ziglang/zig

Fork 772

Code Issues 708 Pull requests 293 Activity Actions 30

WIP: libzigc: fmaf #31105

Closed

usebeforefree wants to merge 1 commit from usebeforefree/zig:libzigc-fmaf into master

pull from: usebeforefree/zig:libzigc-fmaf

merge into: ziglang:master

ziglang:master

ziglang:elfv2

ziglang:spork8

ziglang:restricted

ziglang:0.16.x

ziglang:panic-rewrite

ziglang:parking-futex-lockfree

ziglang:windows-Io-cleanup

ziglang:Io-watch

ziglang:ParseCommandLineOptions

ziglang:windows-async-files

ziglang:poll-ring

ziglang:debug-file-leaks-differently

ziglang:debug-file-leaks

ziglang:ProcessPrng

ziglang:elfv2-dyn

ziglang:jobserver

ziglang:threadtheft

ziglang:io-threaded-no-queue

ziglang:0.15.x

ziglang:Io.net

ziglang:comptime-allocator

ziglang:restricted-function-pointers

ziglang:cli

ziglang:wasm-linker-writer

ziglang:wrangle-writer-buffering

ziglang:sha1-stream

ziglang:async-await-demo

ziglang:fixes

ziglang:0.14.x

ziglang:ast-node-methods

ziglang:macos-debug-info

ziglang:make-vs-configure

ziglang:fuzz-macos

ziglang:sans-aro

ziglang:ArrayList-reserve

ziglang:incr-bug

ziglang:llvm-ir-nosanitize-metadata

ziglang:ci-tarballs

ziglang:ci-scripts

ziglang:threadpool

ziglang:0.12.x

ziglang:new-pkg-hash

ziglang:json-diagnostics

ziglang:more-doctests

ziglang:rework-comptime-mutation

ziglang:0.11.x

ziglang:ci-perf-comment

ziglang:stage2-async

ziglang:0.10.x

ziglang:autofix

ziglang:0.9.x

ziglang:aro

ziglang:hcs

ziglang:0.8.x

ziglang:0.7.x

Conversation 2 Commits 1 Files changed 13 +1 -231

usebeforefree commented

2026年02月03日 18:42:58 +01:00

First-time contributor

Copy link

Child of #30978

The fmaf function is implemented in compiler_rt.

Remove fmaf.c.

There is a TODO inside of the method, though for some reason the tests pass either way. I implemented it, though I want to see if the tests pass here as well.

Child of https://codeberg.org/ziglang/zig/issues/30978 The `fmaf` function is implemented in `compiler_rt`. Remove `fmaf.c`. There is a TODO inside of the method, though for some reason the tests pass either way. I implemented it, though I want to see if the tests pass here as well.

usebeforefree added 1 commit

2026年02月03日 18:42:59 +01:00

remove fmaf.c, use compiler_rt implementation

All checks were successful

ci / aarch64-macos-release (pull_request) Successful in 28m40s

Details

ci / x86_64-freebsd-release (pull_request) Successful in 33m54s

Details

ci / x86_64-freebsd-debug (pull_request) Successful in 39m1s

Details

ci / x86_64-openbsd-release (pull_request) Successful in 43m52s

Details

ci / aarch64-macos-debug (pull_request) Successful in 49m23s

Details

ci / x86_64-openbsd-debug (pull_request) Successful in 55m30s

Details

ci / aarch64-linux-release (pull_request) Successful in 1h28m20s

Details

ci / x86_64-windows-debug (pull_request) Successful in 45m39s

Details

ci / x86_64-windows-release (pull_request) Successful in 45m25s

Details

ci / x86_64-linux-debug (pull_request) Successful in 1h20m17s

Details

ci / aarch64-linux-debug (pull_request) Successful in 2h24m25s

Details

ci / powerpc64le-linux-release (pull_request) Successful in 1h39m8s

Details

ci / x86_64-linux-debug-llvm (pull_request) Successful in 2h32m15s

Details

ci / x86_64-linux-release (pull_request) Successful in 2h25m11s

Details

ci / s390x-linux-release (pull_request) Successful in 2h2m18s

Details

ci / s390x-linux-debug (pull_request) Successful in 2h53m30s

Details

ci / powerpc64le-linux-debug (pull_request) Successful in 3h29m20s

Details

ci / loongarch64-linux-debug (pull_request) Successful in 2h52m1s

Details

ci / riscv64-linux-debug (pull_request) Has been skipped

Details

ci / riscv64-linux-release (pull_request) Has been skipped

Details

ci / loongarch64-linux-release (pull_request) Successful in 2h8m55s

Details

ebc17282b1

rpkak requested changes

2026年02月03日 18:59:22 +01:00

rpkak left a comment

Copy link

zig build test-libc -Dlibc-test-path=/path/to/libc-test -fqemu -fwasmtime -Dtest-filter=fmaf

