rust-lang / rust-lang/rustc_codegen_cranelift
Unimplemented x86 llvm intrinsic vcvtph2ps
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Description
When compiling half I noticed two warnings for a missing x86 llvm intrinsic vcvtph2ps:
warning: unsupported x86 llvm intrinsic llvm.x86.vcvtph2ps.128; replacing with trap
warning: unsupported x86 llvm intrinsic llvm.x86.vcvtph2ps.256; replacing with trap
trap at Instance { def: Item(DefId(2:23219 ~ core[4322]::core_arch::x86::f16c::_mm_cvtps_ph)), args: [0_i32] } (_ZN4core9core_arch3x864f16c12_mm_cvtps_ph17heb7efe16215ebb1fE): llvm.x86.vcvtps2ph.128
Thanks for all your work on the cranelift backend for rust!
Edit: I guess this is might be related to https://github.com/rust-lang/rustc_codegen_cranelift/issues/1461
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- Read the whole issue, then the project's contributing guide.
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Research direction
Start by reproducing the warnings from the half crate and trace the core_arch x86 f16c entry point _mm_cvtps_ph to the llvm.x86.vcvtph2ps.128 and .256 intrinsics. Compare this issue with related issue #1461. Done means both intrinsics compile without warnings or trap replacement and the relevant half-crate path works.
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Assessment
- Tech stack
- rust
- Domain
- compilers
- Issue type
- Bug
- Difficulty
- 4/5
- Estimated time
- 3-5 days
- Activity status
- Stale
- Clarity
- Mostly clear
- Newbie friendliness
- 42/100