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-rw-r--r--gcc/alias.c222
1 files changed, 197 insertions, 25 deletions
diff --git a/gcc/alias.c b/gcc/alias.c
index a0f77d559a1..dbda2aec741 100644
--- a/gcc/alias.c
+++ b/gcc/alias.c
@@ -97,7 +97,8 @@ typedef struct alias_set_entry *alias_set_entry;
static int rtx_equal_for_memref_p (rtx, rtx);
static rtx find_symbolic_term (rtx);
-static int memrefs_conflict_p (int, rtx, int, rtx, HOST_WIDE_INT);
+/* APPLE LOCAL nop on true-dependence. */
+static int memrefs_conflict_p (int, rtx, int, rtx, HOST_WIDE_INT, int);
static void record_set (rtx, rtx, void *);
static int base_alias_check (rtx, rtx, enum machine_mode,
enum machine_mode);
@@ -113,6 +114,8 @@ static bool nonoverlapping_component_refs_p (tree, tree);
static tree decl_for_component_ref (tree);
static rtx adjust_offset_for_component_ref (tree, rtx);
static int nonoverlapping_memrefs_p (rtx, rtx);
+/* APPLE LOCAL aliasing improvement */
+static int overlapping_memrefs_p (rtx, rtx);
static int write_dependence_p (rtx, rtx, int);
static int nonlocal_mentioned_p_1 (rtx *, void *);
@@ -1612,6 +1615,8 @@ addr_side_effect_eval (rtx addr, int size, int n_refs)
return addr;
}
+/* APPLE LOCAL begin nop on true-dependence. */
+
/* Return nonzero if X and Y (memory addresses) could reference the
same location in memory. C is an offset accumulator. When
C is nonzero, we are testing aliases between X and Y + C.
@@ -1627,11 +1632,19 @@ addr_side_effect_eval (rtx addr, int size, int n_refs)
being referenced as a side effect. This can happen when using AND to
align memory references, as is done on the Alpha.
+ Caller can decide what value to return by passing memrefs_may_conflist as
+ 0 or 1. If 1, caller wants memrefs_conflict_p to assume conflict if
+ aliasing info is insufficient to decide on memory conflict. If 0,
+ caller wants memrefs_conflict_p to assume no conflict for insufficient
+ aliasing info.
+
Nice to notice that varying addresses cannot conflict with fp if no
local variables had their addresses taken, but that's too hard now. */
+
static int
-memrefs_conflict_p (int xsize, rtx x, int ysize, rtx y, HOST_WIDE_INT c)
+memrefs_conflict_p (int xsize, rtx x, int ysize, rtx y, HOST_WIDE_INT c,
+ int memrefs_may_conflist)
{
if (GET_CODE (x) == VALUE)
x = get_addr (x);
@@ -1679,25 +1692,31 @@ memrefs_conflict_p (int xsize, rtx x, int ysize, rtx y, HOST_WIDE_INT c)
rtx y1 = XEXP (y, 1);
if (rtx_equal_for_memref_p (x1, y1))
- return memrefs_conflict_p (xsize, x0, ysize, y0, c);
+ return memrefs_conflict_p (xsize, x0, ysize, y0, c,
+ memrefs_may_conflist);
if (rtx_equal_for_memref_p (x0, y0))
- return memrefs_conflict_p (xsize, x1, ysize, y1, c);
+ return memrefs_conflict_p (xsize, x1, ysize, y1, c,
+ memrefs_may_conflist);
if (GET_CODE (x1) == CONST_INT)
{
if (GET_CODE (y1) == CONST_INT)
return memrefs_conflict_p (xsize, x0, ysize, y0,
- c - INTVAL (x1) + INTVAL (y1));
+ c - INTVAL (x1) + INTVAL (y1),
+ memrefs_may_conflist);
else
return memrefs_conflict_p (xsize, x0, ysize, y,
- c - INTVAL (x1));
+ c - INTVAL (x1),
+ memrefs_may_conflist);
}
else if (GET_CODE (y1) == CONST_INT)
- return memrefs_conflict_p (xsize, x, ysize, y0, c + INTVAL (y1));
+ return memrefs_conflict_p (xsize, x, ysize, y0, c + INTVAL (y1),
+ memrefs_may_conflist);
