/* Expands front end tree to back end RTL for GNU C-Compiler
Copyright (C) 1987, 1988, 1989, 1992, 1993, 1994, 1995, 1996, 1997,
- 1998, 1999, 2000, 2001, 2002 Free Software Foundation, Inc.
+ 1998, 1999, 2000, 2001, 2002, 2003 Free Software Foundation, Inc.
This file is part of GCC.
#include "ggc.h"
#include "langhooks.h"
#include "predict.h"
+#include "optabs.h"
/* Assume that case vectors are not pc-relative. */
#ifndef CASE_VECTOR_PC_RELATIVE
static void check_seenlabel PARAMS ((void));
static void do_jump_if_equal PARAMS ((rtx, rtx, rtx, int));
static int estimate_case_costs PARAMS ((case_node_ptr));
+static bool same_case_target_p PARAMS ((rtx, rtx));
+static void strip_default_case_nodes PARAMS ((case_node_ptr *, rtx));
+static bool lshift_cheap_p PARAMS ((void));
+static int case_bit_test_cmp PARAMS ((const void *, const void *));
+static void emit_case_bit_tests PARAMS ((tree, tree, tree, tree,
+ case_node_ptr, rtx));
static void group_case_nodes PARAMS ((case_node_ptr));
static void balance_case_nodes PARAMS ((case_node_ptr *,
case_node_ptr));
}
\f
/* Generate RTL for an asm statement (explicit assembler code).
- BODY is a STRING_CST node containing the assembler code text,
- or an ADDR_EXPR containing a STRING_CST. */
+ STRING is a STRING_CST node containing the assembler code text,
+ or an ADDR_EXPR containing a STRING_CST. VOL nonzero means the
+ insn is volatile; don't optimize it. */
void
-expand_asm (body)
- tree body;
+expand_asm (string, vol)
+ tree string;
+ int vol;
{
- if (TREE_CODE (body) == ADDR_EXPR)
- body = TREE_OPERAND (body, 0);
+ rtx body;
- emit_insn (gen_rtx_ASM_INPUT (VOIDmode,
- TREE_STRING_POINTER (body)));
+ if (TREE_CODE (string) == ADDR_EXPR)
+ string = TREE_OPERAND (string, 0);
+
+ body = gen_rtx_ASM_INPUT (VOIDmode, TREE_STRING_POINTER (string));
+
+ MEM_VOLATILE_P (body) = vol;
+
+ emit_insn (body);
+
clear_last_expr ();
}
will be true if the operand is read-write, i.e., if it is used as
an input as well as an output. If *CONSTRAINT_P is not in
canonical form, it will be made canonical. (Note that `+' will be
- rpelaced with `=' as part of this process.)
+ replaced with `=' as part of this process.)
Returns TRUE if all went well; FALSE if an error occurred. */
}
/* Loop through the constraint string. */
- for (p = constraint + 1; *p; ++p)
+ for (p = constraint + 1; *p; p += CONSTRAINT_LEN (*p, p))
switch (*p)
{
case '+':
default:
if (!ISALPHA (*p))
break;
- if (REG_CLASS_FROM_LETTER (*p) != NO_REGS)
+ if (REG_CLASS_FROM_CONSTRAINT (*p, p) != NO_REGS)
*allows_reg = true;
-#ifdef EXTRA_CONSTRAINT
- else if (EXTRA_ADDRESS_CONSTRAINT (*p))
+#ifdef EXTRA_CONSTRAINT_STR
+ else if (EXTRA_ADDRESS_CONSTRAINT (*p, p))
*allows_reg = true;
- else if (EXTRA_MEMORY_CONSTRAINT (*p))
+ else if (EXTRA_MEMORY_CONSTRAINT (*p, p))
*allows_mem = true;
else
{
/* Make sure constraint has neither `=', `+', nor '&'. */
- for (j = 0; j < c_len; j++)
+ for (j = 0; j < c_len; j += CONSTRAINT_LEN (constraint[j], constraint+j))
switch (constraint[j])
{
case '+': case '=': case '&':
*constraint_p = constraint;
c_len = strlen (constraint);
j = 0;
