static rtx
maybe_mode_change (enum machine_mode orig_mode, enum machine_mode copy_mode,
enum machine_mode new_mode, unsigned int regno,
unsigned int copy_regno ATTRIBUTE_UNUSED)
{
if (GET_MODE_SIZE (copy_mode) < GET_MODE_SIZE (orig_mode)
&& GET_MODE_SIZE (copy_mode) < GET_MODE_SIZE (new_mode))
return NULL_RTX;
if (orig_mode == new_mode)
return gen_rtx_raw_REG (new_mode, regno);
else if (mode_change_ok (orig_mode, new_mode, regno))
{
int copy_nregs = hard_regno_nregs[copy_regno][copy_mode];
int use_nregs = hard_regno_nregs[copy_regno][new_mode];
int copy_offset
= GET_MODE_SIZE (copy_mode) / copy_nregs * (copy_nregs - use_nregs);
int offset
= GET_MODE_SIZE (orig_mode) - GET_MODE_SIZE (new_mode) - copy_offset;
int byteoffset = offset % UNITS_PER_WORD;
int wordoffset = offset - byteoffset;
offset = ((WORDS_BIG_ENDIAN ? wordoffset : 0)
+ (BYTES_BIG_ENDIAN ? byteoffset : 0));
regno += subreg_regno_offset (regno, orig_mode, offset, new_mode);
if (HARD_REGNO_MODE_OK (regno, new_mode))
return gen_rtx_raw_REG (new_mode, regno);
}
return NULL_RTX;
}
/// ValidateRegisterVariable - Check that a static "asm" variable is
/// well-formed. If not, emit error messages and return true. If so, return
/// false.
bool ValidateRegisterVariable(tree decl) {
const char *Name = IDENTIFIER_POINTER(DECL_ASSEMBLER_NAME(decl));
int RegNumber = decode_reg_name(Name);
const Type *Ty = ConvertType(TREE_TYPE(decl));
// If this has already been processed, don't emit duplicate error messages.
if (DECL_LLVM_SET_P(decl)) {
// Error state encoded into DECL_LLVM.
return cast<ConstantInt>(DECL_LLVM(decl))->getZExtValue();
}
/* Detect errors in declaring global registers. */
if (RegNumber == -1)
error("%Jregister name not specified for %qD", decl, decl);
else if (RegNumber < 0)
error("%Jinvalid register name for %qD", decl, decl);
else if (TYPE_MODE(TREE_TYPE(decl)) == BLKmode)
error("%Jdata type of %qD isn%'t suitable for a register", decl, decl);
#if 0 // FIXME: enable this.
else if (!HARD_REGNO_MODE_OK(RegNumber, TYPE_MODE(TREE_TYPE(decl))))
error("%Jregister specified for %qD isn%'t suitable for data type",
decl, decl);
#endif
else if (DECL_INITIAL(decl) != 0 && TREE_STATIC(decl))
error("global register variable has initial value");
else if (!Ty->isFirstClassType())
sorry("%JLLVM cannot handle register variable %qD, report a bug",
decl, decl);
else {
if (TREE_THIS_VOLATILE(decl))
warning("volatile register variables don%'t work as you might wish");
SET_DECL_LLVM(decl, ConstantInt::getFalse());
return false; // Everything ok.
}
SET_DECL_LLVM(decl, ConstantInt::getTrue());
return true;
}