The RISC-V implementations of the `__mulsi3`, `__muldi3` builtins were
conditionally compiling the actual function definitions depending on whether
the M extension was present or not. This caused Compiler-RT testing failures
for RISC-V targets with the M extension, as when these sources were included
the `librt_has_mul*i3` features were still being defined. These `librt_has_*`
definitions are used to conditionally run the respective tests. Since the
actual functions were not being compiled-in, the generic test for `__muldi3`
would fail. This patch makes these implementations follow the normal
Compiler-RT convention of always including the definition, and conditionally
running the respective tests by using the lit conditional
`REQUIRES: librt_has_*`.
Since the `mulsi3_test.c` wasn't actually RISC-V-specific, this patch also
moves it out of the `riscv` directory. It now only depends on
`librt_has_mulsi3` to run.
Differential Revision: https://reviews.llvm.org/D86457
Luís Marques