+ /* ??? At the end of the loop, we will skip the first part of
+ the matched constraint. This assumes not only that the
+ other constraint is an output constraint, but also that
+ the '=' or '+' come first. */
break;
}
else
j = end - constraint;
+ /* Anticipate increment at end of loop. */
+ j--;
}
/* Fall through. */
error ("invalid punctuation `%c' in constraint", constraint[j]);
return false;
}
- if (REG_CLASS_FROM_LETTER (constraint[j]) != NO_REGS)
+ if (REG_CLASS_FROM_CONSTRAINT (constraint[j], constraint + j)
+ != NO_REGS)
*allows_reg = true;
-#ifdef EXTRA_CONSTRAINT
- else if (EXTRA_ADDRESS_CONSTRAINT (constraint[j]))
+#ifdef EXTRA_CONSTRAINT_STR
+ else if (EXTRA_ADDRESS_CONSTRAINT (constraint[j], constraint + j))
*allows_reg = true;
- else if (EXTRA_MEMORY_CONSTRAINT (constraint[j]))
+ else if (EXTRA_MEMORY_CONSTRAINT (constraint[j], constraint + j))
*allows_mem = true;
else
{
/* Mark clobbered registers. */
if (i >= 0)
- SET_HARD_REG_BIT (clobbered_regs, i);
+ {
+ /* Clobbering the PIC register is an error */
+ if (i == (int) PIC_OFFSET_TABLE_REGNUM)
+ {
+ error ("PIC register `%s' clobbered in `asm'", regname);
+ return;
+ }
+
+ SET_HARD_REG_BIT (clobbered_regs, i);
+ }
}
clear_last_expr ();
bool is_inout;
bool allows_reg;
bool allows_mem;
+ rtx op;
if (!parse_output_constraint (&constraints[i], i, ninputs,
noutputs, &allows_mem, &allows_reg,
|| ! allows_reg
|| is_inout)
{
- output_rtx[i] = expand_expr (val, NULL_RTX, VOIDmode, EXPAND_WRITE);
+ op = expand_expr (val, NULL_RTX, VOIDmode, EXPAND_WRITE);
+ if (GET_CODE (op) == MEM)
+ op = validize_mem (op);
- if (! allows_reg && GET_CODE (output_rtx[i]) != MEM)
+ if (! allows_reg && GET_CODE (op) != MEM)
error ("output number %d not directly addressable", i);
- if ((! allows_mem && GET_CODE (output_rtx[i]) == MEM)
- || GET_CODE (output_rtx[i]) == CONCAT)
+ if ((! allows_mem && GET_CODE (op) == MEM)
+ || GET_CODE (op) == CONCAT)
{
- real_output_rtx[i] = protect_from_queue (output_rtx[i], 1);
- output_rtx[i] = gen_reg_rtx (GET_MODE (output_rtx[i]));
+ real_output_rtx[i] = protect_from_queue (op, 1);
+ op = gen_reg_rtx (GET_MODE (op));
if (is_inout)
- emit_move_insn (output_rtx[i], real_output_rtx[i]);
+ emit_move_insn (op, real_output_rtx[i]);
}
}
else
{
- output_rtx[i] = assign_temp (type, 0, 0, 1);
- TREE_VALUE (tail) = make_tree (type, output_rtx[i]);
+ op = assign_temp (type, 0, 0, 1);
+ op = validize_mem (op);
+ TREE_VALUE (tail) = make_tree (type, op);
}
+ output_rtx[i] = op;
generating_concat_p = old_generating_concat_p;
/* Never pass a CONCAT to an ASM. */
if (GET_CODE (op) == CONCAT)
op = force_reg (GET_MODE (op), op);
+ else if (GET_CODE (op) == MEM)
+ op = validize_mem (op);
if (asm_operand_ok (op, constraint) <= 0)
{
warning ("asm operand %d probably doesn't match constraints",
i + noutputs);
else if (CONSTANT_P (op))
- op = force_const_mem (TYPE_MODE (type), op);
+ {
+ op = force_const_mem (TYPE_MODE (type), op);
+ op = validize_mem (op);
+ }
else if (GET_CODE (op) == REG
|| GET_CODE (op) == SUBREG
|| GET_CODE (op) == ADDRESSOF
(TYPE_QUALS (type)
| TYPE_QUAL_CONST));
rtx memloc = assign_temp (qual_type, 1, 1, 1);
