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re PR middle-end/33699 (missing optimization on const addr area store)

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PR middle-end/33699
	* target.h (struct gcc_target): Fix indentation.  Add
	const_anchor.
	* target-def.h (TARGET_CONST_ANCHOR): New macro.
	(TARGET_INITIALIZER): Use it.
	* cse.c (CHEAPER): Move it up to the other macros.
	(insert): Rename this ...
	(insert_with_costs): ... to this.  Add cost parameters.  Update
	function comment.
	(insert): New function.  Call insert_with_costs.
	(compute_const_anchors, insert_const_anchor, insert_const_anchors,
	find_reg_offset_for_const, try_const_anchors): New functions.
	(cse_insn): Call try_const_anchors.  Adjust cost of src_related
	when using a const-anchor.  Call insert_const_anchors.
	* config/mips/mips.c (mips_set_mips16_mode): Set
	targetm.const_anchor.
	* doc/tm.texi (Misc): Document TARGET_CONST_ANCHOR.

testsuite/
	* gcc.target/mips/const-anchor-1.c: New test.
	* gcc.target/mips/const-anchor-2.c: New test.

From-SVN: r147944
This commit is contained in:
Adam Nemet 2009-05-28 07:42:52 +00:00 committed by Adam Nemet
parent 51fb7760dd
commit 2c5bfdf70b
9 changed files with 303 additions and 12 deletions
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20
gcc/ChangeLog
View File

@ -1,3 +1,23 @@
2009-05-28 Adam Nemet <anemet@caviumnetworks.com>
PR middle-end/33699
* target.h (struct gcc_target): Fix indentation. Add
const_anchor.
* target-def.h (TARGET_CONST_ANCHOR): New macro.
(TARGET_INITIALIZER): Use it.
* cse.c (CHEAPER): Move it up to the other macros.
(insert): Rename this ...
(insert_with_costs): ... to this. Add cost parameters. Update
function comment.
(insert): New function. Call insert_with_costs.
(compute_const_anchors, insert_const_anchor, insert_const_anchors,
find_reg_offset_for_const, try_const_anchors): New functions.
(cse_insn): Call try_const_anchors. Adjust cost of src_related
when using a const-anchor. Call insert_const_anchors.
* config/mips/mips.c (mips_set_mips16_mode): Set
targetm.const_anchor.
* doc/tm.texi (Misc): Document TARGET_CONST_ANCHOR.
2009-05-28 Alexandre Oliva <aoliva@redhat.com>
* tree-inline.c (remap_decls): Enable nonlocalized variables

4
gcc/config/mips/mips.c
View File

@ -13928,6 +13928,8 @@ mips_set_mips16_mode (int mips16_p)
targetm.min_anchor_offset = 0;
targetm.max_anchor_offset = 127;
targetm.const_anchor = 0;
if (flag_pic && !TARGET_OLDABI)
sorry ("MIPS16 PIC for ABIs other than o32 and o64");
@ -13955,6 +13957,8 @@ mips_set_mips16_mode (int mips16_p)
targetm.min_anchor_offset = -32768;
targetm.max_anchor_offset = 32767;
targetm.const_anchor = 0x8000;
}
/* (Re)initialize MIPS target internals for new ISA. */

