This patch replaces the rtxes in mem_attrs with (bool, HOST_WIDE_INT) pairs.
There's already room for the bools in the padding after "addrspace".
(There's room for one more bool after this patch; we could move to
bitfields if more are needed.)
The new structure is 8 bytes bigger when using a combination of a 32-bit
host and a need_64bit_hwint target. In other cases it should be the same
as before, and will avoid some pointer chasing. The question is whether
that's an acceptable trade-off or not.
Richard
gcc/
* rtl.h (mem_attrs): Turn offset and size fields into HOST_WIDE_INTs.
Add offset_known_p and size_known_p fields.
(MEM_OFFSET_KNOWN_P): Update accordingly.
(MEM_OFFSET, MEM_SIZE_KNOWN_P, MEM_SIZE): Likewise.
* emit-rtl.c (mem_attrs_htab_hash): Update after mem_attrs changes.
(mem_attrs_eq_p, set_mem_attributes_minus_bitpos, set_mem_offset)
(clear_mem_offset, set_mem_size, clear_mem_size, change_address)
(adjust_address_1, widen_memory_access, set_mem_attrs_for_spill)
(init_emit_regs): Likewise.
Index: gcc/rtl.h
===================================================================
--- gcc/rtl.h 2011-07-17 11:40:14.000000000 +0100
+++ gcc/rtl.h 2011-07-17 11:40:18.000000000 +0100
@@ -136,19 +136,38 @@ typedef struct
/* Structure used to describe the attributes of a MEM. These are hashed
so MEMs that the same attributes share a data structure. This means
- they cannot be modified in place. If any element is nonzero, it means
- the value of the corresponding attribute is unknown. */
-/* ALIGN and SIZE are the alignment and size of the MEM itself,
- while EXPR can describe a larger underlying object, which might have a
- stricter alignment; OFFSET is the offset of the MEM within that object. */
+ they cannot be modified in place. */
typedef struct GTY(()) mem_attrs
{
- tree expr; /* expr corresponding to MEM. */
- rtx offset; /* Offset from start of DECL, as CONST_INT. */
- rtx size; /* Size in bytes, as a CONST_INT. */
- alias_set_type alias; /* Memory alias set. */
- unsigned int align; /* Alignment of MEM in bits. */
- unsigned char addrspace; /* Address space (0 for generic). */
+ /* The expression that the MEM accesses, or null if not known.
+ This expression might be larger than the memory reference itself.
+ (In other words, the MEM might access only part of the object.) */
+ tree expr;
+
+ /* The offset of the memory reference from the start of EXPR.
+ Only valid if OFFSET_KNOWN_P. */
+ HOST_WIDE_INT offset;
+
+ /* The size of the memory reference in bytes. Only valid if
+ SIZE_KNOWN_P. */
+ HOST_WIDE_INT size;
+
+ /* The alias set of the memory reference. */
+ alias_set_type alias;
+
+ /* The alignment of the reference in bits. Always a multiple of
+ BITS_PER_UNIT. Note that EXPR may have a stricter alignment
+ than the memory reference itself. */
+ unsigned int align;
+
+ /* The address space that the memory reference uses. */
+ unsigned char addrspace;
+
+ /* True if OFFSET is known. */