-
+ memloc = validize_mem (memloc);
emit_move_insn (memloc, op);
op = memloc;
}
if (want_value == -1)
want_value = expr_stmts_for_value != 0;
- /* If -W, warn about statements with no side effects,
+ /* If -Wextra, warn about statements with no side effects,
except for an explicit cast to void (e.g. for assert()), and
except for last statement in ({...}) where they may be useful. */
if (! want_value
end_label:
We rely on the presence of NOTE_INSN_LOOP_END_TOP_COND to mark
- the end of the entry condtional. Without this, our lexical scan
+ the end of the entry conditional. Without this, our lexical scan
can't tell the difference between an entry conditional and a
body conditional that exits the loop. Mistaking the two means
that we can misplace the NOTE_INSN_LOOP_CONT note, which can
SET_DECL_RTL (decl, gen_reg_rtx (reg_mode));
- if (GET_CODE (DECL_RTL (decl)) == REG)
- REGNO_DECL (REGNO (DECL_RTL (decl))) = decl;
- else if (GET_CODE (DECL_RTL (decl)) == CONCAT)
- {
- REGNO_DECL (REGNO (XEXP (DECL_RTL (decl), 0))) = decl;
- REGNO_DECL (REGNO (XEXP (DECL_RTL (decl), 1))) = decl;
- }
-
mark_user_reg (DECL_RTL (decl));
if (POINTER_TYPE_P (type))
}
\f
+/* Maximum number of case bit tests. */
+#define MAX_CASE_BIT_TESTS 3
+
+/* By default, enable case bit tests on targets with ashlsi3. */
+#ifndef CASE_USE_BIT_TESTS
+#define CASE_USE_BIT_TESTS (ashl_optab->handlers[word_mode].insn_code \
+ != CODE_FOR_nothing)
+#endif
+
+
+/* A case_bit_test represents a set of case nodes that may be
+ selected from using a bit-wise comparison. HI and LO hold
+ the integer to be tested against, LABEL contains the label
+ to jump to upon success and BITS counts the number of case
+ nodes handled by this test, typically the number of bits
+ set in HI:LO. */
+
+struct case_bit_test
+{
+ HOST_WIDE_INT hi;
+ HOST_WIDE_INT lo;
+ rtx label;
+ int bits;
+};
+
+/* Determine whether "1 << x" is relatively cheap in word_mode. */
+
+static bool lshift_cheap_p ()
+{
+ static bool init = false;
+ static bool cheap = true;
+
+ if (!init)
+ {
+ rtx reg = gen_rtx_REG (word_mode, 10000);
+ int cost = rtx_cost (gen_rtx_ASHIFT (word_mode, const1_rtx, reg), SET);
+ cheap = cost < COSTS_N_INSNS (3);
+ init = true;
+ }
+
+ return cheap;
+}
+
+/* Comparison function for qsort to order bit tests by decreasing
+ number of case nodes, i.e. the node with the most cases gets
+ tested first. */
+
+static int case_bit_test_cmp (p1, p2)
+ const void *p1;
+ const void *p2;
+{
+ const struct case_bit_test *d1 = p1;
+ const struct case_bit_test *d2 = p2;
+
+ return d2->bits - d1->bits;
+}
+
+/* Expand a switch statement by a short sequence of bit-wise
+ comparisons. "switch(x)" is effectively converted into
+ "if ((1 << (x-MINVAL)) & CST)" where CST and MINVAL are
+ integer constants.
+
+ INDEX_EXPR is the value being switched on, which is of
+ type INDEX_TYPE. MINVAL is the lowest case value of in
+ the case nodes, of INDEX_TYPE type, and RANGE is highest
+ value minus MINVAL, also of type INDEX_TYPE. NODES is
+ the set of case nodes, and DEFAULT_LABEL is the label to
+ branch to should none of the cases match.