fails on every tested architecture.

``` zig build test-libc -Dlibc-test-path=/path/to/libc-test -fqemu -fwasmtime -Dtest-filter=fmaf ``` fails on every tested architecture.

usebeforefree commented

2026年02月03日 23:34:22 +01:00

Author

First-time contributor

Copy link

Thanks, I ran the test command without -fqemu -fwasmtime and it worked, which was suspicious to me. I'll check it out tomorrow. The function itself is not complex, though I cannot seem to figure out how to trigger/check for a FE_UNDERFLOW bit. I saw that similar problems are handled with doNotOptimize triggering some bit, but didn't find any example for underflow. Tried this: std.mem.doNotOptimizeAway(0x1p-126 * 0x1p-126) though it either didn't work, or I have some other unknown problem. Anyways if it did work I am not sure how to confirm it works (the underflow bit). So I am kinda stuck atm.

The original func for context:

floatfmaf(floatx,floaty,floatz){#pragmaSTDCFENV_ACCESSONdoublexy,result;union{doublef;uint64_ti;}u;inte;xy=(double)x*y;result=xy+z;u.f=result;e=u.i>>52&0x7ff;/*Commoncase:Thedoubleprecisionresultisfine.*/if((u.i&0x1fffffff)!=0x10000000||/*notahalfwaycase*/e==0x7ff||/*NaN*/(result-xy==z&&result-z==xy)||/*exact*/fegetround()!=FE_TONEAREST)/*notround-to-nearest*/{/*underflowmaynotberaisedcorrectly,example:fmaf(0x1p-120f,0x1p-120f,0x1p-149f)*/#ifdefined(FE_INEXACT)&&defined(FE_UNDERFLOW)if(e<0x3ff-126&&e>=0x3ff-149&&fetestexcept(FE_INEXACT)){feclearexcept(FE_INEXACT);/*TODO:gccandclangbugworkaround*/volatilefloatvz=z;result=xy+vz;if(fetestexcept(FE_INEXACT))feraiseexcept(FE_UNDERFLOW);elseferaiseexcept(FE_INEXACT);}#endifz=result;returnz;}

Thanks, I ran the test command without `-fqemu -fwasmtime` and it worked, which was suspicious to me. I'll check it out tomorrow. The function itself is not complex, though I cannot seem to figure out how to trigger/check for a `FE_UNDERFLOW` bit. I saw that similar problems are handled with `doNotOptimize` triggering some bit, but didn't find any example for underflow. Tried this: `std.mem.doNotOptimizeAway(0x1p-126 * 0x1p-126)` though it either didn't work, or I have some other unknown problem. Anyways if it did work I am not sure how to confirm it works (the underflow bit). So I am kinda stuck atm. The original func for context: ```Zig float fmaf(float x, float y, float z) { #pragma STDC FENV_ACCESS ON double xy, result; union {double f; uint64_t i;} u; int e; xy = (double)x * y; result = xy + z; u.f = result; e = u.i>>52 & 0x7ff; /* Common case: The double precision result is fine. */ if ((u.i & 0x1fffffff) != 0x10000000 || /* not a halfway case */ e == 0x7ff || /* NaN */ (result - xy == z && result - z == xy) || /* exact */ fegetround() != FE_TONEAREST) /* not round-to-nearest */ { /* underflow may not be raised correctly, example: fmaf(0x1p-120f, 0x1p-120f, 0x1p-149f) */ #if defined(FE_INEXACT) && defined(FE_UNDERFLOW) if (e < 0x3ff-126 && e >= 0x3ff-149 && fetestexcept(FE_INEXACT)) { feclearexcept(FE_INEXACT); /* TODO: gcc and clang bug workaround */ volatile float vz = z; result = xy + vz; if (fetestexcept(FE_INEXACT)) feraiseexcept(FE_UNDERFLOW); else feraiseexcept(FE_INEXACT); } #endif z = result; return z; } ```

usebeforefree changed title from ~~(削除) libzigc: fmaf (削除ここまで)~~ to WIP: libzigc: fmaf

2026年02月03日 23:34:37 +01:00

usebeforefree closed this pull request

2026年02月07日 18:20:56 +01:00

Some checks are pending

ci / aarch64-macos-release (pull_request) Successful in 28m40s

Required

Details

ci / x86_64-freebsd-release (pull_request) Successful in 33m54s

Required

Details

ci / x86_64-freebsd-debug (pull_request) Successful in 39m1s

Required

Details

ci / x86_64-openbsd-release (pull_request) Successful in 43m52s

Required

Details

ci / aarch64-macos-debug (pull_request) Successful in 49m23s

Required

Details

ci / x86_64-openbsd-debug (pull_request) Successful in 55m30s

Required

Details

ci / aarch64-linux-release (pull_request) Successful in 1h28m20s

Required

Details

ci / x86_64-windows-debug (pull_request) Successful in 45m39s

Required

Details

ci / x86_64-windows-release (pull_request) Successful in 45m25s

Required

Details

ci / x86_64-linux-debug (pull_request) Successful in 1h20m17s

Required

Details

ci / aarch64-linux-debug (pull_request) Successful in 2h24m25s

Required

Details

ci / powerpc64le-linux-release (pull_request) Successful in 1h39m8s

