3.17.18 SH Options
These `-m' options are defined for the SH implementations:
     
-m1- Generate code for the SH1.
     
 -m2- Generate code for the SH2.
     
 -m2e- Generate code for the SH2e.
     
 -m3- Generate code for the SH3.
     
 -m3e- Generate code for the SH3e.
     
 -m4-nofpu- Generate code for the SH4 without a floating-point unit.
     
 -m4-single-only- Generate code for the SH4 with a floating-point unit that only
supports single-precision arithmetic.
     
 -m4-single- Generate code for the SH4 assuming the floating-point unit is in
single-precision mode by default.
     
 -m4- Generate code for the SH4.
     
 -mb- Compile code for the processor in big endian mode.
     
 -ml- Compile code for the processor in little endian mode.
     
 -mdalign- Align doubles at 64-bit boundaries.  Note that this changes the calling
conventions, and thus some functions from the standard C library will
not work unless you recompile it first with -mdalign.
     
 -mrelax- Shorten some address references at link time, when possible; uses the
linker option -relax.
     
 -mbigtable- Use 32-bit offsets in 
switch tables.  The default is to use
16-bit offsets.
     
 -mfmovd- Enable the use of the instruction 
fmovd.
     
 -mhitachi- Comply with the calling conventions defined by Renesas.
     
 -mnomacsave- Mark the 
MAC register as call-clobbered, even if
-mhitachi is given.
     
 -mieee- Increase IEEE-compliance of floating-point code.
     
 -misize- Dump instruction size and location in the assembly code.
     
 -mpadstruct- This option is deprecated.  It pads structures to multiple of 4 bytes,
which is incompatible with the SH ABI.
     
 -mspace- Optimize for space instead of speed.  Implied by -Os.
     
 -mprefergot- When generating position-independent code, emit function calls using
the Global Offset Table instead of the Procedure Linkage Table.
     
 -musermode- Generate a library function call to invalidate instruction cache
entries, after fixing up a trampoline.  This library function call
doesn't assume it can write to the whole memory address space.  This
is the default when the target is 
sh-*-linux*.