+2002-08-14 Dale Johannesen <dalej@apple.com>
+
+ * explow.c (emit_stack_restore): Emit memory clobbers
+ preceding the stack pop, to prevent the scheduler from
+ moving refs to variable arrays below this pop.
+ * reload1.c (reload): Preserve these clobbers for sched2.
+ * doc/rtl.texi: Document clobber (mem:BLK (scratch)).
+
2002-08-14 Neil Booth <neil@daikokuya.co.uk>
* c-opts.c (c_common_post_options): Correct test.
inform the compiler that the registers will be altered, lest it
attempt to keep data in them across the string instruction.
-If @var{x} is @code{(mem:BLK (const_int 0))}, it means that all memory
+If @var{x} is @code{(mem:BLK (const_int 0))} or
+@code{(mem:BLK (scratch))}, it means that all memory
locations must be presumed clobbered. If @var{x} is a @code{parallel},
it has the same meaning as a @code{parallel} in a @code{set} expression.
}
if (sa != 0)
- sa = validize_mem (sa);
+ {
+ sa = validize_mem (sa);
+ /* These clobbers prevent the scheduler from moving
+ references to variable arrays below the code
+ that deletes (pops) the arrays. */
+ emit_insn (gen_rtx_CLOBBER (VOIDmode,
+ gen_rtx_MEM (BLKmode,
+ gen_rtx_SCRATCH (VOIDmode))));
+ emit_insn (gen_rtx_CLOBBER (VOIDmode,
+ gen_rtx_MEM (BLKmode, stack_pointer_rtx)));
+ }
if (after)
{
/* Make a pass over all the insns and delete all USEs which we inserted
only to tag a REG_EQUAL note on them. Remove all REG_DEAD and REG_UNUSED
notes. Delete all CLOBBER insns that don't refer to the return value
- and simplify (subreg (reg)) operands. Also remove all REG_RETVAL and
- REG_LIBCALL notes since they are no longer useful or accurate. Strip
- and regenerate REG_INC notes that may have been moved around. */
+ or to memory (mem:BLK CLOBBERs must be retained to prevent the scheduler
+ from misarranging variable-array code) and simplify (subreg (reg))
+ operands. Also remove all REG_RETVAL and REG_LIBCALL notes since they
+ are no longer useful or accurate. Strip and regenerate REG_INC notes
+ that may have been moved around. */
for (insn = first; insn; insn = NEXT_INSN (insn))
if (INSN_P (insn))
&& (GET_MODE (insn) == QImode
|| find_reg_note (insn, REG_EQUAL, NULL_RTX)))
|| (GET_CODE (PATTERN (insn)) == CLOBBER
+ && (GET_CODE (XEXP (PATTERN (insn), 0)) != MEM
+ || GET_MODE (XEXP (PATTERN (insn), 0)) != BLKmode)
&& (GET_CODE (XEXP (PATTERN (insn), 0)) != REG
|| ! REG_FUNCTION_VALUE_P (XEXP (PATTERN (insn), 0)))))
{