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calls.c (expand_call): Reorganize somewhat in order to avoid unnecesary recalculation inside loop and...

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* calls.c (expand_call): Reorganize somewhat in order
	to avoid unnecesary recalculation inside loop and make
	tail call failure code cleaner.

From-SVN: r33798
This commit is contained in:
Jan Hubicka 2000-05-09 14:33:41 +00:00 committed by Jan Hubicka
parent f8cd412619
commit 4d393a0b06
2 changed files with 259 additions and 226 deletions
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6
gcc/ChangeLog
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@ -1,3 +1,9 @@
Tue May 9 16:30:27 MET DST 2000 Jan Hubicka <jh@suse.cz>
* calls.c (expand_call): Reorganize somewhat in order
to avoid unnecesary recalculation inside loop and make
tail call failure code cleaner.
Tue May 9 06:30:20 2000 Richard Kenner <kenner@vlsi1.ultra.nyu.edu>
* alias.c (nonlocal_reference_p): Minor reformatting.

479
gcc/calls.c
View File

@ -1946,7 +1946,8 @@ expand_call (exp, target, ignore)
tree fndecl = 0;
char *name = 0;
rtx insn;
int try_tail_call;
int try_tail_call = 1;
int try_tail_recursion = 1;
int pass;
/* Register in which non-BLKmode value will be returned,
@ -2162,7 +2163,135 @@ expand_call (exp, target, ignore)
return temp;
}
currently_expanding_call++;
if (fndecl && DECL_NAME (fndecl))
name = IDENTIFIER_POINTER (DECL_NAME (fndecl));
/* Figure out the amount to which the stack should be aligned. */
#ifdef PREFERRED_STACK_BOUNDARY
preferred_stack_boundary = PREFERRED_STACK_BOUNDARY;
#else
preferred_stack_boundary = STACK_BOUNDARY;
#endif
/* Operand 0 is a pointer-to-function; get the type of the function. */
funtype = TREE_TYPE (TREE_OPERAND (exp, 0));
if (! POINTER_TYPE_P (funtype))
abort ();
funtype = TREE_TYPE (funtype);
/* See if this is a call to a function that can return more than once
or a call to longjmp or malloc. */
flags |= special_function_p (fndecl, flags);
if (flags & ECF_MAY_BE_ALLOCA)
current_function_calls_alloca = 1;
/* If struct_value_rtx is 0, it means pass the address
as if it were an extra parameter. */
if (structure_value_addr && struct_value_rtx == 0)
{
/* If structure_value_addr is a REG other than
virtual_outgoing_args_rtx, we can use always use it. If it
is not a REG, we must always copy it into a register.
If it is virtual_outgoing_args_rtx, we must copy it to another
register in some cases. */
rtx temp = (GET_CODE (structure_value_addr) != REG
|| (ACCUMULATE_OUTGOING_ARGS
&& stack_arg_under_construction
&& structure_value_addr == virtual_outgoing_args_rtx)
? copy_addr_to_reg (structure_value_addr)
: structure_value_addr);
actparms
= tree_cons (error_mark_node,
make_tree (build_pointer_type (TREE_TYPE (funtype)),
temp),
actparms);
structure_value_addr_parm = 1;
}
/* Count the arguments and set NUM_ACTUALS. */
for (p = actparms, num_actuals = 0; p; p = TREE_CHAIN (p))
num_actuals++;
/* Compute number of named args.
Normally, don't include the last named arg if anonymous args follow.
We do include the last named arg if STRICT_ARGUMENT_NAMING is nonzero.
(If no anonymous args follow, the result of list_length is actually
one too large. This is harmless.)
If PRETEND_OUTGOING_VARARGS_NAMED is set and STRICT_ARGUMENT_NAMING is
zero, this machine will be able to place unnamed args that were
passed in registers into the stack. So treat all args as named.
This allows the insns emitting for a specific argument list to be
independent of the function declaration.
If PRETEND_OUTGOING_VARARGS_NAMED is not set, we do not have any
reliable way to pass unnamed args in registers, so we must force
them into memory. */
if ((STRICT_ARGUMENT_NAMING
|| ! PRETEND_OUTGOING_VARARGS_NAMED)
&& TYPE_ARG_TYPES (funtype) != 0)
n_named_args
= (list_length (TYPE_ARG_TYPES (funtype))
/* Don't include the last named arg. */
- (STRICT_ARGUMENT_NAMING ? 0 : 1)
/* Count the struct value address, if it is passed as a parm. */
+ structure_value_addr_parm);
else
/* If we know nothing, treat all args as named. */
n_named_args = num_actuals;
/* Start updating where the next arg would go.