Required

Details

ci / x86_64-linux-debug-llvm (pull_request) Successful in 2h32m15s

Required

Details

ci / x86_64-linux-release (pull_request) Successful in 2h25m11s

Required

Details

ci / s390x-linux-release (pull_request) Successful in 2h2m18s

Required

Details

ci / s390x-linux-debug (pull_request) Successful in 2h53m30s

Required

Details

ci / powerpc64le-linux-debug (pull_request) Successful in 3h29m20s

Required

Details

ci / loongarch64-linux-debug (pull_request) Successful in 2h52m1s

Details

ci / riscv64-linux-debug (pull_request) Has been skipped

Details

ci / riscv64-linux-release (pull_request) Has been skipped

Details

ci / loongarch64-linux-release (pull_request) Successful in 2h8m55s

Details

ci / x86_64-netbsd-debug (pull_request)

Required

ci / x86_64-netbsd-release (pull_request)

Required

Pull request closed

Please reopen this pull request to perform a merge.

Reviewers

No reviewers

rpkak

Labels

Clear labels

This proposal is planned.

The web application for interactive documentation and generation of its assets.

backend/c

The C backend outputs C source code.

backend/llvm

The LLVM backend outputs an LLVM bitcode module.

backend/self-hosted

The self-hosted backends produce machine code directly.

binutils

Zig's included binary utilities: zig ar, zig dlltool, zig lib, zig ranlib, zig objcopy, and zig rc.

breaking

Implementing this issue could cause existing code to no longer compile or have different behavior.

build system

The Zig build system - zig build, std.Build, the build runner, and package management.

debug info

docs

An issue with documentation, e.g. the language reference or standard library doc comments.

error message

This issue points out an error message that is unhelpful and should be improved.

frontend

Tokenization, parsing, AstGen, ZonGen, Sema, Legalize, and Liveness.

fuzzing

incremental

Reuse of internal compiler state for faster compilation.

lib/c

This issue relates to Zig's libc implementation and/or vendored libcs.

lib/compiler-rt

This issue relates to Zig's compiler-rt library.

lib/cxx

This issue relates to Zig's vendored libc++ and/or libc++abi.

lib/std

This issue relates to Zig's standard library.

lib/tsan

This issue relates to Zig's vendored libtsan.

lib/ubsan-rt

This issue relates to Zig's ubsan-rt library.

lib/unwind

This issue relates to Zig's vendored libunwind.

linking

Zig's integrated object file and incremental linker.

miscompilation

The compiler reports success but produces semantically incorrect code.

This issue suggests language modifications. If it also has the "accepted" label then it is planned.

release notes

This issue or pull request should be mentioned in the release notes.

testing

This issue is related to testing the compiler, standard library, or other parts of Zig.

zig cc

Zig as a drop-in C-family compiler.

zig fmt

The Zig source code formatter.

zig reduce

The Zig source code reduction tool.

bounty

https://ziglang.org/news/announcing-donor-bounties

bug

Observed behavior contradicts documented or intended behavior.

contributor-friendly

This issue is limited in scope and/or knowledge of project internals.

downstream

An issue with a third-party project that uses this project.

enhancement

Solving this issue will likely involve adding new logic or components to the codebase.

infra

optimization

A task to improve performance and/or resource usage.

question

No questions on the issue tracker; use a community space instead.

regression

Something that used to work in a previous version stopped working

upstream

An issue with a third-party project that this project uses.

use case

Describes a real use case that is difficult or impossible, but does not propose a solution.

No labels

Milestone

Clear milestone

No items

No milestone

Projects

Clear projects

No items

No project

Assignees

Clear assignees

No assignees

2 participants

Notifications

Due date

The due date is invalid or out of range. Please use the format "yyyy-mm-dd".

No due date set.

Dependencies

No dependencies set.

Reference

ziglang/zig!31105

No description provided.

Delete branch "usebeforefree/zig:libzigc-fmaf"

Deleting a branch is permanent. Although the deleted branch may continue to exist for a short time before it actually gets removed, it CANNOT be undone in most cases. Continue?