- Enable s_or_b64/s_and_b64/s_xor_b64 for v2i32. Add various additional
combines to make use of these newly legalised instructions.
- Update several tests and separate legacy r600 tests where necessary.
The Target hook convertSelectOfConstantsToMath() needs to be used within
SimplifySelectCC helper combine function in SelectionDAG Isel, where
generic select folding with constants is happening into simple maths op
using the condition as it is.
It necessarily fixes#121145.
The materialization cost of 32-bit non-inline in case of fmul is quite
relatively more, rather than if possible to combine it into ldexp
instruction for specific scenarios (for datatypes like f64, f32 and f16)
as this is being handled here :
The dag combine for any pair of select values which are exact exponent
of 2.
```
fmul x, select(y, A, B) -> ldexp (x, select i32 (y, a, b))
fmul x, select(y, -A, -B) -> ldexp ((fneg x), select i32 (y, a, b))
where, A=2^a & B=2^b ; a and b are integers.
```
This dagCombine is handled separately in fmulCombine (newly defined in
SIIselLowering), targeting fmul fusing it with select type operand into
ldexp.
Thus, it fixes#104900.
Math library code has quite a few places with complex bit
logic that are ultimately fed into a copysign. This helps
avoid some regressions in a future patch.
This assumes the position in the float type, which should
at least be valid for IEEE types. Not sure if we need to guard
against ppc_fp128 or anything else weird.
There appears to be some value in simplifying the value operand
as well, but I'll address that separately.