On some machines (such as the PA) indirect calls have a different
calling convention than normal calls. The last argument in
INIT_CUMULATIVE_ARGS tells the backend if this is an indirect call
or not. */
INIT_CUMULATIVE_ARGS (args_so_far, funtype, NULL_RTX, (fndecl == 0));
/* Make a vector to hold all the information about each arg. */
args = (struct arg_data *) alloca (num_actuals
* sizeof (struct arg_data));
bzero ((char *) args, num_actuals * sizeof (struct arg_data));
/* Build up entries inthe ARGS array, compute the size of the arguments
into ARGS_SIZE, etc. */
initialize_argument_information (num_actuals, args, &args_size,
n_named_args, actparms, fndecl,
&args_so_far, reg_parm_stack_space,
&old_stack_level, &old_pending_adj,
&must_preallocate, &flags);
if (args_size.var)
{
/* If this function requires a variable-sized argument list, don't
try to make a cse'able block for this call. We may be able to
do this eventually, but it is too complicated to keep track of
what insns go in the cse'able block and which don't. */
flags &= ~(ECF_CONST | ECF_PURE);
must_preallocate = 1;
}
/* Now make final decision about preallocating stack space. */
must_preallocate = finalize_must_preallocate (must_preallocate,
num_actuals, args,
&args_size);
/* If the structure value address will reference the stack pointer, we
must stabilize it. We don't need to do this if we know that we are
not going to adjust the stack pointer in processing this call. */
if (structure_value_addr
&& (reg_mentioned_p (virtual_stack_dynamic_rtx, structure_value_addr)
|| reg_mentioned_p (virtual_outgoing_args_rtx,
structure_value_addr))
&& (args_size.var
|| (!ACCUMULATE_OUTGOING_ARGS && args_size.constant)))
structure_value_addr = copy_to_reg (structure_value_addr);
/* Tail calls can make things harder to debug, and we're traditionally
pushed these optimizations into -O2. Don't try if we're already
@ -2176,15 +2305,58 @@ expand_call (exp, target, ignore)
This is most often true of sjlj-exceptions, which we couldn't
tail-call to anyway. */
try_tail_call = 0;
if (flag_optimize_sibling_calls
&& currently_expanding_call == 1
&& rtx_equal_function_value_matters
&& stmt_loop_nest_empty ()
&& ! any_pending_cleanups (1))
{
tree new_actparms = NULL_TREE;
if (!flag_optimize_sibling_calls
|| !rtx_equal_function_value_matters
|| currently_expanding_call
|| !stmt_loop_nest_empty ()
|| any_pending_cleanups (1)
|| args_size.var)
try_tail_call = try_tail_recursion = 0;
/* Tail recursion fails, when we are not dealing with recursive calls. */
if (!try_tail_recursion
|| TREE_CODE (TREE_OPERAND (exp, 0)) != ADDR_EXPR
|| TREE_OPERAND (TREE_OPERAND (exp, 0), 0) != current_function_decl)
try_tail_recursion = 0;
/* Rest of purposes for tail call optimizations to fail. */
if (
#ifdef HAVE_sibcall_epilogue
!HAVE_sibcall_epilogue
#else
1
#endif
|| !try_tail_call
/* Doing sibling call optimization needs some work, since
structure_value_addr can be allocated on the stack.
It does not seem worth the effort since few optimizable
sibling calls will return a structure. */
|| structure_value_addr != NULL_RTX
/* If the register holding the address is a callee saved
register, then we lose. We have no way to prevent that,
so we only allow calls to named functions. */
/* ??? This could be done by having the insn constraints
use a register class that is all call-clobbered. Any
reload insns generated to fix things up would appear
before the sibcall_epilogue. */
|| fndecl == NULL_TREE
|| (flags & (ECF_RETURNS_TWICE | ECF_LONGJMP))
|| !FUNCTION_OK_FOR_SIBCALL (fndecl)
/* If this function requires more stack slots than the current
function, we cannot change it into a sibling call. */
|| args_size.constant > current_function_args_size
/* If the callee pops its own arguments, then it must pop exactly
the same number of arguments as the current function. */
|| RETURN_POPS_ARGS (fndecl, funtype, args_size.constant)
!= RETURN_POPS_ARGS (current_function_decl,
TREE_TYPE (current_function_decl),
current_function_args_size))
try_tail_call = 0;
if (try_tail_call || try_tail_recursion)
{
int end, inc;
actparms = NULL_TREE;
/* Ok, we're going to give the tail call the old college try.
