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explow.c (anti_adjust_stack_and_probe_stack_clash): Avoid probing the red zone for stack_clash_protection_final_dynamic_probe...

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* explow.c (anti_adjust_stack_and_probe_stack_clash): Avoid probing
	the red zone for stack_clash_protection_final_dynamic_probe targets
	when the total dynamic stack size is zero bytes.

From-SVN: r254753
This commit is contained in:
Jeff Law 2017-11-14 23:30:31 -07:00 committed by Jeff Law
parent 611a7c7e37
commit 2a6fc98713
2 changed files with 16 additions and 2 deletions
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4
gcc/ChangeLog
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@ -1,5 +1,9 @@
2017-11-14 Jeff Law <law@redhat.com>
* explow.c (anti_adjust_stack_and_probe_stack_clash): Avoid probing
the red zone for stack_clash_protection_final_dynamic_probe targets
when the total dynamic stack size is zero bytes.
* tree-ssa-threadupdate.c (thread_through_all_blocks): Thread
blocks is post order.

14
gcc/explow.c
View File

@ -1999,6 +1999,13 @@ anti_adjust_stack_and_probe_stack_clash (rtx size)
if (size != CONST0_RTX (Pmode)
&& targetm.stack_clash_protection_final_dynamic_probe (residual))
{
/* SIZE could be zero at runtime and in that case *sp could hold
live data. Furthermore, we don't want to probe into the red
zone.
Go ahead and just guard a probe at *sp on SIZE != 0 at runtime
if SIZE is not a compile time constant. */
/* Ideally we would just probe at *sp. However, if SIZE is not
a compile-time constant, but is zero at runtime, then *sp
might hold live data. So probe at *sp if we know that
@ -2011,9 +2018,12 @@ anti_adjust_stack_and_probe_stack_clash (rtx size)
}
else
{
emit_stack_probe (plus_constant (Pmode, stack_pointer_rtx,
-GET_MODE_SIZE (word_mode)));
rtx label = gen_label_rtx ();
emit_cmp_and_jump_insns (size, CONST0_RTX (GET_MODE (size)),
EQ, NULL_RTX, Pmode, 1, label);
emit_stack_probe (stack_pointer_rtx);
emit_insn (gen_blockage ());
emit_label (label);
}
}
}