static void undo_commit (void);
static rtx *find_split_point (rtx *, rtx);
static rtx subst (rtx, rtx, rtx, int, int);
-static rtx combine_simplify_rtx (rtx, enum machine_mode, int, int);
+static rtx combine_simplify_rtx (rtx, enum machine_mode, int);
static rtx simplify_if_then_else (rtx);
static rtx simplify_set (rtx);
-static rtx simplify_logical (rtx, int);
+static rtx simplify_logical (rtx);
static rtx expand_compound_operation (rtx);
static rtx expand_field_assignment (rtx);
static rtx make_extraction (enum machine_mode, rtx, HOST_WIDE_INT,
static void record_promoted_value (rtx, rtx);
static rtx reversed_comparison (rtx, enum machine_mode, rtx, rtx);
static enum rtx_code combine_reversed_comparison_code (rtx);
+static int unmentioned_reg_p_1 (rtx *, void *);
+static bool unmentioned_reg_p (rtx, rtx);
\f
/* Substitute NEWVAL, an rtx expression, into INTO, a place in some
insn. The substitution can be undone by undo_all. If INTO is already
&new_direct_jump_p)) != 0)
goto retry;
+ /* Try this insn with each REG_EQUAL note it links back to. */
+ for (links = LOG_LINKS (insn); links; links = XEXP (links, 1))
+ {
+ rtx set, note;
+ rtx temp = XEXP (links, 0);
+ if ((set = single_set (temp)) != 0
+ && (note = find_reg_equal_equiv_note (temp)) != 0
+ && GET_CODE (XEXP (note, 0)) != EXPR_LIST
+ /* Avoid using a register that may already been marked
+ dead by an earlier instruction. */
+ && ! unmentioned_reg_p (XEXP (note, 0), SET_SRC (set)))
+ {
+ /* Temporarily replace the set's source with the
+ contents of the REG_EQUAL note. The insn will
+ be deleted or recognized by try_combine. */
+ rtx orig = SET_SRC (set);
+ SET_SRC (set) = XEXP (note, 0);
+ next = try_combine (insn, temp, NULL_RTX,
+ &new_direct_jump_p);
+ if (next)
+ goto retry;
+ SET_SRC (set) = orig;
+ }
+ }
+
if (GET_CODE (insn) != NOTE)
record_dead_and_set_regs (insn);
/* If X is sufficiently simple, don't bother trying to do anything
with it. */
if (code != CONST_INT && code != REG && code != CLOBBER)
- x = combine_simplify_rtx (x, op0_mode, i == 3, in_dest);
+ x = combine_simplify_rtx (x, op0_mode, in_dest);
if (GET_CODE (x) == code)
break;
outer level; call `subst' to simplify recursively. Return the new
expression.
- OP0_MODE is the original mode of XEXP (x, 0); LAST is nonzero if this
- will be the iteration even if an expression with a code different from
- X is returned; IN_DEST is nonzero if we are inside a SET_DEST. */
+ OP0_MODE is the original mode of XEXP (x, 0). IN_DEST is nonzero
+ if we are inside a SET_DEST. */
static rtx
-combine_simplify_rtx (rtx x, enum machine_mode op0_mode, int last,
- int in_dest)
+combine_simplify_rtx (rtx x, enum machine_mode op0_mode, int in_dest)
{
enum rtx_code code = GET_CODE (x);
enum machine_mode mode = GET_MODE (x);
{
/* Try to simplify the expression further. */
rtx tor = gen_binary (IOR, mode, XEXP (x, 0), XEXP (x, 1));
- temp = combine_simplify_rtx (tor, mode, last, in_dest);
+ temp = combine_simplify_rtx (tor, mode, in_dest);
/* If we could, great. If not, do not go ahead with the IOR
replacement, since PLUS appears in many special purpose
case AND:
case IOR:
case XOR:
- return simplify_logical (x, last);
+ return simplify_logical (x);
case ABS:
/* (abs (neg <foo>)) -> (abs <foo>) */
}
\f
/* Simplify, X, and AND, IOR, or XOR operation, and return the simplified
- result. LAST is nonzero if this is the last retry. */
+ result. */
static rtx
-simplify_logical (rtx x, int last)
+simplify_logical (rtx x)
{
enum machine_mode mode = GET_MODE (x);
rtx op0 = XEXP (x, 0);
/* If we have (ior (and (X C1) C2)) and the next restart would be
the last, simplify this by making C1 as small as possible
- and then exit. */
- if (last
- && GET_CODE (x) == IOR && GET_CODE (op0) == AND
+ and then exit. Only do this if C1 actually changes: for now
+ this only saves memory but, should this transformation be
+ moved to simplify-rtx.c, we'd risk unbounded recursion there. */
+ if (GET_CODE (x) == IOR && GET_CODE (op0) == AND
&& GET_CODE (XEXP (op0, 1)) == CONST_INT
- && GET_CODE (op1) == CONST_INT)
+ && GET_CODE (op1) == CONST_INT
+ && (INTVAL (XEXP (op0, 1)) & INTVAL (op1)) != 0)
return gen_binary (IOR, mode,
gen_binary (AND, mode, XEXP (op0, 0),
GEN_INT (INTVAL (XEXP (op0, 1))
}
}
\f
+/* Subroutine of unmentioned_reg_p and callback from for_each_rtx.
+ Check whether the expression pointer to by LOC is a register or
+ memory, and if so return 1 if it isn't mentioned in the rtx EXPR.
+ Otherwise return zero. */
+
+static int
+unmentioned_reg_p_1 (rtx *loc, void *expr)
+{
+ rtx x = *loc;
+
+ if (x != NULL_RTX
+ && (GET_CODE (x) == REG || GET_CODE (x) == MEM)
+ && ! reg_mentioned_p (x, (rtx) expr))
+ return 1;
+ return 0;
+}
+
+/* Check for any register or memory mentioned in EQUIV that is not
+ mentioned in EXPR. This is used to restrict EQUIV to "specializations"
+ of EXPR where some registers may have been replaced by constants. */
+
+static bool
+unmentioned_reg_p (rtx equiv, rtx expr)
+{
+ return for_each_rtx (&equiv, unmentioned_reg_p_1, expr);
+}
+\f
/* Compute INSN_CUID for INSN, which is an insn made by combine. */
static int
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