240
gcc/cse.c
View File

@ -502,6 +502,11 @@ struct table_elt
#define REGNO_QTY_VALID_P(N) (REG_QTY (N) >= 0)
/* Compare table_elt X and Y and return true iff X is cheaper than Y. */
#define CHEAPER(X, Y) \
(preferable ((X)->cost, (X)->regcost, (Y)->cost, (Y)->regcost) < 0)
static struct table_elt *table[HASH_SIZE];
/* Chain of `struct table_elt's made so far for this function
@ -563,6 +568,8 @@ static void remove_pseudo_from_table (rtx, unsigned);
static struct table_elt *lookup (rtx, unsigned, enum machine_mode);
static struct table_elt *lookup_for_remove (rtx, unsigned, enum machine_mode);
static rtx lookup_as_function (rtx, enum rtx_code);
static struct table_elt *insert_with_costs (rtx, struct table_elt *, unsigned,
enum machine_mode, int, int);
static struct table_elt *insert (rtx, struct table_elt *, unsigned,
enum machine_mode);
static void merge_equiv_classes (struct table_elt *, struct table_elt *);
@ -1213,6 +1220,174 @@ insert_regs (rtx x, struct table_elt *classp, int modified)
return mention_regs (x);
}
/* Compute upper and lower anchors for CST. Also compute the offset of CST
from these anchors/bases such that *_BASE + *_OFFS = CST. Return false iff
CST is equal to an anchor. */
static bool
compute_const_anchors (rtx cst,
HOST_WIDE_INT *lower_base, HOST_WIDE_INT *lower_offs,
HOST_WIDE_INT *upper_base, HOST_WIDE_INT *upper_offs)
{
HOST_WIDE_INT n = INTVAL (cst);
*lower_base = n & ~(targetm.const_anchor - 1);
if (*lower_base == n)
return false;
*upper_base =
(n + (targetm.const_anchor - 1)) & ~(targetm.const_anchor - 1);
*upper_offs = n - *upper_base;
*lower_offs = n - *lower_base;
return true;
}
/* Insert the equivalence between ANCHOR and (REG + OFF) in mode MODE. */
static void
insert_const_anchor (HOST_WIDE_INT anchor, rtx reg, HOST_WIDE_INT offs,
enum machine_mode mode)
{
struct table_elt *elt;
unsigned hash;
rtx anchor_exp;
rtx exp;
anchor_exp = GEN_INT (anchor);
hash = HASH (anchor_exp, mode);
elt = lookup (anchor_exp, hash, mode);
if (!elt)
elt = insert (anchor_exp, NULL, hash, mode);
exp = plus_constant (reg, offs);
/* REG has just been inserted and the hash codes recomputed. */
mention_regs (exp);
hash = HASH (exp, mode);
/* Use the cost of the register rather than the whole expression. When
looking up constant anchors we will further offset the corresponding
expression therefore it does not make sense to prefer REGs over
reg-immediate additions. Prefer instead the oldest expression. Also
don't prefer pseudos over hard regs so that we derive constants in
argument registers from other argument registers rather than from the
original pseudo that was used to synthesize the constant. */
insert_with_costs (exp, elt, hash, mode, COST (reg), 1);
}
/* The constant CST is equivalent to the register REG. Create
equivalences between the two anchors of CST and the corresponding
register-offset expressions using REG. */
static void
insert_const_anchors (rtx reg, rtx cst, enum machine_mode mode)
{
HOST_WIDE_INT lower_base, lower_offs, upper_base, upper_offs;
if (!compute_const_anchors (cst, &lower_base, &lower_offs,
&upper_base, &upper_offs))
return;
/* Ignore anchors of value 0. Constants accessible from zero are
simple. */
if (lower_base != 0)
insert_const_anchor (lower_base, reg, -lower_offs, mode);
if (upper_base != 0)
insert_const_anchor (upper_base, reg, -upper_offs, mode);
}
/* We need to express ANCHOR_ELT->exp + OFFS. Walk the equivalence list of
ANCHOR_ELT and see if offsetting any of the entries by OFFS would create a
valid expression. Return the cheapest and oldest of such expressions. In
*OLD, return how old the resulting expression is compared to the other
equivalent expressions. */
static rtx
find_reg_offset_for_const (struct table_elt *anchor_elt, HOST_WIDE_INT offs,
unsigned *old)
{
struct table_elt *elt;
unsigned idx;
struct table_elt *match_elt;
rtx match;
/* Find the cheapest and *oldest* expression to maximize the chance of
reusing the same pseudo. */
match_elt = NULL;
match = NULL_RTX;
for (elt = anchor_elt->first_same_value, idx = 0;
elt;
elt = elt->next_same_value, idx++)
{
if (match_elt && CHEAPER (match_elt, elt))
return match;
if (REG_P (elt->exp)
|| (GET_CODE (elt->exp) == PLUS
&& REG_P (XEXP (elt->exp, 0))
&& GET_CODE (XEXP (elt->exp, 1)) == CONST_INT))
{
rtx x;
/* Ignore expressions that are no longer valid. */
if (!REG_P (elt->exp) && !exp_equiv_p (elt->exp, elt->exp, 1, false))
continue;
x = plus_constant (elt->exp, offs);
if (REG_P (x)
|| (GET_CODE (x) == PLUS
&& IN_RANGE (INTVAL (XEXP (x, 1)),
-targetm.const_anchor,
targetm.const_anchor - 1)))
{
match = x;
match_elt = elt;
*old = idx;
}
}
}
return match;
}
/* Try to express the constant SRC_CONST using a register+offset expression
derived from a constant anchor. Return it if successful or NULL_RTX,
otherwise. */
static rtx
try_const_anchors (rtx src_const, enum machine_mode mode)
{
