[LLVMdev] __float128 (f128) calling convention bug on x86_64

[Chih-hung Hsieh]

Hello, I'm new to this mailing list and fixing llvm bugs for Android.

Can anyone point me to any previous discussion or work related to the
following bug?
  https://llvm.org/bugs/show_bug.cgi?id=23897

I am testing my patch to llvm to make f128 values stay in SSE registers
instead of being split into two i64 values. I have tried to add a register
class FR128 to hold f128 values for the x86_64 target. Preliminary tests
seem to be working and compatible with gcc's __float128 long double type.

I found that long double complex (with two f128 values) also have calling
convention compatibility problem with gcc and can be fixed similarly.
My current patch does change quite a few places in type legalizing pass and
some other optimizations related to f128 or i128 values. A few changes in
the softening of floating point types to keep some f128 typed IR and
convert some f128 opcode to library function calls.

Has anyone tried this approach or have other solution?

Thanks

-- Chih-Hung
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