- return 1;
+ return memrefs_may_conflist;
}
else if (GET_CODE (x1) == CONST_INT)
- return memrefs_conflict_p (xsize, x0, ysize, y, c - INTVAL (x1));
+ return memrefs_conflict_p (xsize, x0, ysize, y, c - INTVAL (x1),
+ memrefs_may_conflist);
}
else if (GET_CODE (y) == PLUS)
{
@@ -1707,9 +1726,10 @@ memrefs_conflict_p (int xsize, rtx x, int ysize, rtx y, HOST_WIDE_INT c)
rtx y1 = XEXP (y, 1);
if (GET_CODE (y1) == CONST_INT)
- return memrefs_conflict_p (xsize, x, ysize, y0, c + INTVAL (y1));
+ return memrefs_conflict_p (xsize, x, ysize, y0, c + INTVAL (y1),
+ memrefs_may_conflist);
else
- return 1;
+ return memrefs_may_conflist;
}
if (GET_CODE (x) == GET_CODE (y))
@@ -1724,7 +1744,7 @@ memrefs_conflict_p (int xsize, rtx x, int ysize, rtx y, HOST_WIDE_INT c)
rtx x1 = canon_rtx (XEXP (x, 1));
rtx y1 = canon_rtx (XEXP (y, 1));
if (! rtx_equal_for_memref_p (x1, y1))
- return 1;
+ return memrefs_may_conflist;
x0 = canon_rtx (XEXP (x, 0));
y0 = canon_rtx (XEXP (y, 0));
if (rtx_equal_for_memref_p (x0, y0))
@@ -1733,11 +1753,12 @@ memrefs_conflict_p (int xsize, rtx x, int ysize, rtx y, HOST_WIDE_INT c)
/* Can't properly adjust our sizes. */
if (GET_CODE (x1) != CONST_INT)
- return 1;
+ return memrefs_may_conflist;
xsize /= INTVAL (x1);
ysize /= INTVAL (x1);
c /= INTVAL (x1);
- return memrefs_conflict_p (xsize, x0, ysize, y0, c);
+ return memrefs_conflict_p (xsize, x0, ysize, y0, c,
+ memrefs_may_conflist);
}
case REG:
@@ -1754,7 +1775,8 @@ memrefs_conflict_p (int xsize, rtx x, int ysize, rtx y, HOST_WIDE_INT c)
break;
if (! memrefs_conflict_p (xsize, i_x ? i_x : x,
- ysize, i_y ? i_y : y, c))
+ ysize, i_y ? i_y : y, c,
+ memrefs_may_conflist))
return 0;
}
break;
@@ -1771,7 +1793,8 @@ memrefs_conflict_p (int xsize, rtx x, int ysize, rtx y, HOST_WIDE_INT c)
{
if (GET_CODE (y) == AND || ysize < -INTVAL (XEXP (x, 1)))
xsize = -1;
- return memrefs_conflict_p (xsize, canon_rtx (XEXP (x, 0)), ysize, y, c);
+ return memrefs_conflict_p (xsize, canon_rtx (XEXP (x, 0)), ysize, y, c,
+ memrefs_may_conflist);
}
if (GET_CODE (y) == AND && GET_CODE (XEXP (y, 1)) == CONST_INT)
{
@@ -1781,7 +1804,8 @@ memrefs_conflict_p (int xsize, rtx x, int ysize, rtx y, HOST_WIDE_INT c)
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, canon_rtx (XEXP (y, 0)), c);
+ return memrefs_conflict_p (xsize, x, ysize, canon_rtx (XEXP (y, 0)), c,
+ memrefs_may_conflist);
}
if (CONSTANT_P (x))
@@ -1797,24 +1821,28 @@ memrefs_conflict_p (int xsize, rtx x, int ysize, rtx y, HOST_WIDE_INT c)
{
if (GET_CODE (y) == CONST)
return memrefs_conflict_p (xsize, canon_rtx (XEXP (x, 0)),
- ysize, canon_rtx (XEXP (y, 0)), c);
+ ysize, canon_rtx (XEXP (y, 0)), c,
+ memrefs_may_conflist);
else
return memrefs_conflict_p (xsize, canon_rtx (XEXP (x, 0)),
- ysize, y, c);
+ ysize, y, c,
+ memrefs_may_conflist);
}
if (GET_CODE (y) == CONST)
return memrefs_conflict_p (xsize, x, ysize,
- canon_rtx (XEXP (y, 0)), c);
+ canon_rtx (XEXP (y, 0)), c,
+ memrefs_may_conflist);
if (CONSTANT_P (y))
return (xsize <= 0 || ysize <= 0
|| (rtx_equal_for_memref_p (x, y)
&& ((c >= 0 && xsize > c) || (c < 0 && ysize+c > 0))));
- return 1;
+ return memrefs_may_conflist;
}
- return 1;
+ return memrefs_may_conflist;
}
+/* APPLE LOCAL end nop on true-dependence. */
/* Functions to compute memory dependencies.
