/* Combine stack adjustments.
- Copyright (C) 1987-2014 Free Software Foundation, Inc.
+ Copyright (C) 1987-2019 Free Software Foundation, Inc.
This file is part of GCC.
#include "config.h"
#include "system.h"
#include "coretypes.h"
-#include "tm.h"
+#include "backend.h"
#include "rtl.h"
-#include "tm_p.h"
+#include "df.h"
#include "insn-config.h"
+#include "memmodel.h"
+#include "emit-rtl.h"
#include "recog.h"
-#include "regs.h"
-#include "hard-reg-set.h"
-#include "flags.h"
-#include "function.h"
-#include "expr.h"
-#include "basic-block.h"
-#include "df.h"
-#include "except.h"
-#include "reload.h"
+#include "cfgrtl.h"
#include "tree-pass.h"
#include "rtl-iter.h"
\f
-/* Turn STACK_GROWS_DOWNWARD into a boolean. */
-#ifdef STACK_GROWS_DOWNWARD
-#undef STACK_GROWS_DOWNWARD
-#define STACK_GROWS_DOWNWARD 1
-#else
-#define STACK_GROWS_DOWNWARD 0
-#endif
-
/* This structure records two kinds of stack references between stack
adjusting instructions: stack references in memory addresses for
regular insns and all stack references for debug insns. */
return ml;
}
+/* We only know how to adjust the CFA; no other frame-related changes
+ may appear in any insn to be deleted. */
+
+static bool
+no_unhandled_cfa (rtx_insn *insn)
+{
+ if (!RTX_FRAME_RELATED_P (insn))
+ return true;
+
+ /* No CFA notes at all is a legacy interpretation like
+ FRAME_RELATED_EXPR, and is context sensitive within
+ the prologue state machine. We can't handle that here. */
+ bool has_cfa_adjust = false;
+
+ for (rtx link = REG_NOTES (insn); link; link = XEXP (link, 1))
+ switch (REG_NOTE_KIND (link))
+ {
+ default:
+ break;
+ case REG_CFA_ADJUST_CFA:
+ has_cfa_adjust = true;
+ break;
+
+ case REG_FRAME_RELATED_EXPR:
+ case REG_CFA_DEF_CFA:
+ case REG_CFA_OFFSET:
+ case REG_CFA_REGISTER:
+ case REG_CFA_EXPRESSION:
+ case REG_CFA_RESTORE:
+ case REG_CFA_SET_VDRAP:
+ case REG_CFA_WINDOW_SAVE:
+ case REG_CFA_FLUSH_QUEUE:
+ case REG_CFA_TOGGLE_RA_MANGLE:
+ return false;
+ }
+
+ return has_cfa_adjust;
+}
+
/* Attempt to apply ADJUST to the stack adjusting insn INSN, as well
as each of the memories and stack references in REFLIST. Return true
on success. */
add_reg_note (last, REG_ARGS_SIZE, XEXP (note, 0));
}
+/* Merge any REG_CFA_ADJUST_CFA note from SRC into DST.
