/* Alias analysis for GNU C
- Copyright (C) 1997, 1998, 1999, 2000, 2001 Free Software Foundation, Inc.
+ Copyright (C) 1997, 1998, 1999, 2000, 2001, 2002, 2003
+ Free Software Foundation, Inc.
Contributed by John Carr (jfc@mit.edu).
This file is part of GCC.
#include "config.h"
#include "system.h"
+#include "coretypes.h"
+#include "tm.h"
#include "rtl.h"
#include "tree.h"
#include "tm_p.h"
#include "splay-tree.h"
#include "ggc.h"
#include "langhooks.h"
+#include "timevar.h"
#include "target.h"
+#include "cgraph.h"
/* The alias sets assigned to MEMs assist the back-end in determining
which MEMs can alias which other MEMs. In general, two MEMs in
To see whether two alias sets can point to the same memory, we must
see if either alias set is a subset of the other. We need not trace
- past immediate descendents, however, since we propagate all
+ past immediate descendants, however, since we propagate all
grandchildren up one level.
Alias set zero is implicitly a superset of all other alias sets.
HOST_WIDE_INT alias_set;
/* The children of the alias set. These are not just the immediate
- children, but, in fact, all descendents. So, if we have:
+ children, but, in fact, all descendants. So, if we have:
struct T { struct S s; float f; }
static int memrefs_conflict_p PARAMS ((int, rtx, int, rtx,
HOST_WIDE_INT));
static void record_set PARAMS ((rtx, rtx, void *));
-static rtx find_base_term PARAMS ((rtx));
static int base_alias_check PARAMS ((rtx, rtx, enum machine_mode,
enum machine_mode));
static rtx find_base_value PARAMS ((rtx));
static int nonlocal_referenced_p PARAMS ((rtx));
static int nonlocal_set_p_1 PARAMS ((rtx *, void *));
static int nonlocal_set_p PARAMS ((rtx));
+static void memory_modified_1 PARAMS ((rtx, rtx, void *));
/* Set up all info needed to perform alias analysis on memory references. */
/* True when scanning insns from the start of the rtl to the
NOTE_INSN_FUNCTION_BEG note. */
-static int copying_arguments;
+static bool copying_arguments;
/* The splay-tree used to store the various alias set entries. */
static splay_tree alias_sets;
then they may not conflict. */
if ((t1 != 0 && readonly_fields_p (t1))
|| (t2 != 0 && readonly_fields_p (t2))
- || (t1 != 0 && TYPE_READONLY (t1))
- || (t2 != 0 && TYPE_READONLY (t2)))
+ || (t1 != 0 && lang_hooks.honor_readonly && TYPE_READONLY (t1))
+ || (t2 != 0 && lang_hooks.honor_readonly && TYPE_READONLY (t2)))
return 0;
/* If they are the same type, they must conflict. */
The test above is not sufficient because the scheduler may move
a copy out of an arg reg past the NOTE_INSN_FUNCTION_BEGIN. */
if ((regno >= FIRST_PSEUDO_REGISTER || fixed_regs[regno])
- && regno < reg_base_value_size
- && reg_base_value[regno])
- return reg_base_value[regno];
+ && regno < reg_base_value_size)
+ {
+ /* If we're inside init_alias_analysis, use new_reg_base_value
+ to reduce the number of relaxation iterations. */
+ if (new_reg_base_value && new_reg_base_value[regno]
+ && REG_N_SETS (regno) == 1)
+ return new_reg_base_value[regno];
+
+ if (reg_base_value[regno])
+ return reg_base_value[regno];
+ }
return src;
{
unsigned regno;
rtx src;
+ int n;
if (GET_CODE (dest) != REG)
return;
if (regno >= reg_base_value_size)
abort ();
+ /* If this spans multiple hard registers, then we must indicate that every
+ register has an unusable value. */
+ if (regno < FIRST_PSEUDO_REGISTER)
+ n = HARD_REGNO_NREGS (regno, GET_MODE (dest));
+ else
+ n = 1;
+ if (n != 1)
+ {
+ while (--n >= 0)
+ {
+ reg_seen[regno + n] = 1;
+ new_reg_base_value[regno + n] = 0;
+ }
+ return;
+ }
+
if (set)
{
/* A CLOBBER wipes out any old value but does not prevent a previously
}
/* Return 1 if X and Y are identical-looking rtx's.
+ Expect that X and Y has been already canonicalized.