This means we're going to evaluate the function arguments
up to three times. There are two degrees of badness we can
@ -2194,49 +2366,64 @@ expand_call (exp, target, ignore)
Generate a new argument list. Pass safe arguments through
unchanged. For the easy badness wrap them in UNSAVE_EXPRs.
For hard badness, evaluate them now and put their resulting
rtx in a temporary VAR_DECL. */
rtx in a temporary VAR_DECL.
for (p = actparms; p; p = TREE_CHAIN (p))
switch (unsafe_for_reeval (TREE_VALUE (p)))
{
case 0: /* Safe. */
new_actparms = tree_cons (TREE_PURPOSE (p), TREE_VALUE (p),
new_actparms);
break;
initialize_argument_information has ordered the array for the
order to be pushed, and we must remember this when reconstructing
the original argument orde. */
case 1: /* Mildly unsafe. */
new_actparms = tree_cons (TREE_PURPOSE (p),
unsave_expr (TREE_VALUE (p)),
new_actparms);
break;
if (PUSH_ARGS_REVERSED)
{
inc = 1;
i = 0;
end = num_actuals;
}
else
{
inc = -1;
i = num_actuals - 1;
end = -1;
}
case 2: /* Wildly unsafe. */
for (; i != end; i += inc)
{
switch (unsafe_for_reeval (args[i].tree_value))
{
tree var = build_decl (VAR_DECL, NULL_TREE,
TREE_TYPE (TREE_VALUE (p)));
DECL_RTL (var) = expand_expr (TREE_VALUE (p), NULL_RTX,
VOIDmode, EXPAND_NORMAL);
new_actparms = tree_cons (TREE_PURPOSE (p), var, new_actparms);
case 0: /* Safe. */
break;
case 1: /* Mildly unsafe. */
args[i].tree_value = unsave_expr (args[i].tree_value);
break;
case 2: /* Wildly unsafe. */
{
tree var = build_decl (VAR_DECL, NULL_TREE,
TREE_TYPE (args[i].tree_value));
DECL_RTL (var) = expand_expr (args[i].tree_value, NULL_RTX,
VOIDmode, EXPAND_NORMAL);
args[i].tree_value = var;
}
break;
default:
abort ();
}
break;
default:
abort ();
}
/* We built the new argument chain backwards. */
actparms = nreverse (new_actparms);
/* We need to build actparms for optimize_tail_recursion. We can
safely trash away TREE_PURPOSE, since it is unused by this
function. */
if (try_tail_recursion)
actparms = tree_cons (NULL_TREE, args[i].tree_value, actparms);
}
/* Expanding one of those dangerous arguments could have added
cleanups, but otherwise give it a whirl. */
try_tail_call = ! any_pending_cleanups (1);
if (any_pending_cleanups (1))
try_tail_call = try_tail_recursion = 0;
}
/* Generate a tail recursion sequence when calling ourselves. */
if (try_tail_call
&& TREE_CODE (TREE_OPERAND (exp, 0)) == ADDR_EXPR
&& TREE_OPERAND (TREE_OPERAND (exp, 0), 0) == current_function_decl)
if (try_tail_recursion)
{
/* We want to emit any pending stack adjustments before the tail
recursion "call". That way we know any adjustment after the tail
@ -2251,9 +2438,6 @@ expand_call (exp, target, ignore)
complete. */
start_sequence ();
/* Emit the pending stack adjustments before we expand any arguments. */
do_pending_stack_adjust ();
if (optimize_tail_recursion (actparms, get_last_insn ()))
tail_recursion_insns = get_insns ();
end_sequence ();
@ -2264,18 +2448,20 @@ expand_call (exp, target, ignore)
stack_pointer_delta = save_stack_pointer_delta;
}
function_call_count++;
currently_expanding_call++;
if (fndecl && DECL_NAME (fndecl))
name = IDENTIFIER_POINTER (DECL_NAME (fndecl));
if (profile_arc_flag && (flags & ECF_FORK_OR_EXEC))
{
/* A fork duplicates the profile information, and an exec discards
it. We can't rely on fork/exec to be paired. So write out the
profile information we have gathered so far, and clear it. */
/* ??? When Linux's __clone is called with CLONE_VM set, profiling
is subject to race conditions, just as with multithreaded
programs. */
/* Figure out the amount to which the stack should be aligned. */
#ifdef PREFERRED_STACK_BOUNDARY
preferred_stack_boundary = PREFERRED_STACK_BOUNDARY;
#else
preferred_stack_boundary = STACK_BOUNDARY;
#endif
preferred_unit_stack_boundary = preferred_stack_boundary / BITS_PER_UNIT;
emit_library_call (gen_rtx_SYMBOL_REF (Pmode, "__bb_fork_func"), 0,