+ bool offset_known_p;
+
+ /* True if SIZE is known. */
+ bool size_known_p;
} mem_attrs;
/* Structure used to describe the attributes of a REG in similar way as
@@ -1303,19 +1322,19 @@ #define MEM_ALIAS_SET(RTX) (get_mem_attr
#define MEM_EXPR(RTX) (get_mem_attrs (RTX)->expr)
/* For a MEM rtx, true if its MEM_OFFSET is known. */
-#define MEM_OFFSET_KNOWN_P(RTX) (get_mem_attrs (RTX)->offset != NULL_RTX)
+#define MEM_OFFSET_KNOWN_P(RTX) (get_mem_attrs (RTX)->offset_known_p)
/* For a MEM rtx, the offset from the start of MEM_EXPR. */
-#define MEM_OFFSET(RTX) INTVAL (get_mem_attrs (RTX)->offset)
+#define MEM_OFFSET(RTX) (get_mem_attrs (RTX)->offset)
/* For a MEM rtx, the address space. */
#define MEM_ADDR_SPACE(RTX) (get_mem_attrs (RTX)->addrspace)
/* For a MEM rtx, true if its MEM_SIZE is known. */
-#define MEM_SIZE_KNOWN_P(RTX) (get_mem_attrs (RTX)->size != NULL_RTX)
+#define MEM_SIZE_KNOWN_P(RTX) (get_mem_attrs (RTX)->size_known_p)
/* For a MEM rtx, the size in bytes of the MEM. */
-#define MEM_SIZE(RTX) INTVAL (get_mem_attrs (RTX)->size)
+#define MEM_SIZE(RTX) (get_mem_attrs (RTX)->size)
/* For a MEM rtx, the alignment in bits. We can use the alignment of the
mode as a default when STRICT_ALIGNMENT, but not if not. */
Index: gcc/emit-rtl.c
===================================================================
--- gcc/emit-rtl.c 2011-07-17 11:40:14.000000000 +0100
+++ gcc/emit-rtl.c 2011-07-17 11:40:18.000000000 +0100
@@ -256,8 +256,8 @@ mem_attrs_htab_hash (const void *x)
return (p->alias ^ (p->align * 1000)
^ (p->addrspace * 4000)
- ^ ((p->offset ? INTVAL (p->offset) : 0) * 50000)
- ^ ((p->size ? INTVAL (p->size) : 0) * 2500000)
+ ^ ((p->offset_known_p ? p->offset : 0) * 50000)
+ ^ ((p->size_known_p ? p->size : 0) * 2500000)
^ (size_t) iterative_hash_expr (p->expr, 0));
}
@@ -266,8 +266,12 @@ mem_attrs_htab_hash (const void *x)
static bool
mem_attrs_eq_p (const struct mem_attrs *p, const struct mem_attrs *q)
{
- return (p->alias == q->alias && p->offset == q->offset
- && p->size == q->size && p->align == q->align
+ return (p->alias == q->alias
+ && p->offset_known_p == q->offset_known_p
+ && (!p->offset_known_p || p->offset == q->offset)
+ && p->size_known_p == q->size_known_p
+ && (!p->size_known_p || p->size == q->size)
+ && p->align == q->align
&& p->addrspace == q->addrspace
&& (p->expr == q->expr
|| (p->expr != NULL_TREE && q->expr != NULL_TREE
@@ -1585,7 +1589,9 @@ set_mem_attributes_minus_bitpos (rtx ref
/* ??? Can this ever happen? Calling this routine on a MEM that
already carries memory attributes should probably be invalid. */
attrs.expr = refattrs->expr;
+ attrs.offset_known_p = refattrs->offset_known_p;
attrs.offset = refattrs->offset;
+ attrs.size_known_p = refattrs->size_known_p;
attrs.size = refattrs->size;
attrs.align = refattrs->align;
}
@@ -1595,9 +1601,10 @@ set_mem_attributes_minus_bitpos (rtx ref
{
defattrs = mode_mem_attrs[(int) GET_MODE (ref)];
gcc_assert (!defattrs->expr);
- gcc_assert (!defattrs->offset);
