/* Optimize jump instructions, for GNU compiler.
Copyright (C) 1987, 1988, 1989, 1991, 1992, 1993, 1994, 1995, 1996, 1997
- 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2007, 2008, 2009
- Free Software Foundation, Inc.
+ 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2007, 2008, 2009, 2010,
+ 2011 Free Software Foundation, Inc.
This file is part of GCC.
JUMP_LABEL internal field. With this we can detect labels that
become unused because of the deletion of all the jumps that
formerly used them. The JUMP_LABEL info is sometimes looked
- at by later passes.
+ at by later passes. For return insns, it contains either a
+ RETURN or a SIMPLE_RETURN rtx.
The subroutines redirect_jump and invert_jump are used
from other passes as well. */
#include "insn-attr.h"
#include "recog.h"
#include "function.h"
+#include "basic-block.h"
#include "expr.h"
#include "except.h"
-#include "diagnostic.h"
-#include "toplev.h"
+#include "diagnostic-core.h"
#include "reload.h"
#include "predict.h"
#include "timevar.h"
static int invert_exp_1 (rtx, rtx);
static int returnjump_p_1 (rtx *, void *);
\f
-/* This function rebuilds the JUMP_LABEL field and REG_LABEL_TARGET
- notes in jumping insns and REG_LABEL_OPERAND notes in non-jumping
- instructions and jumping insns that have labels as operands
- (e.g. cbranchsi4). */
-void
-rebuild_jump_labels (rtx f)
+/* Worker for rebuild_jump_labels and rebuild_jump_labels_chain. */
+static void
+rebuild_jump_labels_1 (rtx f, bool count_forced)
{
rtx insn;
closely enough to delete them here, so make sure their reference
count doesn't drop to zero. */
- for (insn = forced_labels; insn; insn = XEXP (insn, 1))
- if (LABEL_P (XEXP (insn, 0)))
- LABEL_NUSES (XEXP (insn, 0))++;
+ if (count_forced)
+ for (insn = forced_labels; insn; insn = XEXP (insn, 1))
+ if (LABEL_P (XEXP (insn, 0)))
+ LABEL_NUSES (XEXP (insn, 0))++;
timevar_pop (TV_REBUILD_JUMP);
}
+
+/* This function rebuilds the JUMP_LABEL field and REG_LABEL_TARGET
+ notes in jumping insns and REG_LABEL_OPERAND notes in non-jumping
+ instructions and jumping insns that have labels as operands
+ (e.g. cbranchsi4). */
+void
+rebuild_jump_labels (rtx f)
+{
+ rebuild_jump_labels_1 (f, true);
+}
+
+/* This function is like rebuild_jump_labels, but doesn't run over
+ forced_labels. It can be used on insn chains that aren't the
+ main function chain. */
+void
+rebuild_jump_labels_chain (rtx chain)
+{
+ rebuild_jump_labels_1 (chain, false);
+}
\f
/* Some old code expects exactly one BARRIER as the NEXT_INSN of a
non-fallthru insn. This is not generally true, as multiple barriers
0, /* properties_provided */
0, /* properties_destroyed */
0, /* todo_flags_start */
- TODO_dump_func /* todo_flags_finish */
+ 0 /* todo_flags_finish */
}
};
}
}
+/* A subroutine of mark_all_labels. Trivially propagate a simple label
+ load into a jump_insn that uses it. */
+
+static void
+maybe_propagate_label_ref (rtx jump_insn, rtx prev_nonjump_insn)
+{
+ rtx label_note, pc, pc_src;
+
+ pc = pc_set (jump_insn);
+ pc_src = pc != NULL ? SET_SRC (pc) : NULL;
+ label_note = find_reg_note (prev_nonjump_insn, REG_LABEL_OPERAND, NULL);
+
+ /* If the previous non-jump insn sets something to a label,
+ something that this jump insn uses, make that label the primary
+ target of this insn if we don't yet have any. That previous
+ insn must be a single_set and not refer to more than one label.
