[Bug target/120986] ICE when expanding svdot_lane_fpm intrinsic with compile time know FPMR

[alfierichards at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=120986

--- Comment #2 from Alfie Richards <alfierichards at gcc dot gnu.org> ---
Final reproducer:

```c
#include <arm_sve.h>

svfloat16_t test (svfloat16_t a, svmfloat8_t b, svmfloat8_t c)
{
    return svdot_lane_fpm (a, b, c, 0, 0);
}
```

Compiled with `-O2 -march=armv8-a+sve2+fp8dot2`