+ gcc_assert (!defattrs->offset_known_p);
/* Respect mode size. */
+ attrs.size_known_p = defattrs->size_known_p;
attrs.size = defattrs->size;
/* ??? Is this really necessary? We probably should always get
the size from the type below. */
@@ -1656,7 +1663,10 @@ set_mem_attributes_minus_bitpos (rtx ref
/* If the size is known, we can set that. */
if (TYPE_SIZE_UNIT (type) && host_integerp (TYPE_SIZE_UNIT (type), 1))
- attrs.size = GEN_INT (tree_low_cst (TYPE_SIZE_UNIT (type), 1));
+ {
+ attrs.size_known_p = true;
+ attrs.size = tree_low_cst (TYPE_SIZE_UNIT (type), 1);
+ }
/* If T is not a type, we may be able to deduce some more information about
the expression. */
@@ -1694,11 +1704,16 @@ set_mem_attributes_minus_bitpos (rtx ref
if (DECL_P (t))
{
attrs.expr = t;
- attrs.offset = const0_rtx;
+ attrs.offset_known_p = true;
+ attrs.offset = 0;
apply_bitpos = bitpos;
- attrs.size = (DECL_SIZE_UNIT (t)
- && host_integerp (DECL_SIZE_UNIT (t), 1)
- ? GEN_INT (tree_low_cst (DECL_SIZE_UNIT (t), 1)) : 0);
+ if (DECL_SIZE_UNIT (t) && host_integerp (DECL_SIZE_UNIT (t), 1))
+ {
+ attrs.size_known_p = true;
+ attrs.size = tree_low_cst (DECL_SIZE_UNIT (t), 1);
+ }
+ else
+ attrs.size_known_p = false;
attrs.align = DECL_ALIGN (t);
align_computed = true;
}
@@ -1721,7 +1736,8 @@ set_mem_attributes_minus_bitpos (rtx ref
&& ! DECL_BIT_FIELD (TREE_OPERAND (t, 1)))
{
attrs.expr = t;
- attrs.offset = const0_rtx;
+ attrs.offset_known_p = true;
+ attrs.offset = 0;
apply_bitpos = bitpos;
/* ??? Any reason the field size would be different than
the size we got from the type? */
@@ -1762,7 +1778,7 @@ set_mem_attributes_minus_bitpos (rtx ref
if (DECL_P (t2))
{
attrs.expr = t2;
- attrs.offset = NULL;
+ attrs.offset_known_p = false;
if (host_integerp (off_tree, 1))
{
HOST_WIDE_INT ioff = tree_low_cst (off_tree, 1);
@@ -1771,17 +1787,19 @@ set_mem_attributes_minus_bitpos (rtx ref
if (aoff && (unsigned HOST_WIDE_INT) aoff < attrs.align)
attrs.align = aoff;
align_computed = true;
- attrs.offset = GEN_INT (ioff);
+ attrs.offset_known_p = true;
+ attrs.offset = ioff;
apply_bitpos = bitpos;
}
}
else if (TREE_CODE (t2) == COMPONENT_REF)
{
attrs.expr = t2;
- attrs.offset = NULL;
+ attrs.offset_known_p = false;
if (host_integerp (off_tree, 1))
{
- attrs.offset = GEN_INT (tree_low_cst (off_tree, 1));
+ attrs.offset_known_p = true;
+ attrs.offset = tree_low_cst (off_tree, 1);
apply_bitpos = bitpos;
}
/* ??? Any reason the field size would be different than
@@ -1792,7 +1810,8 @@ set_mem_attributes_minus_bitpos (rtx ref
else if (TREE_CODE (t) == MEM_REF)
{
attrs.expr = t;
- attrs.offset = const0_rtx;
+ attrs.offset_known_p = true;
+ attrs.offset = 0;
apply_bitpos = bitpos;
}
}
@@ -1802,7 +1821,8 @@ set_mem_attributes_minus_bitpos (rtx ref
|| TREE_CODE (t) == TARGET_MEM_REF)
{
attrs.expr = t;
- attrs.offset = const0_rtx;
+ attrs.offset_known_p = true;
+ attrs.offset = 0;
apply_bitpos = bitpos;
}
@@ -1818,10 +1838,10 @@ set_mem_attributes_minus_bitpos (rtx ref
