| Issue |
166949
|
| Summary |
[X86] Make VBMI2 supported ISD::FSHL/FSHR instructions legal instead of custom
|
| Labels |
good first issue,
backend:X86
|
| Assignees |
|
| Reporter |
RKSimon
|
FSHL/FSHR instructions are legal on VBMI2 targets for v32i16 / v16i32 / v8i64 types
FSHL/FSHR instructions are legal on VBMI2 + VLX targets for v8i16 / v16i16 / v4i32 / v8i32 / v2i64 / v4i64 types
There's no need to go through LowerFunnelShift for these cases, instead we should make them legal and add a combineFunnelShift to convert instructions with uniform constant shift amounts to use X86ISD::VSHLD/X86ISD::VSHRD.
We'll still need LowerFunnelShift to handle widening to 512-bits for VBMI2 only (no VLX) - but the constant handling can be moved entirely to the combine.
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