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[GSoC-19] Expanding fromfp variants on AArch64
- From: Tejas Joshi <tejasjoshi9673 at gmail dot com>
- To: gcc at gcc dot gnu dot org
- Cc: Martin Jambor <mjambor at suse dot cz>, hubicka at ucw dot cz, joseph at codesourcery dot com
- Date: Mon, 19 Aug 2019 16:37:29 +0530
- Subject: [GSoC-19] Expanding fromfp variants on AArch64
Hello.
The fromfp/fromfpx variants round to integers with a specified number
of bits, to a specified rounding mode. They come with their own
complications as Joseph had stated in an initial mail and expected to
expand them in AArch64 :
> The fromfp / fromfpx / ufromfp / ufromfpx functions (round to integers
> of a specified number of bits, in a specified rounding mode, with
> specified handling of inexact results) are a case with some other
> complications. Typically I'd expect them to be expanded inline only (for
> constant arguments or) for constant values of the number of bits and
> rounding mode, if the target machine has an appropriate instruction. A
> target hook would need adding for a target to specify the FP_INT_* values
> used in libm, since that's an ABI that's defined by libm, not by GCC.
> Then you'd need instruction patterns that might only be supported in
> certain cases.
How can I add a target hook to specify the FP_INT_* values from libm ?
Also as this includes rounding to integers, does it involve any RTL
related complications that we have encountered in FADD ?
Thanks,
Tejas