diff options
Diffstat (limited to 'gcc/config/i386/i386.h')
| -rw-r--r-- | gcc/config/i386/i386.h | 14 |
1 files changed, 14 insertions, 0 deletions
diff --git a/gcc/config/i386/i386.h b/gcc/config/i386/i386.h index 1e38d10d36e..e46a19f6b30 100644 --- a/gcc/config/i386/i386.h +++ b/gcc/config/i386/i386.h @@ -1558,6 +1558,20 @@ enum reg_class || ((CLASS) == SIREG) \ || ((CLASS) == DIREG)) +/* Return a class of registers that cannot change FROM mode to TO mode. + + x87 registers can't do subreg as all values are reformated to extended + precision. XMM registers does not support with nonzero offsets equal + to 4, 8 and 12 otherwise valid for integer registers. Since we can't + determine these, prohibit all nonparadoxical subregs changing size. */ + +#define CANNOT_CHANGE_MODE_CLASS(FROM, TO, CLASS) \ + (GET_MODE_SIZE (TO) < GET_MODE_SIZE (FROM) \ + ? reg_classes_intersect_p (FLOAT_SSE_REGS, (CLASS)) \ + || MAYBE_MMX_CLASS_P (CLASS) \ + : GET_MODE_SIZE (FROM) != GET_MODE_SIZE (TO) \ + ? reg_classes_intersect_p (FLOAT_REGS, (CLASS)) : 0) + /* A C statement that adds to CLOBBERS any hard regs the port wishes to automatically clobber for all asms. |
