Hi!
As the patch I've just posted is probably too dangerous for 7.1, here
is a more localized version of the fix, which doesn't change reg_set_p/
modified_in_p/modified_between_p etc. behavior that is used in many spots,
but just changes emit_swap_insn that has seen that problem (this code in
emit_swap_insn is new in 7, so it is a P1 wrong-code regression).
What the patch does is instead of relying on modified_between_p to catch
this it checks whether i1src is sp based and if it is, checks the insns
while skipping over them whether they are push/pop (autoinc of sp) and
if so, punts.
Bootstrapped/regtested on x86_64-linux and i686-linux, ok for 7.1?
2017-04-27 Jakub Jelinek <ja...@redhat.com>
PR target/79430
* reg-stack.c (emit_swap_insn): If i1src mentions the stack pointer,
punt if tmp contains autoinc of stack pointer.
--- gcc/reg-stack.c.jj 2017-04-26 10:13:49.000000000 +0200
+++ gcc/reg-stack.c 2017-04-26 13:13:19.487471078 +0200
@@ -915,6 +915,7 @@ emit_swap_insn (rtx_insn *insn, stack_pt
rtx i2set;
rtx_insn *tmp = PREV_INSN (i1);
rtx_insn *limit = PREV_INSN (BB_HEAD (current_block));
+ bool sp_used = reg_overlap_mentioned_p (stack_pointer_rtx, i1src);
/* Find the previous insn involving stack regs, but don't pass a
block boundary. */
while (tmp != limit)
@@ -928,6 +929,31 @@ emit_swap_insn (rtx_insn *insn, stack_pt
i2 = tmp;
break;
}
+ /* FIXME: modified_between_p does not consider autoinc
+ modifications of stack pointer if i1src refers to
+ stack pointer, check it here manually. */
+ if (sp_used && NONDEBUG_INSN_P (tmp))
+ {
+ subrtx_var_iterator::array_type array;
+ FOR_EACH_SUBRTX_VAR (iter, array, PATTERN (tmp), NONCONST)
+ {
+ rtx mem = *iter;
+ if (mem
+ && MEM_P (mem)
+ && (GET_RTX_CLASS (GET_CODE (XEXP (mem, 0)))
+ == RTX_AUTOINC))
+ {
+ if (XEXP (XEXP (mem, 0), 0) == stack_pointer_rtx)
+ {
+ i2 = tmp;
+ break;
+ }
+ iter.skip_subrtxes ();
+ }
+ }
+ if (i2)
+ break;
+ }
tmp = PREV_INSN (tmp);
}
if (i2 != NULL_RTX
Jakub