object to contain the negative offset. */
if (apply_bitpos)
{
- attrs.offset = plus_constant (attrs.offset,
- -(apply_bitpos / BITS_PER_UNIT));
- if (attrs.size)
- attrs.size = plus_constant (attrs.size, apply_bitpos / BITS_PER_UNIT);
+ gcc_assert (attrs.offset_known_p);
+ attrs.offset -= apply_bitpos / BITS_PER_UNIT;
+ if (attrs.size_known_p)
+ attrs.size += apply_bitpos / BITS_PER_UNIT;
}
/* Now set the attributes we computed above. */
@@ -1903,7 +1923,8 @@ set_mem_offset (rtx mem, HOST_WIDE_INT o
struct mem_attrs attrs;
attrs = *get_mem_attrs (mem);
- attrs.offset = GEN_INT (offset);
+ attrs.offset_known_p = true;
+ attrs.offset = offset;
set_mem_attrs (mem, &attrs);
}
@@ -1915,7 +1936,7 @@ clear_mem_offset (rtx mem)
struct mem_attrs attrs;
attrs = *get_mem_attrs (mem);
- attrs.offset = NULL_RTX;
+ attrs.offset_known_p = false;
set_mem_attrs (mem, &attrs);
}
@@ -1927,7 +1948,8 @@ set_mem_size (rtx mem, HOST_WIDE_INT siz
struct mem_attrs attrs;
attrs = *get_mem_attrs (mem);
- attrs.size = GEN_INT (size);
+ attrs.size_known_p = true;
+ attrs.size = size;
set_mem_attrs (mem, &attrs);
}
@@ -1939,7 +1961,7 @@ clear_mem_size (rtx mem)
struct mem_attrs attrs;
attrs = *get_mem_attrs (mem);
- attrs.size = NULL_RTX;
+ attrs.size_known_p = false;
set_mem_attrs (mem, &attrs);
}
@@ -1993,8 +2015,9 @@ change_address (rtx memref, enum machine
attrs = *get_mem_attrs (memref);
defattrs = mode_mem_attrs[(int) mmode];
- attrs.expr = defattrs->expr;
- attrs.offset = defattrs->offset;
+ attrs.expr = NULL_TREE;
+ attrs.offset_known_p = false;
+ attrs.size_known_p = defattrs->size_known_p;
attrs.size = defattrs->size;
attrs.align = defattrs->align;
@@ -2076,8 +2099,8 @@ adjust_address_1 (rtx memref, enum machi
/* Compute the new values of the memory attributes due to this adjustment.
We add the offsets and update the alignment. */
- if (attrs.offset)
- attrs.offset = GEN_INT (offset + INTVAL (attrs.offset));
+ if (attrs.offset_known_p)
+ attrs.offset += offset;
/* Compute the new alignment by taking the MIN of the alignment and the
lowest-order set bit in OFFSET, but don't change the alignment if OFFSET
@@ -2090,10 +2113,13 @@ adjust_address_1 (rtx memref, enum machi
/* We can compute the size in a number of ways. */
defattrs = mode_mem_attrs[(int) GET_MODE (new_rtx)];
- if (defattrs->size)
- attrs.size = defattrs->size;
- else if (attrs.size)
- attrs.size = plus_constant (attrs.size, -offset);
+ if (defattrs->size_known_p)
+ {
+ attrs.size_known_p = true;
+ attrs.size = defattrs->size;
+ }
+ else if (attrs.size_known_p)
+ attrs.size -= offset;
set_mem_attrs (new_rtx, &attrs);
@@ -2124,7 +2150,7 @@ offset_address (rtx memref, rtx offset,
{
rtx new_rtx, addr = XEXP (memref, 0);
enum machine_mode address_mode;
- struct mem_attrs attrs;
+ struct mem_attrs attrs, *defattrs;
attrs = *get_mem_attrs (memref);
address_mode = targetm.addr_space.address_mode (attrs.addrspace);
@@ -2155,8 +2181,10 @@ offset_address (rtx memref, rtx offset,
