[AMDGPU] Make direct f16 <-> i32 conversion illegal (#205565)
Neither SALU nor VALU support direct conversion from f16 to/from i32.
Previously, this was still legal and handled by instruction selection
patterns, forming chains f16 -> f32 -> i32 and i32 -> f32 -> f16 for the
two cases, respectively.
This change marks the conversion illegal and creates the same chains as
the pattern during (operation) legalization.
This had the added benefit that a combination of FNEG and FPTOSI/UI can
now merge the float negation into the source modifier of the f16-to-f32
conversion, as demonstrated by the GlobalISel tests.
This fixes https://github.com/llvm/llvm-project/issues/177342.
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Signed-off-by: Lukas Sommer <lukas.sommer@amd.com>
llvm-project
1375ac20 - [AMDGPU] Make direct f16 <-> i32 conversion illegal (#205565)