+ AFTER is true iff DST follows SRC in the instruction stream. */
+
+static void
+maybe_merge_cfa_adjust (rtx_insn *dst, rtx_insn *src, bool after)
+{
+ rtx snote = NULL, dnote = NULL;
+ rtx sexp, dexp;
+ rtx exp1, exp2;
+
+ if (RTX_FRAME_RELATED_P (src))
+ snote = find_reg_note (src, REG_CFA_ADJUST_CFA, NULL_RTX);
+ if (snote == NULL)
+ return;
+ sexp = XEXP (snote, 0);
+
+ if (RTX_FRAME_RELATED_P (dst))
+ dnote = find_reg_note (dst, REG_CFA_ADJUST_CFA, NULL_RTX);
+ if (dnote == NULL)
+ {
+ add_reg_note (dst, REG_CFA_ADJUST_CFA, sexp);
+ return;
+ }
+ dexp = XEXP (dnote, 0);
+
+ gcc_assert (GET_CODE (sexp) == SET);
+ gcc_assert (GET_CODE (dexp) == SET);
+
+ if (after)
+ exp1 = dexp, exp2 = sexp;
+ else
+ exp1 = sexp, exp2 = dexp;
+
+ SET_SRC (exp1) = simplify_replace_rtx (SET_SRC (exp1), SET_DEST (exp2),
+ SET_SRC (exp2));
+ XEXP (dnote, 0) = exp1;
+}
+
/* Return the next (or previous) active insn within BB. */
static rtx_insn *
continue;
set = single_set_for_csa (insn);
+ if (set && find_reg_note (insn, REG_STACK_CHECK, NULL_RTX))
+ set = NULL_RTX;
if (set)
{
rtx dest = SET_DEST (set);
Also we need to be careful to not move stack pointer
such that we create stack accesses outside the allocated
area. We can combine an allocation into the first insn,
- or a deallocation into the second insn. We can not
+ or a deallocation into the second insn. We cannot
combine an allocation followed by a deallocation.
The only somewhat frequent occurrence of the later is when
/* Combine an allocation into the first instruction. */
if (STACK_GROWS_DOWNWARD ? this_adjust <= 0 : this_adjust >= 0)
{
- if (try_apply_stack_adjustment (last_sp_set, reflist,
- last_sp_adjust + this_adjust,
- this_adjust))
+ if (no_unhandled_cfa (insn)
+ && try_apply_stack_adjustment (last_sp_set, reflist,
+ last_sp_adjust
+ + this_adjust,
+ this_adjust))
{
/* It worked! */
maybe_move_args_size_note (last_sp_set, insn, false);
+ maybe_merge_cfa_adjust (last_sp_set, insn, false);
delete_insn (insn);
last_sp_adjust += this_adjust;
continue;
else if (STACK_GROWS_DOWNWARD
? last_sp_adjust >= 0 : last_sp_adjust <= 0)
{
- if (try_apply_stack_adjustment (insn, reflist,
- last_sp_adjust + this_adjust,
- -last_sp_adjust))
+ if (no_unhandled_cfa (last_sp_set)
+ && try_apply_stack_adjustment (insn, reflist,
+ last_sp_adjust
+ + this_adjust,
+ -last_sp_adjust))
{
/* It worked! */
maybe_move_args_size_note (insn, last_sp_set, true);
+ maybe_merge_cfa_adjust (insn, last_sp_set, true);
delete_insn (last_sp_set);
last_sp_set = insn;
last_sp_adjust += this_adjust;
delete the old deallocation insn. */
if (last_sp_set)
{
- if (last_sp_adjust == 0)
+ if (last_sp_adjust == 0 && no_unhandled_cfa (last_sp_set))
{
maybe_move_args_size_note (insn, last_sp_set, true);
+ maybe_merge_cfa_adjust (insn, last_sp_set, true);
delete_insn (last_sp_set);
}
else
if (MEM_P (dest)
&& ((STACK_GROWS_DOWNWARD
? (GET_CODE (XEXP (dest, 0)) == PRE_DEC
- && last_sp_adjust
- == (HOST_WIDE_INT) GET_MODE_SIZE (GET_MODE (dest)))
+ && known_eq (last_sp_adjust,
+ GET_MODE_SIZE (GET_MODE (dest))))
: (GET_CODE (XEXP (dest, 0)) == PRE_INC
- && last_sp_adjust
- == -(HOST_WIDE_INT) GET_MODE_SIZE (GET_MODE (dest))))
+ && known_eq (-last_sp_adjust,
+ GET_MODE_SIZE (GET_MODE (dest)))))
|| ((STACK_GROWS_DOWNWARD
? last_sp_adjust >= 0 : last_sp_adjust <= 0)
&& GET_CODE (XEXP (dest, 0)) == PRE_MODIFY
projects / gcc.git / blobdiff