@@ -2117,6 +2145,119 @@ nonoverlapping_memrefs_p (rtx x, rtx y)
return sizex >= 0 && offsety >= offsetx + sizex;
}
+/* APPLE LOCAL begin aliasing improvement */
+/* Helper for the following. Return 1 only if we're sure of overlap. */
+
+static int
+overlapping_trees_p (tree exprx, tree expry)
+{
+ /* If no info about either one, can't tell. */
+ if (exprx == 0 || expry == 0)
+ return 0;
+
+ /* Top level code must match. */
+ if (TREE_CODE (exprx) != TREE_CODE (expry))
+ return 0;
+
+ /* Components. */
+ if (TREE_CODE (exprx) == COMPONENT_REF)
+ {
+ /* They must refer to the same field... */
+ if (TREE_OPERAND (exprx, 1) != TREE_OPERAND (expry, 1))
+ return 0;
+ /* ...of the same object. (The object may be null, which
+ will compare as not overlapping.) */
+ return overlapping_trees_p (TREE_OPERAND (exprx, 0),
+ TREE_OPERAND (expry, 0));
+ }
+
+ /* Pointers. */
+ if (TREE_CODE (exprx) == INDIRECT_REF)
+ return overlapping_trees_p (TREE_OPERAND (exprx, 0),
+ TREE_OPERAND (expry, 0));
+
+ if (TREE_CODE (exprx) == VAR_DECL
+ || TREE_CODE (exprx) == PARM_DECL
+ || TREE_CODE (exprx) == CONST_DECL
+ || TREE_CODE (exprx) == FUNCTION_DECL)
+ return exprx == expry;
+
+ return 0;
+}
+
+/* Return 1 if memrefs definitely overlap, 0 otherwise. */
+
+
+static int
+overlapping_memrefs_p (rtx x, rtx y)
+{
+ tree exprx = MEM_EXPR (x), expry = MEM_EXPR (y);
+ rtx offsetx = MEM_OFFSET (x), offsety = MEM_OFFSET (y);
+
+ /* See if offsets collide. Known but different offsets do not
+ overlap. Unknown offsets will if the underlying object is the same. */
+ if (offsetx != 0 && offsety != 0 && !rtx_equal_p (offsetx, offsety))
+ return 0;
+
+ return overlapping_trees_p (exprx, expry);
+}
+/* APPLE LOCAL end aliasing improvement */
+
+
+/* APPLE LOCAL begin nop on true-dependence. */
+/*
+ True dependence: X is read after store in MEM takes place.
+ This is similar to true_dependence. Except that function returns 1
+ only if it can determine the conflict. If it cannot or if there
+ is no conflict, it returns 0.
+*/
+
+int
+must_true_dependence (rtx mem, rtx x)
+{
+ rtx x_addr, mem_addr;
+ enum machine_mode mem_mode;
+
+ if (MEM_VOLATILE_P (x) && MEM_VOLATILE_P (mem))
+ return 1;
+
+ /* (mem:BLK (scratch)) is a special mechanism to conflict with everything.