+
+ There *MUST* be MAX_CASE_BIT_TESTS or less unique case
+ node targets. */
+
+static void
+emit_case_bit_tests (index_type, index_expr, minval, range,
+ nodes, default_label)
+ tree index_type, index_expr, minval, range;
+ case_node_ptr nodes;
+ rtx default_label;
+{
+ struct case_bit_test test[MAX_CASE_BIT_TESTS];
+ enum machine_mode mode;
+ rtx expr, index, label;
+ unsigned int i,j,lo,hi;
+ struct case_node *n;
+ unsigned int count;
+
+ count = 0;
+ for (n = nodes; n; n = n->right)
+ {
+ label = label_rtx (n->code_label);
+ for (i = 0; i < count; i++)
+ if (same_case_target_p (label, test[i].label))
+ break;
+
+ if (i == count)
+ {
+ if (count >= MAX_CASE_BIT_TESTS)
+ abort ();
+ test[i].hi = 0;
+ test[i].lo = 0;
+ test[i].label = label;
+ test[i].bits = 1;
+ count++;
+ }
+ else
+ test[i].bits++;
+
+ lo = tree_low_cst (fold (build (MINUS_EXPR, index_type,
+ n->low, minval)), 1);
+ hi = tree_low_cst (fold (build (MINUS_EXPR, index_type,
+ n->high, minval)), 1);
+ for (j = lo; j <= hi; j++)
+ if (j >= HOST_BITS_PER_WIDE_INT)
+ test[i].hi |= (HOST_WIDE_INT) 1 << (j - HOST_BITS_PER_INT);
+ else
+ test[i].lo |= (HOST_WIDE_INT) 1 << j;
+ }
+
+ qsort (test, count, sizeof(*test), case_bit_test_cmp);
+
+ index_expr = fold (build (MINUS_EXPR, index_type,
+ convert (index_type, index_expr),
+ convert (index_type, minval)));
+ index = expand_expr (index_expr, NULL_RTX, VOIDmode, 0);
+ emit_queue ();
+ index = protect_from_queue (index, 0);
+ do_pending_stack_adjust ();
+
+ mode = TYPE_MODE (index_type);
+ expr = expand_expr (range, NULL_RTX, VOIDmode, 0);
+ emit_cmp_and_jump_insns (index, expr, GTU, NULL_RTX, mode, 1,
+ default_label);
+
+ index = convert_to_mode (word_mode, index, 0);
+ index = expand_binop (word_mode, ashl_optab, const1_rtx,
+ index, NULL_RTX, 1, OPTAB_WIDEN);
+
+ for (i = 0; i < count; i++)
+ {
+ expr = immed_double_const (test[i].lo, test[i].hi, word_mode);
+ expr = expand_binop (word_mode, and_optab, index, expr,
+ NULL_RTX, 1, OPTAB_WIDEN);
+ emit_cmp_and_jump_insns (expr, const0_rtx, NE, NULL_RTX,
+ word_mode, 1, test[i].label);
+ }
+
+ emit_jump (default_label);
+}
/* Terminate a case (Pascal) or switch (C) statement
in which ORIG_INDEX is the expression to be tested.
{
tree minval = NULL_TREE, maxval = NULL_TREE, range = NULL_TREE;
rtx default_label = 0;
- struct case_node *n;
- unsigned int count;
+ struct case_node *n, *m;
+ unsigned int count, uniq;
rtx index;
rtx table_label;
int ncases;
rtx *labelvec;
int i;
- rtx before_case, end;
+ rtx before_case, end, lab;
struct nesting *thiscase = case_stack;
tree index_expr, index_type;
+ bool exit_done = false;
int unsignedp;
/* Don't crash due to previous errors. */
if (thiscase == NULL)
return;
- table_label = gen_label_rtx ();
index_expr = thiscase->data.case_stmt.index_expr;
index_type = TREE_TYPE (index_expr);
unsignedp = TREE_UNSIGNED (index_type);
{
thiscase->data.case_stmt.default_label
= build_decl (LABEL_DECL, NULL_TREE, NULL_TREE);
+ /* Share the exit label if possible. */
+ if (thiscase->exit_label)
+ {
+ SET_DECL_RTL (thiscase->data.case_stmt.default_label,
+ thiscase->exit_label);
+ exit_done = true;
+ }
expand_label (thiscase->data.case_stmt.default_label);
}
default_label = label_rtx (thiscase->data.case_stmt.default_label);
/* Simplify the case-list before we count it. */
group_case_nodes (thiscase->data.case_stmt.case_list);
+ strip_default_case_nodes (&thiscase->data.case_stmt.case_list,
+ default_label);
/* Get upper and lower bounds of case values.