+ The jump insn must not refer to other labels as jump targets
+ and must be a plain (set (pc) ...), maybe in a parallel, and
+ may refer to the item being set only directly or as one of the
+ arms in an IF_THEN_ELSE. */
+
+ if (label_note != NULL && pc_src != NULL)
+ {
+ rtx label_set = single_set (prev_nonjump_insn);
+ rtx label_dest = label_set != NULL ? SET_DEST (label_set) : NULL;
+
+ if (label_set != NULL
+ /* The source must be the direct LABEL_REF, not a
+ PLUS, UNSPEC, IF_THEN_ELSE etc. */
+ && GET_CODE (SET_SRC (label_set)) == LABEL_REF
+ && (rtx_equal_p (label_dest, pc_src)
+ || (GET_CODE (pc_src) == IF_THEN_ELSE
+ && (rtx_equal_p (label_dest, XEXP (pc_src, 1))
+ || rtx_equal_p (label_dest, XEXP (pc_src, 2))))))
+ {
+ /* The CODE_LABEL referred to in the note must be the
+ CODE_LABEL in the LABEL_REF of the "set". We can
+ conveniently use it for the marker function, which
+ requires a LABEL_REF wrapping. */
+ gcc_assert (XEXP (label_note, 0) == XEXP (SET_SRC (label_set), 0));
+
+ mark_jump_label_1 (label_set, jump_insn, false, true);
+
+ gcc_assert (JUMP_LABEL (jump_insn) == XEXP (label_note, 0));
+ }
+ }
+}
+
/* Mark the label each jump jumps to.
Combine consecutive labels, and count uses of labels. */
mark_all_labels (rtx f)
{
rtx insn;
- rtx prev_nonjump_insn = NULL;
-
- for (insn = f; insn; insn = NEXT_INSN (insn))
- if (INSN_P (insn))
- {
- mark_jump_label (PATTERN (insn), insn, 0);
-
- /* If the previous non-jump insn sets something to a label,
- something that this jump insn uses, make that label the primary
- target of this insn if we don't yet have any. That previous
- insn must be a single_set and not refer to more than one label.
- The jump insn must not refer to other labels as jump targets
- and must be a plain (set (pc) ...), maybe in a parallel, and
- may refer to the item being set only directly or as one of the
- arms in an IF_THEN_ELSE. */
- if (! INSN_DELETED_P (insn)
- && JUMP_P (insn)
- && JUMP_LABEL (insn) == NULL)
- {
- rtx label_note = NULL;
- rtx pc = pc_set (insn);
- rtx pc_src = pc != NULL ? SET_SRC (pc) : NULL;
-
- if (prev_nonjump_insn != NULL)
- label_note
- = find_reg_note (prev_nonjump_insn, REG_LABEL_OPERAND, NULL);
-
- if (label_note != NULL && pc_src != NULL)
- {
- rtx label_set = single_set (prev_nonjump_insn);
- rtx label_dest
- = label_set != NULL ? SET_DEST (label_set) : NULL;
-
- if (label_set != NULL
- /* The source must be the direct LABEL_REF, not a
- PLUS, UNSPEC, IF_THEN_ELSE etc. */
- && GET_CODE (SET_SRC (label_set)) == LABEL_REF
- && (rtx_equal_p (label_dest, pc_src)
- || (GET_CODE (pc_src) == IF_THEN_ELSE
- && (rtx_equal_p (label_dest, XEXP (pc_src, 1))
- || rtx_equal_p (label_dest,
- XEXP (pc_src, 2))))))
-
- {
- /* The CODE_LABEL referred to in the note must be the
- CODE_LABEL in the LABEL_REF of the "set". We can
- conveniently use it for the marker function, which
- requires a LABEL_REF wrapping. */
- gcc_assert (XEXP (label_note, 0)
- == XEXP (SET_SRC (label_set), 0));
-
- mark_jump_label_1 (label_set, insn, false, true);
- gcc_assert (JUMP_LABEL (insn)
- == XEXP (SET_SRC (label_set), 0));
- }
- }
- }
- else if (! INSN_DELETED_P (insn))
- prev_nonjump_insn = insn;
- }
- else if (LABEL_P (insn))
- prev_nonjump_insn = NULL;
- /* If we are in cfglayout mode, there may be non-insns between the
- basic blocks. If those non-insns represent tablejump data, they
- contain label references that we must record. */
