers.
As part of this change:
* std.math.big.Int: initial implementations of readTwosComplement and
writeTwosComplement. They only support bit_count <= 128 so far and
panic otherwise.
* compiler-rt: move the compareXf2 exports over to the stage2 section.
Even with the improvements in this commit, I'm still seeing test
failures in the widening behavior tests; more investigation is
needed.
