[Bug target/63408] [4.9/5/6 regression] GCC emits incorrect fixed->fp conversion instruction on Cortex-M4 target

[itay at phobotic dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63408

--- Comment #10 from Itay Perl <itay at phobotic dot com> ---
A few examples:

a=100, b=0x7fffffff          -O0: 0.0   -O3: 200.0
a=0,   b=0x7fffffff/100.0f   -O0: -1.0  -O3: 1.0
a=0,   b=-0x7fffffff/100.0f  -O0: 1.0   -O3: -1.0

Replacing vfma with vfms sounds correct to me, and returns the correct result
for the above inputs.