if (current_ir_type () == IR_RTL_CFGLAYOUT)
{
basic_block bb;
- rtx insn;
FOR_EACH_BB (bb)
{
+ /* In cfglayout mode, we don't bother with trivial next-insn
+ propagation of LABEL_REFs into JUMP_LABEL. This will be
+ handled by other optimizers using better algorithms. */
+ FOR_BB_INSNS (bb, insn)
+ {
+ gcc_assert (! INSN_DELETED_P (insn));
+ if (NONDEBUG_INSN_P (insn))
+ mark_jump_label (PATTERN (insn), insn, 0);
+ }
+
+ /* In cfglayout mode, there may be non-insns between the
+ basic blocks. If those non-insns represent tablejump data,
+ they contain label references that we must record. */
for (insn = bb->il.rtl->header; insn; insn = NEXT_INSN (insn))
if (INSN_P (insn))
{
gcc_assert (JUMP_TABLE_DATA_P (insn));
mark_jump_label (PATTERN (insn), insn, 0);
}
-
for (insn = bb->il.rtl->footer; insn; insn = NEXT_INSN (insn))
if (INSN_P (insn))
{
}
}
}
+ else
+ {
+ rtx prev_nonjump_insn = NULL;
+ for (insn = f; insn; insn = NEXT_INSN (insn))
+ {
+ if (INSN_DELETED_P (insn))
+ ;
+ else if (LABEL_P (insn))
+ prev_nonjump_insn = NULL;
+ else if (NONDEBUG_INSN_P (insn))
+ {
+ mark_jump_label (PATTERN (insn), insn, 0);
+ if (JUMP_P (insn))
+ {
+ if (JUMP_LABEL (insn) == NULL && prev_nonjump_insn != NULL)
+ maybe_propagate_label_ref (insn, prev_nonjump_insn);
+ }
+ else
+ prev_nonjump_insn = insn;
+ }
+ }
+ }
}
\f
/* Given a comparison (CODE ARG0 ARG1), inside an insn, INSN, return a code
{
#ifdef REVERSE_CONDITION
return REVERSE_CONDITION (code, mode);
-#endif
+#else
return reverse_condition (code);
+#endif
}
/* Try a few special cases based on the comparison code. */
return (GET_CODE (x) == IF_THEN_ELSE
&& ((GET_CODE (XEXP (x, 2)) == PC
&& (GET_CODE (XEXP (x, 1)) == LABEL_REF
- || GET_CODE (XEXP (x, 1)) == RETURN))
+ || ANY_RETURN_P (XEXP (x, 1))))
|| (GET_CODE (XEXP (x, 1)) == PC
&& (GET_CODE (XEXP (x, 2)) == LABEL_REF
- || GET_CODE (XEXP (x, 2)) == RETURN))));
+ || ANY_RETURN_P (XEXP (x, 2))))));
}
/* Return nonzero if INSN is a (possibly) conditional jump inside a
return 0;
if (XEXP (SET_SRC (x), 2) == pc_rtx
&& (GET_CODE (XEXP (SET_SRC (x), 1)) == LABEL_REF
- || GET_CODE (XEXP (SET_SRC (x), 1)) == RETURN))
+ || ANY_RETURN_P (XEXP (SET_SRC (x), 1))))
return 1;
if (XEXP (SET_SRC (x), 1) == pc_rtx
&& (GET_CODE (XEXP (SET_SRC (x), 2)) == LABEL_REF
- || GET_CODE (XEXP (SET_SRC (x), 2)) == RETURN))
+ || ANY_RETURN_P (XEXP (SET_SRC (x), 2))))
return 1;
return 0;
}
a = GET_CODE (XEXP (SET_SRC (x), 1));
b = GET_CODE (XEXP (SET_SRC (x), 2));
- return ((b == PC && (a == LABEL_REF || a == RETURN))
- || (a == PC && (b == LABEL_REF || b == RETURN)));
+ return ((b == PC && (a == LABEL_REF || a == RETURN || a == SIMPLE_RETURN))
+ || (a == PC
+ && (b == LABEL_REF || b == RETURN || b == SIMPLE_RETURN)));
}
/* Return the label of a conditional jump. */
switch (GET_CODE (x))
{
case RETURN:
+ case SIMPLE_RETURN:
case EH_RETURN:
return true;
return 1;
}
+/* Return true iff INSN is a jump and its JUMP_LABEL is a label, not
+ NULL or a return. */
+bool
+jump_to_label_p (rtx insn)
+{
+ return (JUMP_P (insn)
+ && JUMP_LABEL (insn) != NULL && !ANY_RETURN_P (JUMP_LABEL (insn)));
+}
+
#ifdef HAVE_cc0
/* Return nonzero if X is an RTX that only sets the condition codes
notes. If INSN is an INSN or a CALL_INSN or non-target operands of
a JUMP_INSN, and there is at least one CODE_LABEL referenced in
INSN, add a REG_LABEL_OPERAND note containing that label to INSN.
+ For returnjumps, the JUMP_LABEL will also be set as appropriate.
