[stinkytofu] Implement legalizeImplicitSpecialRegisters function

[pschang-phy]

Motivation

Implicit registers, eg. SCC, VCC, and EXEC must be attached to instruction's src/dest list so the def-use chain builder sees those dependencies. Today this only happens in the rocisa → stinkytofu converter, so any StinkyInstruction created via another path — most notably stinkytofu-opt parsing assembly text, but also instructions created inside legalization passes — is missing its implicit special registers.

Technical Details

• Extracted the logic into a shared helper legalizeImplicitSpecialRegisters(StinkyInstruction*, uint32_t wavefrontSize) in LegalizationUtils.{hpp,cpp}.
• ToStinkyTofuUtils.cpp now calls the helper instead of the inline if-chain — behavior unchanged for the rocisa path.
• StinkyBuildImplicitDependencyPass runs the helper on every instruction in every basic block, in addition to its existing LDS/MemTokenData handling.
• Result: stinkytofu-opt (and any other pipeline that builds IR outside the rocisa converter) gets correct implicit SCC/VCC/EXEC operands by simply adding StinkyBuildImplicitDependencyPass.

Test Plan

Test Result

Submission Checklist

• Look over the contributing guidelines at https://github.com/ROCm/ROCm/blob/develop/CONTRIBUTING.md#pull-requests.

[cycheng]

LGTM, few notes.

[darrenhsieh-amd]

LGTM

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.

❌ Your project status has failed because the head coverage (69.24%) is below the target coverage (80.00%). You can increase the head coverage or adjust the target coverage.

Additional details and impacted files

@@           Coverage Diff            @@
##           develop    #7268   +/-   ##
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  Coverage    64.36%   64.36%           
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  Files          603      603           
  Lines       112196   112196           
  Branches     15498    15498           
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  Hits         72205    72205           
  Misses       34724    34724           
  Partials      5267     5267           

Flag	Coverage Δ		*Carryforward flag
hipBLASLt	39.85% <ø> (ø)
hipDNN	85.56% <ø> (ø)		Carriedforward from 171d97b
hipFFT	49.22% <ø> (ø)		Carriedforward from 171d97b
hipSOLVER	69.24% <ø> (ø)		Carriedforward from 171d97b
rocFFT	47.60% <ø> (ø)		Carriedforward from 171d97b
rocRAND	57.02% <ø> (ø)		Carriedforward from 171d97b

*This pull request uses carry forward flags. Click here to find out more.

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