/* RTL dead code elimination.
- Copyright (C) 2005, 2006, 2007, 2008, 2009 Free Software Foundation, Inc.
+ Copyright (C) 2005, 2006, 2007, 2008, 2009, 2010, 2011
+ Free Software Foundation, Inc.
This file is part of GCC.
}
+/* Return true if store to MEM, starting OFF bytes from stack pointer,
+ is a call argument store, and clear corresponding bits from SP_BYTES
+ bitmap if it is. */
+
+static bool
+check_argument_store (rtx mem, HOST_WIDE_INT off, HOST_WIDE_INT min_sp_off,
+ HOST_WIDE_INT max_sp_off, bitmap sp_bytes)
+{
+ HOST_WIDE_INT byte;
+ for (byte = off; byte < off + GET_MODE_SIZE (GET_MODE (mem)); byte++)
+ {
+ if (byte < min_sp_off
+ || byte >= max_sp_off
+ || !bitmap_clear_bit (sp_bytes, byte - min_sp_off))
+ return false;
+ }
+ return true;
+}
+
+
/* Try to find all stack stores of CALL_INSN arguments if
ACCUMULATE_OUTGOING_ARGS. If all stack stores have been found
and it is therefore safe to eliminate the call, return true,
if (GET_CODE (XEXP (p, 0)) == USE
&& MEM_P (XEXP (XEXP (p, 0), 0)))
{
- rtx mem = XEXP (XEXP (p, 0), 0), addr, size;
- HOST_WIDE_INT off = 0;
- size = MEM_SIZE (mem);
- if (size == NULL_RTX)
+ rtx mem = XEXP (XEXP (p, 0), 0), addr;
+ HOST_WIDE_INT off = 0, size;
+ if (!MEM_SIZE_KNOWN_P (mem))
return false;
+ size = MEM_SIZE (mem);
addr = XEXP (mem, 0);
if (GET_CODE (addr) == PLUS
&& REG_P (XEXP (addr, 0))
return false;
}
min_sp_off = MIN (min_sp_off, off);
- max_sp_off = MAX (max_sp_off, off + INTVAL (size));
+ max_sp_off = MAX (max_sp_off, off + size);
}
if (min_sp_off >= max_sp_off)
set = single_set (DF_REF_INSN (defs->ref));
off += INTVAL (XEXP (SET_SRC (set), 1));
}
- for (byte = off; byte < off + INTVAL (MEM_SIZE (mem)); byte++)
+ for (byte = off; byte < off + MEM_SIZE (mem); byte++)
{
if (!bitmap_set_bit (sp_bytes, byte - min_sp_off))
gcc_unreachable ();
for (insn = PREV_INSN (call_insn); insn; insn = prev_insn)
{
rtx set, mem, addr;
- HOST_WIDE_INT off, byte;
+ HOST_WIDE_INT off;
if (insn == BB_HEAD (BLOCK_FOR_INSN (call_insn)))
prev_insn = NULL_RTX;
if (CALL_P (insn))
break;
- if (!INSN_P (insn))
+ if (!NONDEBUG_INSN_P (insn))
continue;
set = single_set (insn);
break;
}
- if (GET_MODE_SIZE (GET_MODE (mem)) == 0)
+ if (GET_MODE_SIZE (GET_MODE (mem)) == 0
+ || !check_argument_store (mem, off, min_sp_off,
+ max_sp_off, sp_bytes))
break;
- for (byte = off; byte < off + GET_MODE_SIZE (GET_MODE (mem)); byte++)
- {
- if (byte < min_sp_off
- || byte >= max_sp_off
- || !bitmap_clear_bit (sp_bytes, byte - min_sp_off))
- break;
- }
-
if (!deletable_insn_p (insn, fast, NULL))
break;
}
-/* Delete all REG_EQUAL notes of the registers INSN writes, to prevent
- bad dangling REG_EQUAL notes. */
+/* Remove all REG_EQUAL and REG_EQUIV notes referring to the registers INSN
+ writes to. */
static void
-delete_corresponding_reg_eq_notes (rtx insn)
+remove_reg_equal_equiv_notes_for_defs (rtx insn)
{
df_ref *def_rec;
+
for (def_rec = DF_INSN_DEFS (insn); *def_rec; def_rec++)
- {
- df_ref def = *def_rec;
- unsigned int regno = DF_REF_REGNO (def);
- /* This loop is a little tricky. We cannot just go down the
- chain because it is being modified by the actions in the
- loop. So we just get the head. We plan to drain the list
- anyway. */
- while (DF_REG_EQ_USE_CHAIN (regno))