We use the data in reg_known_value above to see if two registers with
different numbers are, in fact, equivalent. */
if (x == 0 || y == 0)
return 0;
- x = canon_rtx (x);
- y = canon_rtx (y);
-
if (x == y)
return 1;
case ADDRESSOF:
return (XINT (x, 1) == XINT (y, 1)
- && rtx_equal_for_memref_p (XEXP (x, 0), XEXP (y, 0)));
+ && rtx_equal_for_memref_p (XEXP (x, 0),
+ XEXP (y, 0)));
default:
break;
}
- /* For commutative operations, the RTX match if the operand match in any
- order. Also handle the simple binary and unary cases without a loop. */
- if (code == EQ || code == NE || GET_RTX_CLASS (code) == 'c')
+ /* canon_rtx knows how to handle plus. No need to canonicalize. */
+ if (code == PLUS)
return ((rtx_equal_for_memref_p (XEXP (x, 0), XEXP (y, 0))
&& rtx_equal_for_memref_p (XEXP (x, 1), XEXP (y, 1)))
|| (rtx_equal_for_memref_p (XEXP (x, 0), XEXP (y, 1))
&& rtx_equal_for_memref_p (XEXP (x, 1), XEXP (y, 0))));
+ /* For commutative operations, the RTX match if the operand match in any
+ order. Also handle the simple binary and unary cases without a loop. */
+ if (code == EQ || code == NE || GET_RTX_CLASS (code) == 'c')
+ {
+ rtx xop0 = canon_rtx (XEXP (x, 0));
+ rtx yop0 = canon_rtx (XEXP (y, 0));
+ rtx yop1 = canon_rtx (XEXP (y, 1));
+
+ return ((rtx_equal_for_memref_p (xop0, yop0)
+ && rtx_equal_for_memref_p (canon_rtx (XEXP (x, 1)), yop1))
+ || (rtx_equal_for_memref_p (xop0, yop1)
+ && rtx_equal_for_memref_p (canon_rtx (XEXP (x, 1)), yop0)));
+ }
else if (GET_RTX_CLASS (code) == '<' || GET_RTX_CLASS (code) == '2')
- return (rtx_equal_for_memref_p (XEXP (x, 0), XEXP (y, 0))
- && rtx_equal_for_memref_p (XEXP (x, 1), XEXP (y, 1)));
+ {
+ return (rtx_equal_for_memref_p (canon_rtx (XEXP (x, 0)),
+ canon_rtx (XEXP (y, 0)))
+ && rtx_equal_for_memref_p (canon_rtx (XEXP (x, 1)),
+ canon_rtx (XEXP (y, 1))));
+ }
else if (GET_RTX_CLASS (code) == '1')
- return rtx_equal_for_memref_p (XEXP (x, 0), XEXP (y, 0));
+ return rtx_equal_for_memref_p (canon_rtx (XEXP (x, 0)),
+ canon_rtx (XEXP (y, 0)));
/* Compare the elements. If any pair of corresponding elements
fail to match, return 0 for the whole things.
/* And the corresponding elements must match. */
for (j = 0; j < XVECLEN (x, i); j++)
- if (rtx_equal_for_memref_p (XVECEXP (x, i, j),
- XVECEXP (y, i, j)) == 0)
+ if (rtx_equal_for_memref_p (canon_rtx (XVECEXP (x, i, j)),
+ canon_rtx (XVECEXP (y, i, j))) == 0)
return 0;
break;
case 'e':
- if (rtx_equal_for_memref_p (XEXP (x, i), XEXP (y, i)) == 0)
+ if (rtx_equal_for_memref_p (canon_rtx (XEXP (x, i)),
+ canon_rtx (XEXP (y, i))) == 0)
return 0;
break;
return 0;
}
-static rtx
+rtx
find_base_term (x)
rtx x;
{
}
if (offset)
- addr = gen_rtx_PLUS (GET_MODE (addr), XEXP (addr, 0), GEN_INT (offset));
+ addr = gen_rtx_PLUS (GET_MODE (addr), XEXP (addr, 0),
+ GEN_INT (offset));
else
addr = XEXP (addr, 0);
+ addr = canon_rtx (addr);
return addr;
}
C is nonzero, we are testing aliases between X and Y + C.
XSIZE is the size in bytes of the X reference,
similarly YSIZE is the size in bytes for Y.
+ Expect that canon_rtx has been already called for X and Y.