VOIDmode, 0);
}
/* Ensure current function's preferred stack boundary is at least
what we need. We don't have to increase alignment for recursive
@ -2284,18 +2470,9 @@ expand_call (exp, target, ignore)
&& fndecl != current_function_decl)
cfun->preferred_stack_boundary = preferred_stack_boundary;
/* See if this is a call to a function that can return more than once
or a call to longjmp or malloc. */
flags |= special_function_p (fndecl, flags);
preferred_unit_stack_boundary = preferred_stack_boundary / BITS_PER_UNIT;
if (flags & ECF_MAY_BE_ALLOCA)
current_function_calls_alloca = 1;
/* Operand 0 is a pointer-to-function; get the type of the function. */
funtype = TREE_TYPE (TREE_OPERAND (exp, 0));
if (! POINTER_TYPE_P (funtype))
abort ();
funtype = TREE_TYPE (funtype);
function_call_count++;
/* We want to make two insn chains; one for a sibling call, the other
for a normal call. We will select one of the two chains after
@ -2314,27 +2491,7 @@ expand_call (exp, target, ignore)
if (pass == 0)
{
/* Various reasons we can not use a sibling call. */
if (! try_tail_call
#ifdef HAVE_sibcall_epilogue
|| ! HAVE_sibcall_epilogue
#else
|| 1
#endif
/* The structure value address is used and modified in the
loop below. It does not seem worth the effort to save and
restore it as a state variable since few optimizable
sibling calls will return a structure. */
|| structure_value_addr != NULL_RTX
/* If the register holding the address is a callee saved
register, then we lose. We have no way to prevent that,
so we only allow calls to named functions. */
/* ??? This could be done by having the insn constraints
use a register class that is all call-clobbered. Any
reload insns generated to fix things up would appear
before the sibcall_epilogue. */
|| fndecl == NULL_TREE
|| ! FUNCTION_OK_FOR_SIBCALL (fndecl))
if (! try_tail_call)
continue;
/* Emit any queued insns now; otherwise they would end up in
@ -2382,152 +2539,15 @@ expand_call (exp, target, ignore)
|| pass == 0)
do_pending_stack_adjust ();
if (profile_arc_flag && (flags & ECF_FORK_OR_EXEC))
{
/* A fork duplicates the profile information, and an exec discards
it. We can't rely on fork/exec to be paired. So write out the
profile information we have gathered so far, and clear it. */
/* ??? When Linux's __clone is called with CLONE_VM set, profiling
is subject to race conditions, just as with multithreaded
programs. */
emit_library_call (gen_rtx_SYMBOL_REF (Pmode, "__bb_fork_func"), 0,
VOIDmode, 0);
}
/* Push the temporary stack slot level so that we can free any
temporaries we make. */
push_temp_slots ();
/* Start updating where the next arg would go.
On some machines (such as the PA) indirect calls have a different
calling convention than normal calls. The last argument in
INIT_CUMULATIVE_ARGS tells the backend if this is an indirect call
or not. */
INIT_CUMULATIVE_ARGS (args_so_far, funtype, NULL_RTX, (fndecl == 0));
/* If struct_value_rtx is 0, it means pass the address
as if it were an extra parameter. */
if (structure_value_addr && struct_value_rtx == 0)
{
/* If structure_value_addr is a REG other than
virtual_outgoing_args_rtx, we can use always use it. If it
is not a REG, we must always copy it into a register.
If it is virtual_outgoing_args_rtx, we must copy it to another
register in some cases. */
rtx temp = (GET_CODE (structure_value_addr) != REG
|| (ACCUMULATE_OUTGOING_ARGS
&& stack_arg_under_construction
&& structure_value_addr == virtual_outgoing_args_rtx)
? copy_addr_to_reg (structure_value_addr)
: structure_value_addr);
actparms
= tree_cons (error_mark_node,
make_tree (build_pointer_type (TREE_TYPE (funtype)),
temp),
actparms);
structure_value_addr_parm = 1;
}
/* Count the arguments and set NUM_ACTUALS. */
for (p = actparms, i = 0; p; p = TREE_CHAIN (p)) i++;
num_actuals = i;
/* Compute number of named args.
Normally, don't include the last named arg if anonymous args follow.
