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(movqi): In address reg case, if d0

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appears in the address, use d1 instead as intermediate reg.

From-SVN: r3797
This commit is contained in:
Richard Stallman 1993-03-20 06:54:26 +00:00
parent 14a8d07859
commit 2bb3413d31
1 changed files with 16 additions and 2 deletions
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18
gcc/config/m68k/m68k.md
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@ -931,10 +931,24 @@
/* Moving a byte into an address register is not possible. */
/* Use d0 as an intermediate, but don't clobber its contents. */
if (ADDRESS_REG_P (operands[0]) && GET_CODE (operands[1]) == MEM)
return \"exg %/d0,%0\;move%.b %1,%/d0\;exg %/d0,%0\";
{
/* If the address of operand 1 uses d0, choose d1 as intermediate. */
if (refers_to_regno_p (0, 1, operands[1], NULL_RTX))
return \"exg %/d1,%0\;move%.b %1,%/d1\;exg %/d1,%0\";
/* Otherwise d0 is usable.
(An effective address on the 68k can't use two d-regs.) */
else
return \"exg %/d0,%0\;move%.b %1,%/d0\;exg %/d0,%0\";
}
/* Likewise for moving from an address reg. */
if (ADDRESS_REG_P (operands[1]) && GET_CODE (operands[0]) == MEM)
return \"exg %/d0,%1\;move%.b %/d0,%0\;exg %/d0,%1\";
{
if (refers_to_regno_p (0, 1, operands[0], NULL_RTX))
return \"exg %/d1,%1\;move%.b %/d1,%0\;exg %/d1,%1\";
else
return \"exg %/d0,%1\;move%.b %/d0,%0\;exg %/d0,%1\";
}
/* clr and st insns on 68000 read before writing.
This isn't so on the 68010, but we have no alternative for it. */