Also convert all the case values to the index expr's data type. */
+ uniq = 0;
count = 0;
for (n = thiscase->data.case_stmt.case_list; n; n = n->right)
{
/* A range counts double, since it requires two compares. */
if (! tree_int_cst_equal (n->low, n->high))
count++;
+
+ /* Count the number of unique case node targets. */
+ uniq++;
+ lab = label_rtx (n->code_label);
+ for (m = thiscase->data.case_stmt.case_list; m != n; m = m->right)
+ if (same_case_target_p (label_rtx (m->code_label), lab))
+ {
+ uniq--;
+ break;
+ }
}
/* Compute span of values. */
emit_jump (default_label);
}
+ /* Try implementing this switch statement by a short sequence of
+ bit-wise comparisons. However, we let the binary-tree case
+ below handle constant index expressions. */
+ else if (CASE_USE_BIT_TESTS
+ && ! TREE_CONSTANT (index_expr)
+ && compare_tree_int (range, GET_MODE_BITSIZE (word_mode)) < 0
+ && lshift_cheap_p ()
+ && ((uniq == 1 && count >= 3)
+ || (uniq == 2 && count >= 5)
+ || (uniq == 3 && count >= 6)))
+ {
+ /* Optimize the case where all the case values fit in a
+ word without having to subtract MINVAL. In this case,
+ we can optimize away the subtraction. */
+ if (compare_tree_int (minval, 0) > 0
+ && compare_tree_int (maxval, GET_MODE_BITSIZE (word_mode)) < 0)
+ {
+ minval = integer_zero_node;
+ range = maxval;
+ }
+ emit_case_bit_tests (index_type, index_expr, minval, range,
+ thiscase->data.case_stmt.case_list,
+ default_label);
+ }
+
/* If range of values is much bigger than number of values,
make a sequence of conditional branches instead of a dispatch.
If the switch-index is a constant, do it this way
#ifndef ASM_OUTPUT_ADDR_DIFF_ELT
|| flag_pic
#endif
- || TREE_CODE (index_expr) == INTEGER_CST
- || (TREE_CODE (index_expr) == COMPOUND_EXPR
- && TREE_CODE (TREE_OPERAND (index_expr, 1)) == INTEGER_CST))
+ || TREE_CONSTANT (index_expr))
{
index = expand_expr (index_expr, NULL_RTX, VOIDmode, 0);
}
else
{
+ table_label = gen_label_rtx ();
if (! try_casesi (index_type, index_expr, minval, range,
table_label, default_label))
{
else
end_cleanup_deferral ();
- if (thiscase->exit_label)
+ if (thiscase->exit_label && !exit_done)
emit_label (thiscase->exit_label);
POPSTACK (case_stack);
return 1;
}
+/* Determine whether two case labels branch to the same target. */
+
+static bool
+same_case_target_p (l1, l2)
+ rtx l1, l2;
+{
+ rtx i1, i2;
+
+ if (l1 == l2)
+ return true;
+
+ i1 = next_real_insn (l1);
+ i2 = next_real_insn (l2);
+ if (i1 == i2)
+ return true;
+
+ if (i1 && simplejump_p (i1))
+ {
+ l1 = XEXP (SET_SRC (PATTERN (i1)), 0);
+ }
+
+ if (i2 && simplejump_p (i2))
+ {
+ l2 = XEXP (SET_SRC (PATTERN (i2)), 0);
+ }
+ return l1 == l2;
+}
+
+/* Delete nodes that branch to the default label from a list of
+ case nodes. Eg. case 5: default: becomes just default: */
+
+static void
+strip_default_case_nodes (prev, deflab)
+ case_node_ptr *prev;
+ rtx deflab;
+{
+ case_node_ptr ptr;
+
+ while (*prev)
+ {
+ ptr = *prev;
+ if (same_case_target_p (label_rtx (ptr->code_label), deflab))
+ *prev = ptr->right;
+ else
+ prev = &ptr->right;
+ }
+}
+
/* Scan an ordered list of case nodes
combining those with consecutive values or ranges.
while (node)
{
- rtx lb = next_real_insn (label_rtx (node->code_label));
- rtx lb2;
+ rtx lab = label_rtx (node->code_label);
case_node_ptr np = node;
/* Try to group the successors of NODE with NODE. */
while (((np = np->right) != 0)
/* Do they jump to the same place? */
- && ((lb2 = next_real_insn (label_rtx (np->code_label))) == lb
- || (lb != 0 && lb2 != 0
- && simplejump_p (lb)
- && simplejump_p (lb2)
- && rtx_equal_p (SET_SRC (PATTERN (lb)),
- SET_SRC (PATTERN (lb2)))))
+ && same_case_target_p (label_rtx (np->code_label), lab)
/* Are their ranges consecutive? */
&& tree_int_cst_equal (np->low,
fold (build (PLUS_EXPR,
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