If XSIZE or YSIZE is zero, we do not know the amount of memory being
referenced (the reference was BLKmode), so make the most pessimistic
else if (GET_CODE (x) == LO_SUM)
x = XEXP (x, 1);
else
- x = canon_rtx (addr_side_effect_eval (x, xsize, 0));
+ x = addr_side_effect_eval (x, xsize, 0);
if (GET_CODE (y) == HIGH)
y = XEXP (y, 0);
else if (GET_CODE (y) == LO_SUM)
y = XEXP (y, 1);
else
- y = canon_rtx (addr_side_effect_eval (y, ysize, 0));
+ y = addr_side_effect_eval (y, ysize, 0);
if (rtx_equal_for_memref_p (x, y))
{
{
if (GET_CODE (y) == AND || ysize < -INTVAL (XEXP (x, 1)))
xsize = -1;
- return memrefs_conflict_p (xsize, XEXP (x, 0), ysize, y, c);
+ return memrefs_conflict_p (xsize, canon_rtx (XEXP (x, 0)), ysize, y, c);
}
if (GET_CODE (y) == AND && GET_CODE (XEXP (y, 1)) == CONST_INT)
{
a following reference, so we do nothing with that for now. */
if (GET_CODE (x) == AND || xsize < -INTVAL (XEXP (y, 1)))
ysize = -1;
- return memrefs_conflict_p (xsize, x, ysize, XEXP (y, 0), c);
+ return memrefs_conflict_p (xsize, x, ysize, canon_rtx (XEXP (y, 0)), c);
}
if (GET_CODE (x) == ADDRESSOF)
return GEN_INT (ioffset);
}
-/* Return nonzero if we can deterimine the exprs corresponding to memrefs
+/* Return nonzero if we can determine the exprs corresponding to memrefs
X and Y and they do not overlap. */
static int
varies);
}
-/* Returns non-zero if a write to X might alias a previous read from
- (or, if WRITEP is non-zero, a write to) MEM. */
+/* Returns nonzero if a write to X might alias a previous read from
+ (or, if WRITEP is nonzero, a write to) MEM. */
static int
write_dependence_p (mem, x, writep)
return 0;
}
-/* Returns non-zero if X might mention something which is not
+/* Returns nonzero if X might mention something which is not
local to the function and is not constant. */
static int
nonlocal_mentioned_p (x)
rtx x;
{
-
if (INSN_P (x))
{
if (GET_CODE (x) == CALL_INSN)
return 0;
}
-/* Returns non-zero if X might reference something which is not
+/* Returns nonzero if X might reference something which is not
local to the function and is not constant. */
static int
nonlocal_referenced_p (x)
rtx x;
{
-
if (INSN_P (x))
{
if (GET_CODE (x) == CALL_INSN)
return 0;
}
-/* Returns non-zero if X might set something which is not
+/* Returns nonzero if X might set something which is not
local to the function and is not constant. */
static int
nonlocal_set_p (x)
rtx x;
{
-
if (INSN_P (x))
{
if (GET_CODE (x) == CALL_INSN)
return for_each_rtx (&x, nonlocal_set_p_1, NULL);
}
-/* Mark the function if it is constant. */
+/* Mark the function if it is pure or constant. */
void
mark_constant_function ()
if (TREE_READONLY (current_function_decl)
|| DECL_IS_PURE (current_function_decl)
|| TREE_THIS_VOLATILE (current_function_decl)
- || TYPE_MODE (TREE_TYPE (current_function_decl)) == VOIDmode
|| current_function_has_nonlocal_goto
|| !(*targetm.binds_local_p) (current_function_decl))
return;
if (insn)
;
else if (nonlocal_memory_referenced)
- DECL_IS_PURE (current_function_decl) = 1;
+ {
+ cgraph_rtl_info (current_function_decl)->pure_function = 1;
+ DECL_IS_PURE (current_function_decl) = 1;
+ }
else
- TREE_READONLY (current_function_decl) = 1;
+ {
+ cgraph_rtl_info (current_function_decl)->const_function = 1;
+ TREE_READONLY (current_function_decl) = 1;
+ }
}
\f
alias_sets = splay_tree_new (splay_tree_compare_ints, 0, 0);
}
+/* Set MEMORY_MODIFIED when X modifies DATA (that is assumed
+ to be memory reference. */
+static bool memory_modified;
+static void
+memory_modified_1 (x, pat, data)
+ rtx x, pat ATTRIBUTE_UNUSED;
+ void *data;
+{
+ if (GET_CODE (x) == MEM)
+ {
+ if (anti_dependence (x, (rtx)data) || output_dependence (x, (rtx)data))
+ memory_modified = true;
+ }
+}
+
+
+/* Return true when INSN possibly modify memory contents of MEM
+ (ie address can be modified). */
+bool
+memory_modified_in_insn_p (mem, insn)
+ rtx mem, insn;
+{
+ if (!INSN_P (insn))
+ return false;
+ memory_modified = false;
+ note_stores (PATTERN (insn), memory_modified_1, mem);
+ return memory_modified;
+}
+
/* Initialize the aliasing machinery. Initialize the REG_KNOWN_VALUE
array. */
unsigned int ui;
rtx insn;
+ timevar_push (TV_ALIAS_ANALYSIS);
+
reg_known_value_size = maxreg;
reg_known_value
new_reg_base_value = (rtx *) xmalloc (reg_base_value_size * sizeof (rtx));
reg_seen = (char *) xmalloc (reg_base_value_size);
- if (! reload_completed && flag_unroll_loops)
+ if (! reload_completed && flag_old_unroll_loops)
{
/* ??? Why are we realloc'ing if we're just going to zero it? */
alias_invariant = (rtx *)xrealloc (alias_invariant,
/* We're at the start of the function each iteration through the
loop, so we're copying arguments. */
- copying_arguments = 1;
+ copying_arguments = true;
/* Wipe the potential alias information clean for this pass. */
memset ((char *) new_reg_base_value, 0, reg_base_value_size * sizeof (rtx));
}
else if (GET_CODE (insn) == NOTE
&& NOTE_LINE_NUMBER (insn) == NOTE_INSN_FUNCTION_BEG)
- copying_arguments = 0;
+ copying_arguments = false;
}
/* Now propagate values from new_reg_base_value to reg_base_value. */
new_reg_base_value = 0;
free (reg_seen);
reg_seen = 0;
+ timevar_pop (TV_ALIAS_ANALYSIS);
}
void
OSDN Git Service
