jit: remove redundand unpack bfp format conversion

[iwroszTT]

Ticket

Link to Github Issue

Problem description

UNPACK src and dst data formats are selected during JIT in jit_build/data_format.cpp
As part of the format selection, for UNPACK destination all BFP formats are normalized to either Bfp8_b or Bfp8. According to tt-isa-docs, for all BFP data types UNPACK src and dst formats must be the same. As a result of that, the current code leads to undefined behavior and consequently to errors in tests on ttsim.

What's changed

BFP type normalization is removed, so that the generated UNPACK data formats are in line with the spec

Checklist

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• New/Existing tests provide coverage for changes

The failures in L2 nightly occur on main too

Model tests

If your changes cover model-related code, you should run tests corresponding to affected models and platforms (Single card, T3K, Galaxy). "Choose your pipeline" workflows facilitate running multiple kinds of tests in a single run. Each offers models-mandatory and models-extended presets.
The former includes a minimal set of tests, to be run always. The latter extends that with additional ones - use your best judgement in deciding which is the most appropriate for your PR.

• 

  • models-mandatory preset (runs: Device perf regressions and Frequent model and ttnn tests)
  • models-extended preset (runs: the mandatory tests, plus Demo and Model perf tests)
  • other selection - specify runs

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  • models-mandatory preset (runs: Unit tests)
  • models-extended preset (runs: the mandatory tests, plus Demo and Model perf tests)
  • other selection - specify runs

• 

  • models-mandatory preset (runs: Quick tests)
  • models-extended preset (runs: the mandatory tests, plus Demo and Model perf tests)
  • other selection - specify runs

[Copilot]

Pull request overview

This PR fixes a correctness issue in the JIT build system's data format selection for UNPACK operations. The change removes incorrect BFP (Block Floating Point) format normalization that was causing UNPACK source and destination formats to mismatch, violating the tt-isa specification and causing test failures on ttsim.

Changes:

• Removed BFP format normalization in get_single_unpack_dst_format() that was converting all BFP types to either Bfp8_b or Bfp8
• Ensures UNPACK operations now correctly use matching source and destination formats for BFP data types, as required by the hardware specification

[iwroszTT]

/codeowners ping

[tenstorrent-github-bot]

CodeOwners Group Analysis

This PR requires approval from one member of each of the following groups:

Summary: 1 pending groups, 0 approved groups

Group Information:

• ⏳ tt_metal/jit_build/ (Group) - Members: Almeet Bhullar, John Bauman, Kevin Stevens, Nathan Sidwell, Rui Zhang | Pending approval

  📁 Files owned by this group (1 files)

  • tt_metal/jit_build/data_format.cpp

Note: At least one approval from each group is sufficient.

[tenstorrent-github-bot]

Hi Kevin Stevens (@kstevensTT), Rui Zhang (@ruizhangTT), this PR jit: remove redundand unpack bfp format conversion by Izajasz Wrosz (@iwroszTT) needs your approval/review to merge this.