(x86) Initialize non-default floating-point rounding precision mode.
Sets the floating-point precision mode to either single, double, or extended on x86 platforms.
With a value of single or double, this flag causes the rounding precision mode to be set to single or double precision respectively at program initiation. With extended, or by default when the -fprecision flag is not specified, the rounding precision mode is initialized to extended precision.
This option is effective only on x86 systems and only if used when compiling the main program, but is ignored if compiling for 64–bit (-m64) or SSE2–enabled (-xarch=sse2) processors. It is also ignored on SPARC systems.