+ remove_reg_equal_equiv_notes_for_regno (DF_REF_REGNO (*def_rec));
+}
+
+/* Scan all BBs for debug insns and reset those that reference values
+ defined in unmarked insns. */
+
+static void
+reset_unmarked_insns_debug_uses (void)
+{
+ basic_block bb;
+ rtx insn, next;
+
+ FOR_EACH_BB_REVERSE (bb)
+ FOR_BB_INSNS_REVERSE_SAFE (bb, insn, next)
+ if (DEBUG_INSN_P (insn))
{
- df_ref eq_use = DF_REG_EQ_USE_CHAIN (regno);
- rtx noted_insn = DF_REF_INSN (eq_use);
- rtx note = find_reg_note (noted_insn, REG_EQUAL, NULL_RTX);
- if (!note)
- note = find_reg_note (noted_insn, REG_EQUIV, NULL_RTX);
-
- /* This assert is generally triggered when someone deletes a
- REG_EQUAL or REG_EQUIV note by hacking the list manually
- rather than calling remove_note. */
- gcc_assert (note);
- remove_note (noted_insn, note);
+ df_ref *use_rec;
+
+ for (use_rec = DF_INSN_USES (insn); *use_rec; use_rec++)
+ {
+ df_ref use = *use_rec;
+ struct df_link *defs;
+ for (defs = DF_REF_CHAIN (use); defs; defs = defs->next)
+ {
+ rtx ref_insn;
+ if (DF_REF_IS_ARTIFICIAL (defs->ref))
+ continue;
+ ref_insn = DF_REF_INSN (defs->ref);
+ if (!marked_insn_p (ref_insn))
+ break;
+ }
+ if (!defs)
+ continue;
+ /* ??? FIXME could we propagate the values assigned to
+ each of the DEFs? */
+ INSN_VAR_LOCATION_LOC (insn) = gen_rtx_UNKNOWN_VAR_LOC ();
+ df_insn_rescan_debug_internal (insn);
+ break;
+ }
}
- }
}
-
/* Delete every instruction that hasn't been marked. */
static void
FOR_EACH_BB_REVERSE (bb)
FOR_BB_INSNS_REVERSE_SAFE (bb, insn, next)
- if (INSN_P (insn))
+ if (NONDEBUG_INSN_P (insn))
{
/* Always delete no-op moves. */
if (noop_move_p (insn))
if (dump_file)
fprintf (dump_file, "DCE: Deleting insn %d\n", INSN_UID (insn));
- /* Before we delete the insn we have to delete REG_EQUAL notes
+ /* Before we delete the insn we have to remove the REG_EQUAL notes
for the destination regs in order to avoid dangling notes. */
- delete_corresponding_reg_eq_notes (insn);
+ remove_reg_equal_equiv_notes_for_defs (insn);
/* If a pure or const call is deleted, this may make the cfg
have unreachable blocks. We rememeber this and call
FOR_EACH_BB (bb)
{
FOR_BB_INSNS_REVERSE_SAFE (bb, insn, prev)
- if (INSN_P (insn))
+ if (NONDEBUG_INSN_P (insn))
{
/* Don't mark argument stores now. They will be marked
if needed when the associated CALL is marked. */
}
VEC_free (rtx, heap, worklist);
+ if (MAY_HAVE_DEBUG_INSNS)
+ reset_unmarked_insns_debug_uses ();
+
/* Before any insns are deleted, we must remove the chains since
they are not bidirectional. */
df_remove_problem (df_chain);
{
{
RTL_PASS,
- "ud dce", /* name */
+ "ud_dce", /* name */
gate_ud_dce, /* gate */
rest_of_handle_ud_dce, /* execute */
NULL, /* sub */
0, /* properties_provided */
0, /* properties_destroyed */
0, /* todo_flags_start */
- TODO_dump_func |
TODO_df_finish | TODO_verify_rtl_sharing |
TODO_ggc_collect /* todo_flags_finish */
}
{
{
RTL_PASS,
- "rtl dce", /* name */
+ "rtl_dce", /* name */
gate_fast_dce, /* gate */
rest_of_handle_fast_dce, /* execute */
NULL, /* sub */
0, /* properties_provided */
0, /* properties_destroyed */
0, /* todo_flags_start */
- TODO_dump_func |
TODO_df_finish | TODO_verify_rtl_sharing |
TODO_ggc_collect /* todo_flags_finish */
}
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