+ This is used in epilogue deallocation functions. */
+ if (GET_MODE (x) == BLKmode && GET_CODE (XEXP (x, 0)) == SCRATCH)
+ return 1;
+ if (GET_MODE (mem) == BLKmode && GET_CODE (XEXP (mem, 0)) == SCRATCH)
+ return 1;
+
+ mem_mode = GET_MODE (mem);
+ x_addr = get_addr (XEXP (x, 0));
+ mem_addr = get_addr (XEXP (mem, 0));
+
+ /* APPLE LOCAL begin aliasing improvement */
+ if (overlapping_memrefs_p (mem, x))
+ return 1;
+ /* APPLE LOCAL end */
+
+ if (aliases_everything_p (x))
+ return 1;
+
+ x_addr = canon_rtx (x_addr);
+ mem_addr = canon_rtx (mem_addr);
+
+ /* We cannot use aliases_everything_p to test MEM, since we must look
+ at MEM_MODE, rather than GET_MODE (MEM). */
+ if (mem_mode == QImode || GET_CODE (mem_addr) == AND)
+ return 1;
+
+ /* In true_dependence we also allow BLKmode to alias anything. Why
+ don't we do this in anti_dependence and output_dependence? */
+ if (mem_mode == BLKmode || GET_MODE (x) == BLKmode)
+ return 1;
+
+ return memrefs_conflict_p (GET_MODE_SIZE (mem_mode), mem_addr,
+ SIZE_FOR_MODE (x), x_addr, 0, 0);
+}
+/* APPLE LOCAL end nop on true-dependence. */
+
/* True dependence: X is read after store in MEM takes place. */
int
@@ -2160,6 +2301,11 @@ true_dependence (rtx mem, enum machine_mode mem_mode, rtx x,
&& CONSTANT_POOL_ADDRESS_P (base))))
return 0;
+ /* APPLE LOCAL begin aliasing improvement */
+ if (overlapping_memrefs_p (mem, x))
+ return 1;
+ /* APPLE LOCAL end */
+
if (! base_alias_check (x_addr, mem_addr, GET_MODE (x), mem_mode))
return 0;
@@ -2167,7 +2313,8 @@ true_dependence (rtx mem, enum machine_mode mem_mode, rtx x,
mem_addr = canon_rtx (mem_addr);
if (! memrefs_conflict_p (GET_MODE_SIZE (mem_mode), mem_addr,
- SIZE_FOR_MODE (x), x_addr, 0))
+ /* APPLE LOCAL nop on true-dependence. */
+ SIZE_FOR_MODE (x), x_addr, 0, 1))
return 0;
if (aliases_everything_p (x))
@@ -2223,12 +2370,18 @@ canon_true_dependence (rtx mem, enum machine_mode mem_mode, rtx mem_addr,
x_addr = get_addr (XEXP (x, 0));
+ /* APPLE LOCAL begin aliasing improvement */
+ if (overlapping_memrefs_p (mem, x))
+ return 1;
+ /* APPLE LOCAL end */
+
if (! base_alias_check (x_addr, mem_addr, GET_MODE (x), mem_mode))
return 0;
x_addr = canon_rtx (x_addr);
if (! memrefs_conflict_p (GET_MODE_SIZE (mem_mode), mem_addr,
- SIZE_FOR_MODE (x), x_addr, 0))
+ /* APPLE LOCAL nop on true-dependence. */
+ SIZE_FOR_MODE (x), x_addr, 0, 1))
return 0;
if (aliases_everything_p (x))
@@ -2268,6 +2421,19 @@ write_dependence_p (rtx mem, rtx x, int writep)
if (GET_MODE (mem) == BLKmode && GET_CODE (XEXP (mem, 0)) == SCRATCH)
return 1;
+ /* APPLE LOCAL begin make SPEC gcc work with strict aliasing */
+ x_addr = get_addr (XEXP (x, 0));
+ mem_addr = get_addr (XEXP (mem, 0));
+
+ /* If two addresses are "the same" they conflict, even if type
+ checking says they don't. This is a bit too conservative
+ since there's no guarantee identical registers will have the
+ same values in both addresses. This is required to build
+ the (nonstandard) version of gcc found in SPEC. */
+ if (rtx_equal_p (x_addr, mem_addr))
+ return 1;
+ /* APPLE LOCAL end make SPEC gcc work with strict aliasing */
+
if (DIFFERENT_ALIAS_SETS_P (x, mem))
return 0;
@@ -2290,6 +2456,11 @@ write_dependence_p (rtx mem, rtx x, int writep)
return 0;
}
+ /* APPLE LOCAL begin aliasing improvement */
+ if (overlapping_memrefs_p (mem, x))
+ return 1;
+ /* APPLE LOCAL end */
+
if (! base_alias_check (x_addr, mem_addr, GET_MODE (x),
GET_MODE (mem)))
return 0;
@@ -2298,7 +2469,8 @@ write_dependence_p (rtx mem, rtx x, int writep)
mem_addr = canon_rtx (mem_addr);
if (!memrefs_conflict_p (SIZE_FOR_MODE (mem), mem_addr,
- SIZE_FOR_MODE (x), x_addr, 0))
+ /* APPLE LOCAL nop on true-dependence. */
+ SIZE_FOR_MODE (x), x_addr, 0, 1))
return 0;
fixed_scalar
generated by cgit v1.2.3 (git 2.25.1) at 2024-06-08 23:40:58 +0000