struct table_elt *lower_elt, *upper_elt;
HOST_WIDE_INT lower_base, lower_offs, upper_base, upper_offs;
rtx lower_anchor_rtx, upper_anchor_rtx;
rtx lower_exp = NULL_RTX, upper_exp = NULL_RTX;
unsigned lower_old, upper_old;
if (!compute_const_anchors (src_const, &lower_base, &lower_offs,
&upper_base, &upper_offs))
return NULL_RTX;
lower_anchor_rtx = GEN_INT (lower_base);
upper_anchor_rtx = GEN_INT (upper_base);
lower_elt = lookup (lower_anchor_rtx, HASH (lower_anchor_rtx, mode), mode);
upper_elt = lookup (upper_anchor_rtx, HASH (upper_anchor_rtx, mode), mode);
if (lower_elt)
lower_exp = find_reg_offset_for_const (lower_elt, lower_offs, &lower_old);
if (upper_elt)
upper_exp = find_reg_offset_for_const (upper_elt, upper_offs, &upper_old);
if (!lower_exp)
return upper_exp;
if (!upper_exp)
return lower_exp;
/* Return the older expression. */
return (upper_old > lower_old ? upper_exp : lower_exp);
}
/* Look in or update the hash table. */
/* Remove table element ELT from use in the table.
@ -1380,11 +1555,11 @@ lookup_as_function (rtx x, enum rtx_code code)
return 0;
}
/* Insert X in the hash table, assuming HASH is its hash code
and CLASSP is an element of the class it should go in
(or 0 if a new class should be made).
It is inserted at the proper position to keep the class in
the order cheapest first.
/* Insert X in the hash table, assuming HASH is its hash code and
CLASSP is an element of the class it should go in (or 0 if a new
class should be made). COST is the code of X and reg_cost is the
cost of registers in X. It is inserted at the proper position to
keep the class in the order cheapest first.
MODE is the machine-mode of X, or if X is an integer constant
with VOIDmode then MODE is the mode with which X will be used.
@ -1404,11 +1579,9 @@ lookup_as_function (rtx x, enum rtx_code code)
If necessary, update table showing constant values of quantities. */
#define CHEAPER(X, Y) \
(preferable ((X)->cost, (X)->regcost, (Y)->cost, (Y)->regcost) < 0)
static struct table_elt *
insert (rtx x, struct table_elt *classp, unsigned int hash, enum machine_mode mode)
insert_with_costs (rtx x, struct table_elt *classp, unsigned int hash,
enum machine_mode mode, int cost, int reg_cost)
{
struct table_elt *elt;
@ -1430,8 +1603,8 @@ insert (rtx x, struct table_elt *classp, unsigned int hash, enum machine_mode mo
elt->exp = x;
elt->canon_exp = NULL_RTX;
elt->cost = COST (x);
elt->regcost = approx_reg_cost (x);
elt->cost = cost;
elt->regcost = reg_cost;
elt->next_same_value = 0;
elt->prev_same_value = 0;
elt->next_same_hash = table[hash];
@ -1566,6 +1739,17 @@ insert (rtx x, struct table_elt *classp, unsigned int hash, enum machine_mode mo
return elt;
}
/* Wrap insert_with_costs by passing the default costs. */
static struct table_elt *
insert (rtx x, struct table_elt *classp, unsigned int hash,
enum machine_mode mode)
{
return
insert_with_costs (x, classp, hash, mode, COST (x), approx_reg_cost (x));
}
/* Given two equivalence classes, CLASS1 and CLASS2, put all the entries from
CLASS2 into CLASS1. This is done when we have reached an insn which makes
@ -4253,6 +4437,7 @@ cse_insn (rtx insn)
rtx src_eqv_here;
rtx src_const = 0;
rtx src_related = 0;
bool src_related_is_const_anchor = false;
struct table_elt *src_const_elt = 0;
int src_cost = MAX_COST;
int src_eqv_cost = MAX_COST;
@ -4602,6 +4787,19 @@ cse_insn (rtx insn)
}
#endif /* LOAD_EXTEND_OP */
/* Try to express the constant using a register+offset expression
derived from a constant anchor. */
if (targetm.const_anchor
&& !src_related
&& src_const
&& GET_CODE (src_const) == CONST_INT)
{
src_related = try_const_anchors (src_const, mode);
src_related_is_const_anchor = src_related != NULL_RTX;
}
if (src == src_folded)
src_folded = 0;
@ -4706,6 +4904,18 @@ cse_insn (rtx insn)
{
src_related_cost = COST (src_related);
src_related_regcost = approx_reg_cost (src_related);
/* If a const-anchor is used to synthesize a constant that
normally requires multiple instructions then slightly prefer
it over the original sequence. These instructions are likely
to become redundant now. We can't compare against the cost
of src_eqv_here because, on MIPS for example, multi-insn
constants have zero cost; they are assumed to be hoisted from
loops. */
if (src_related_is_const_anchor
&& src_related_cost == src_cost
&& src_eqv_here)
src_related_cost--;
}
}
@ -5440,6 +5650,14 @@ cse_insn (rtx insn)
elt = insert (dest, sets[i].src_elt,
sets[i].dest_hash, GET_MODE (dest));
/* If this is a constant, insert the constant anchors with the
equivalent register-offset expressions using register DEST. */
if (targetm.const_anchor
&& REG_P (dest)
&& SCALAR_INT_MODE_P (GET_MODE (dest))
&& GET_CODE (sets[i].src_elt->exp) == CONST_INT)
insert_const_anchors (dest, sets[i].src_elt->exp, GET_MODE (dest));
elt->in_memory = (MEM_P (sets[i].inner_dest)
&& !MEM_READONLY_P (sets[i].inner_dest));