We do include the last named arg if STRICT_ARGUMENT_NAMING is nonzero.
(If no anonymous args follow, the result of list_length is actually
one too large. This is harmless.)
If PRETEND_OUTGOING_VARARGS_NAMED is set and STRICT_ARGUMENT_NAMING is
zero, this machine will be able to place unnamed args that were
passed in registers into the stack. So treat all args as named.
This allows the insns emitting for a specific argument list to be
independent of the function declaration.
If PRETEND_OUTGOING_VARARGS_NAMED is not set, we do not have any
reliable way to pass unnamed args in registers, so we must force
them into memory. */
if ((STRICT_ARGUMENT_NAMING
|| ! PRETEND_OUTGOING_VARARGS_NAMED)
&& TYPE_ARG_TYPES (funtype) != 0)
n_named_args
= (list_length (TYPE_ARG_TYPES (funtype))
/* Don't include the last named arg. */
- (STRICT_ARGUMENT_NAMING ? 0 : 1)
/* Count the struct value address, if it is passed as a parm. */
+ structure_value_addr_parm);
else
/* If we know nothing, treat all args as named. */
n_named_args = num_actuals;
/* Make a vector to hold all the information about each arg. */
args = (struct arg_data *) alloca (num_actuals
* sizeof (struct arg_data));
bzero ((char *) args, num_actuals * sizeof (struct arg_data));
/* Build up entries inthe ARGS array, compute the size of the arguments
into ARGS_SIZE, etc. */
initialize_argument_information (num_actuals, args, &args_size,
n_named_args, actparms, fndecl,
&args_so_far, reg_parm_stack_space,
&old_stack_level, &old_pending_adj,
&must_preallocate, &flags);
#ifdef FINAL_REG_PARM_STACK_SPACE
reg_parm_stack_space = FINAL_REG_PARM_STACK_SPACE (args_size.constant,
args_size.var);
#endif
if (args_size.var)
{
/* If this function requires a variable-sized argument list, don't
try to make a cse'able block for this call. We may be able to
do this eventually, but it is too complicated to keep track of
what insns go in the cse'able block and which don't.
Also do not make a sibling call. */
flags &= ~(ECF_CONST | ECF_PURE);
must_preallocate = 1;
sibcall_failure = 1;
}
if (args_size.constant > current_function_args_size)
{
/* If this function requires more stack slots than the current
function, we cannot change it into a sibling call. */
sibcall_failure = 1;
}
/* If the callee pops its own arguments, then it must pop exactly
the same number of arguments as the current function. */
if (RETURN_POPS_ARGS (fndecl, funtype, args_size.constant)
!= RETURN_POPS_ARGS (current_function_decl,
TREE_TYPE (current_function_decl),
current_function_args_size))
sibcall_failure = 1;
/* Now make final decision about preallocating stack space. */
must_preallocate = finalize_must_preallocate (must_preallocate,
num_actuals, args,
&args_size);
/* If the structure value address will reference the stack pointer, we
must stabilize it. We don't need to do this if we know that we are
not going to adjust the stack pointer in processing this call. */
if (structure_value_addr
&& (reg_mentioned_p (virtual_stack_dynamic_rtx, structure_value_addr)
|| reg_mentioned_p (virtual_outgoing_args_rtx,
structure_value_addr))
&& (args_size.var
|| (!ACCUMULATE_OUTGOING_ARGS && args_size.constant)))
structure_value_addr = copy_to_reg (structure_value_addr);
/* Precompute any arguments as needed. */
if (pass)
precompute_arguments (flags, num_actuals, args);
@ -2994,14 +3014,13 @@ expand_call (exp, target, ignore)
{
emit_note_after (NOTE_INSN_SETJMP, last);
current_function_calls_setjmp = 1;
sibcall_failure = 1;
}
else
emit_barrier_after (last);
}
if (flags & ECF_LONGJMP)
current_function_calls_longjmp = 1, sibcall_failure = 1;
current_function_calls_longjmp = 1;
/* If this function is returning into a memory location marked as
readonly, it means it is initializing that location. But we normally
@ -3190,6 +3209,14 @@ expand_call (exp, target, ignore)
pending_stack_adjust = save_pending_stack_adjust;
stack_pointer_delta = save_stack_pointer_delta;
/* Prepare arg structure for next iteration. */
for (i = 0 ; i < num_actuals ; i++)
{
args[i].value = 0;
args[i].aligned_regs = 0;
args[i].stack = 0;
}
}
else
normal_call_insns = insns;