/* Update the alignment to reflect the offset. Reset the offset, which
we don't know. */
- attrs.offset = 0;
- attrs.size = mode_mem_attrs[(int) GET_MODE (new_rtx)]->size;
+ defattrs = mode_mem_attrs[(int) GET_MODE (new_rtx)];
+ attrs.offset_known_p = false;
+ attrs.size_known_p = defattrs->size_known_p;
+ attrs.size = defattrs->size;
attrs.align = MIN (attrs.align, pow2 * BITS_PER_UNIT);
set_mem_attrs (new_rtx, &attrs);
return new_rtx;
@@ -2204,7 +2232,7 @@ widen_memory_access (rtx memref, enum ma
/* If we don't know what offset we were at within the expression, then
we can't know if we've overstepped the bounds. */
- if (! attrs.offset)
+ if (! attrs.offset_known_p)
attrs.expr = NULL_TREE;
while (attrs.expr)
@@ -2224,7 +2252,7 @@ widen_memory_access (rtx memref, enum ma
otherwise strip back to the containing structure. */
if (TREE_CODE (DECL_SIZE_UNIT (field)) == INTEGER_CST
&& compare_tree_int (DECL_SIZE_UNIT (field), size) >= 0
- && INTVAL (attrs.offset) >= 0)
+ && attrs.offset >= 0)
break;
if (! host_integerp (offset, 1))
@@ -2234,18 +2262,16 @@ widen_memory_access (rtx memref, enum ma
}
attrs.expr = TREE_OPERAND (attrs.expr, 0);
- attrs.offset
- = (GEN_INT (INTVAL (attrs.offset)
- + tree_low_cst (offset, 1)
- + (tree_low_cst (DECL_FIELD_BIT_OFFSET (field), 1)
- / BITS_PER_UNIT)));
+ attrs.offset += tree_low_cst (offset, 1);
+ attrs.offset += (tree_low_cst (DECL_FIELD_BIT_OFFSET (field), 1)
+ / BITS_PER_UNIT);
}
/* Similarly for the decl. */
else if (DECL_P (attrs.expr)
&& DECL_SIZE_UNIT (attrs.expr)
&& TREE_CODE (DECL_SIZE_UNIT (attrs.expr)) == INTEGER_CST
&& compare_tree_int (DECL_SIZE_UNIT (attrs.expr), size) >= 0
- && (! attrs.offset || INTVAL (attrs.offset) >= 0))
+ && (! attrs.offset_known_p || attrs.offset >= 0))
break;
else
{
@@ -2257,12 +2283,13 @@ widen_memory_access (rtx memref, enum ma
}
if (! attrs.expr)
- attrs.offset = NULL_RTX;
+ attrs.offset_known_p = false;
/* The widened memory may alias other stuff, so zap the alias set. */
/* ??? Maybe use get_alias_set on any remaining expression. */
attrs.alias = 0;
- attrs.size = GEN_INT (size);
+ attrs.size_known_p = true;
+ attrs.size = size;
set_mem_attrs (new_rtx, &attrs);
return new_rtx;
}
@@ -2319,10 +2346,11 @@ set_mem_attrs_for_spill (rtx mem)
(mem:MODE (plus (reg sfp) (const_int offset)))
with perhaps the plus missing for offset = 0. */
addr = XEXP (mem, 0);
- attrs.offset = const0_rtx;
+ attrs.offset_known_p = true;
+ attrs.offset = 0;
if (GET_CODE (addr) == PLUS
&& CONST_INT_P (XEXP (addr, 1)))
- attrs.offset = XEXP (addr, 1);
+ attrs.offset = INTVAL (XEXP (addr, 1));
set_mem_attrs (mem, &attrs);
MEM_NOTRAP_P (mem) = 1;
@@ -5522,7 +5550,8 @@ init_emit_regs (void)
attrs->addrspace = ADDR_SPACE_GENERIC;
if (mode != BLKmode)
{
- attrs->size = GEN_INT (GET_MODE_SIZE (mode));
+ attrs->size_known_p = true;
+ attrs->size = GET_MODE_SIZE (mode);
if (STRICT_ALIGNMENT)
attrs->align = GET_MODE_ALIGNMENT (mode);
}