18
gcc/doc/tm.texi
View File

@ -10852,3 +10852,21 @@ cannot safely move arguments from the registers in which they are passed
to the stack. Therefore, this hook should return true in general, but
false for naked functions. The default implementation always returns true.
@end deftypefn
@deftypevr {Target Hook} {unsigned HOST_WIDE_INT} TARGET_CONST_ANCHOR
On some architectures it can take multiple instructions to synthesize
a constant. If there is another constant already in a register that
is close enough in value then it is preferable that the new constant
is computed from this register using immediate addition or
substraction. We accomplish this through CSE. Besides the value of
the constant we also add a lower and an upper constant anchor to the
available expressions. These are then queried when encountering new
constants. The anchors are computed by rounding the constant up and
down to a multiple of the value of @code{TARGET_CONST_ANCHOR}.
@code{TARGET_CONST_ANCHOR} should be the maximum positive value
accepted by immediate-add plus one. We currently assume that the
value of @code{TARGET_CONST_ANCHOR} is a power of 2. For example, on
MIPS, where add-immediate takes a 16-bit signed value,
@code{TARGET_CONST_ANCHOR} is set to @samp{0x8000}. The default value
is zero, which disables this optimization. @end deftypevr

2
gcc/target-def.h
View File

@ -423,6 +423,7 @@
/* In cse.c. */
#define TARGET_ADDRESS_COST default_address_cost
#define TARGET_CONST_ANCHOR 0
/* In builtins.c. */
#define TARGET_INIT_BUILTINS hook_void_void
@ -922,6 +923,7 @@
TARGET_STACK_PROTECT_FAIL, \
TARGET_INVALID_WITHIN_DOLOOP, \
TARGET_VALID_DLLIMPORT_ATTRIBUTE_P, \
TARGET_CONST_ANCHOR, \
TARGET_CALLS, \
TARGET_INVALID_CONVERSION, \
TARGET_INVALID_UNARY_OP, \

6
gcc/target.h
View File

@ -481,7 +481,7 @@ struct gcc_target
/* Target builtin that implements vector permute. */
tree (* builtin_vec_perm) (tree, tree*);
} vectorize;
} vectorize;
/* The initial value of target_flags. */
int default_target_flags;
@ -825,6 +825,10 @@ struct gcc_target
checks to handle_dll_attribute (). */
bool (* valid_dllimport_attribute_p) (const_tree decl);
/* If non-zero, align constant anchors in CSE to a multiple of this
value. */
unsigned HOST_WIDE_INT const_anchor;
/* Functions relating to calls - argument passing, returns, etc. */
struct calls {
bool (*promote_function_args) (const_tree fntype);

6
gcc/testsuite/ChangeLog
View File

@ -1,3 +1,9 @@
2009-05-28 Adam Nemet <anemet@caviumnetworks.com>
PR middle-end/33699
* gcc.target/mips/const-anchor-1.c: New test.
* gcc.target/mips/const-anchor-2.c: New test.
2009-05-27 Jason Merrill <jason@redhat.com>
* g++.dg/cpp0x/initlist15.C: New.

10
gcc/testsuite/gcc.target/mips/const-anchor-1.c Normal file
View File

@ -0,0 +1,10 @@
/* Derive a constant (0x1233ffff) from an intermediate value
(0x1234000) used to build another constant. */
/* { dg-options "-O" } */
/* { dg-final { scan-assembler-not "0x12330000|305332224" } } */
/* { dg-final { scan-assembler "addiu\t\\\$5,\\\$\[0-9\]*,-1" } } */
NOMIPS16 void f ()
{
g (0x12340001, 0x1233ffff);
}

9
gcc/testsuite/gcc.target/mips/const-anchor-2.c Normal file
View File

@ -0,0 +1,9 @@
/* Derive a constant (0x30001) from another constant. */
/* { dg-options "-O" } */
/* { dg-final { scan-assembler-not "0x300000|196608" } } */
/* { dg-final { scan-assembler "addiu\t\\\$5,\\\$\[0-9\]*,32763" } } */
NOMIPS16 void f ()
{
g (0x28006, 0x30001);
}