r366480 - [RISCV] Hard float ABI support

[Hans Wennborg via cfe-commits]

Merged to the 9.0 branch in r366554.

On Thu, Jul 18, 2019 at 8:29 PM Alex Bradbury via cfe-commits
<cfe-commits at lists.llvm.org> wrote:
>
> Author: asb
> Date: Thu Jul 18 11:29:59 2019
> New Revision: 366480
>
> URL: http://llvm.org/viewvc/llvm-project?rev=366480&view=rev
> Log:
> [RISCV] Hard float ABI support
>
> The RISC-V hard float calling convention requires the frontend to:
>
> * Detect cases where, once "flattened", a struct can be passed using
> int+fp or fp+fp registers under the hard float ABI and coerce to the
> appropriate type(s)
> * Track usage of GPRs and FPRs in order to gate the above, and to
> determine when signext/zeroext attributes must be added to integer
> scalars
>
> This patch attempts to do this in compliance with the documented ABI,
> and uses ABIArgInfo::CoerceAndExpand in order to do this. @rjmccall, as
> author of that code I've tagged you as reviewer for initial feedback on
> my usage.
>
> Note that a previous version of the ABI indicated that when passing an
> int+fp struct using a GPR+FPR, the int would need to be sign or
> zero-extended appropriately. GCC never did this and the ABI was changed,
> which makes life easier as ABIArgInfo::CoerceAndExpand can't currently
> handle sign/zero-extension attributes.
>
> Re-landed after backing out 366450 due to missed hunks.
>
> Differential Revision: https://reviews.llvm.org/D60456
>
> Added:
>     cfe/trunk/test/CodeGen/riscv32-ilp32d-abi.c
>     cfe/trunk/test/CodeGen/riscv32-ilp32f-abi.c
>     cfe/trunk/test/CodeGen/riscv32-ilp32f-ilp32d-abi.c
>     cfe/trunk/test/CodeGen/riscv64-lp64d-abi.c
>     cfe/trunk/test/CodeGen/riscv64-lp64f-lp64d-abi.c
> Modified:
>     cfe/trunk/lib/Basic/Targets/RISCV.cpp
>     cfe/trunk/lib/Basic/Targets/RISCV.h
>     cfe/trunk/lib/CodeGen/TargetInfo.cpp
>     cfe/trunk/test/CodeGen/riscv32-ilp32-ilp32f-abi.c
>     cfe/trunk/test/CodeGen/riscv32-ilp32-ilp32f-ilp32d-abi.c
>     cfe/trunk/test/CodeGen/riscv64-lp64-lp64f-abi.c
>     cfe/trunk/test/CodeGen/riscv64-lp64-lp64f-lp64d-abi.c
>     cfe/trunk/test/Driver/riscv-abi.c
>     cfe/trunk/test/Preprocessor/riscv-target-features.c