Note that two labels separated by a loop-beginning note
must be kept distinct if we have not yet done loop-optimization,
case CALL:
return;
+ case RETURN:
+ case SIMPLE_RETURN:
+ if (is_target)
+ {
+ gcc_assert (JUMP_LABEL (insn) == NULL || JUMP_LABEL (insn) == x);
+ JUMP_LABEL (insn) = x;
+ }
+ return;
+
case MEM:
in_mem = true;
break;
/* If deleting a jump, decrement the count of the label,
and delete the label if it is now unused. */
- if (JUMP_P (insn) && JUMP_LABEL (insn))
+ if (jump_to_label_p (insn))
{
rtx lab = JUMP_LABEL (insn), lab_next;
is also an unconditional jump in that case. */
}
\f
+/* A helper function for redirect_exp_1; examines its input X and returns
+ either a LABEL_REF around a label, or a RETURN if X was NULL. */
+static rtx
+redirect_target (rtx x)
+{
+ if (x == NULL_RTX)
+ return ret_rtx;
+ if (!ANY_RETURN_P (x))
+ return gen_rtx_LABEL_REF (Pmode, x);
+ return x;
+}
+
/* Throughout LOC, redirect OLABEL to NLABEL. Treat null OLABEL or
NLABEL as a return. Accrue modifications into the change group. */
int i;
const char *fmt;
- if (code == LABEL_REF)
- {
- if (XEXP (x, 0) == olabel)
- {
- rtx n;
- if (nlabel)
- n = gen_rtx_LABEL_REF (Pmode, nlabel);
- else
- n = gen_rtx_RETURN (VOIDmode);
-
- validate_change (insn, loc, n, 1);
- return;
- }
- }
- else if (code == RETURN && olabel == 0)
+ if ((code == LABEL_REF && XEXP (x, 0) == olabel)
+ || x == olabel)
{
- if (nlabel)
- x = gen_rtx_LABEL_REF (Pmode, nlabel);
- else
- x = gen_rtx_RETURN (VOIDmode);
- if (loc == &PATTERN (insn))
- x = gen_rtx_SET (VOIDmode, pc_rtx, x);
+ x = redirect_target (nlabel);
+ if (GET_CODE (x) == LABEL_REF && loc == &PATTERN (insn))
+ x = gen_rtx_SET (VOIDmode, pc_rtx, x);
validate_change (insn, loc, x, 1);
return;
}
- if (code == SET && nlabel == 0 && SET_DEST (x) == pc_rtx
+ if (code == SET && SET_DEST (x) == pc_rtx
+ && ANY_RETURN_P (nlabel)
&& GET_CODE (SET_SRC (x)) == LABEL_REF
&& XEXP (SET_SRC (x), 0) == olabel)
{
- validate_change (insn, loc, gen_rtx_RETURN (VOIDmode), 1);
+ validate_change (insn, loc, nlabel, 1);
return;
}
int ochanges = num_validated_changes ();
rtx *loc, asmop;
+ gcc_assert (nlabel != NULL_RTX);
asmop = extract_asm_operands (PATTERN (jump));
if (asmop)
{
jump target label is unused as a result, it and the code following
it may be deleted.
- If NLABEL is zero, we are to turn the jump into a (possibly conditional)
- RETURN insn.
+ Normally, NLABEL will be a label, but it may also be a RETURN rtx;
+ in that case we are to turn the jump into a (possibly conditional)
+ return insn.
The return value will be 1 if the change was made, 0 if it wasn't
- (this can only occur for NLABEL == 0). */
+ (this can only occur when trying to produce return insns). */
int
redirect_jump (rtx jump, rtx nlabel, int delete_unused)
{
rtx olabel = JUMP_LABEL (jump);
+ gcc_assert (nlabel != NULL_RTX);
+
if (nlabel == olabel)
return 1;
about this. */
gcc_assert (delete_unused >= 0);
JUMP_LABEL (jump) = nlabel;
- if (nlabel)
+ if (!ANY_RETURN_P (nlabel))
++LABEL_NUSES (nlabel);
/* Update labels in any REG_EQUAL note. */
if ((note = find_reg_note (jump, REG_EQUAL, NULL_RTX)) != NULL_RTX)
{
- if (!nlabel || (invert && !invert_exp_1 (XEXP (note, 0), jump)))
+ if (ANY_RETURN_P (nlabel)
+ || (invert && !invert_exp_1 (XEXP (note, 0), jump)))
remove_note (jump, note);
else
{
}
}
- if (olabel && --LABEL_NUSES (olabel) == 0 && delete_unused > 0
+ if (!ANY_RETURN_P (olabel)
+ && --LABEL_NUSES (olabel) == 0 && delete_unused > 0
/* Undefined labels will remain outside the insn stream. */
&& INSN_UID (olabel))
delete_related_insns (olabel);
case 'i':
if (XINT (x, i) != XINT (y, i))
- return 0;
+ {
+ if (((code == ASM_OPERANDS && i == 6)
+ || (code == ASM_INPUT && i == 1))
+ && locator_eq (XINT (x, i), XINT (y, i)))
+ break;
+ return 0;
+ }
break;
case 't':
OSDN Git Service
