mirror/gcc
1
0
Fork 0
mirror of https://github.com/gcc-mirror/gcc.git synced 2024-11-21 13:40:47 +00:00
Code Issues Actions Packages Projects Releases Wiki Activity

ipa-modref bits for unsequenced and reproducible

Browse Source 
C attributes reproducible and unsequenced implies that calling function twice
leads to same effect if parameters are otherwise unchanged (function call
itself does not count).  This is bit bit stronger that modref's notion of
nondeterminism that says that same inputs will yield same outputs (function
call itself does count).

This patch makes reproducible/unsequenced imply determinism and cleans up
determinism handling.  By itself it is not useful, since we can not make use of it
unless we know what are the inputs/outputs of the function which I plan to handle
by the "fn spec" attribute.

gcc/ChangeLog:

	* ipa-modref.cc (modref_summary::useful_p): const/pure implies
	determinism.
	(modref_summary_lto::useful_p): Likewise.
	(ignore_nondeterminism_p): Add CALLEE_FNTYPE parameter; check for
	reproducible/unsequenced
	(modref_access_analysis::record_access_p): Use ignore_nondeterminism_p
	when handling volatile accesses.
	(modref_access_analysis::get_access_for_fnspec): Update.
	(modref_access_analysis::process_fnspec): Cleanup handling of NOVOPS.
	(modref_access_analysis::analyze_call): Use ignore_nondeterminism_p
	when handling asm statements.
	(modref_access_analysis::analyze_stmt): Update.
	(propagate_unknown_call): Update.
	(modref_propagate_in_scc): Update.
	(ipa_merge_modref_summary_after_inlining): Update.
This commit is contained in:
Jan Hubicka 2024-11-17 11:54:10 +01:00
parent aac5c57ee1
commit addf022820
1 changed files with 53 additions and 37 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

76
gcc/ipa-modref.cc
View File

@ -336,15 +336,13 @@ modref_summary::useful_p (int ecf_flags, bool check_flags)
&& remove_useless_eaf_flags (static_chain_flags, ecf_flags, false))
return true;
if (ecf_flags & ECF_CONST)
return ((!side_effects || !nondeterministic)
&& (ecf_flags & ECF_LOOPING_CONST_OR_PURE));
return (!side_effects && (ecf_flags & ECF_LOOPING_CONST_OR_PURE));
if (loads && !loads->every_base)
return true;
else
kills.release ();
if (ecf_flags & ECF_PURE)
return ((!side_effects || !nondeterministic)
&& (ecf_flags & ECF_LOOPING_CONST_OR_PURE));
return (!side_effects && (ecf_flags & ECF_LOOPING_CONST_OR_PURE));
return stores && !stores->every_base;
}
@ -409,15 +407,13 @@ modref_summary_lto::useful_p (int ecf_flags, bool check_flags)
&& remove_useless_eaf_flags (static_chain_flags, ecf_flags, false))
return true;
if (ecf_flags & (ECF_CONST | ECF_NOVOPS))
return ((!side_effects || !nondeterministic)
&& (ecf_flags & ECF_LOOPING_CONST_OR_PURE));
return (!side_effects && (ecf_flags & ECF_LOOPING_CONST_OR_PURE));
if (loads && !loads->every_base)
return true;
else
kills.release ();
if (ecf_flags & ECF_PURE)
return ((!side_effects || !nondeterministic)
&& (ecf_flags & ECF_LOOPING_CONST_OR_PURE));
return (!side_effects && (ecf_flags & ECF_LOOPING_CONST_OR_PURE));
return stores && !stores->every_base;
}
@ -794,13 +790,25 @@ namespace {
/* Return true if ECF flags says that nondeterminism can be ignored. */
static bool
ignore_nondeterminism_p (tree caller, int flags)
ignore_nondeterminism_p (tree caller, int flags, tree callee_fntype)
{
if (flags & (ECF_CONST | ECF_PURE))
int caller_flags = flags_from_decl_or_type (caller);
if ((flags | caller_flags) & (ECF_CONST | ECF_PURE))
return true;
if ((flags & (ECF_NORETURN | ECF_NOTHROW)) == (ECF_NORETURN | ECF_NOTHROW)
|| (!opt_for_fn (caller, flag_exceptions) && (flags & ECF_NORETURN)))
return true;
/* C language defines unsequenced and reproducible functions
to be deterministic. */
if (lookup_attribute ("unsequenced", TYPE_ATTRIBUTES (TREE_TYPE (caller)))
|| lookup_attribute ("reproducible",
TYPE_ATTRIBUTES (TREE_TYPE (caller))))
return true;
if (callee_fntype
&& (lookup_attribute ("unsequenced", TYPE_ATTRIBUTES (callee_fntype))
|| lookup_attribute ("reproducible",
TYPE_ATTRIBUTES (callee_fntype))))
return true;
return false;
}
@ -1151,7 +1159,8 @@ modref_access_analysis::record_access_lto (modref_records_lto *tt, ao_ref *ref,
bool
modref_access_analysis::record_access_p (tree expr)
{
if (TREE_THIS_VOLATILE (expr))
if (TREE_THIS_VOLATILE (expr)
&& !ignore_nondeterminism_p (current_function_decl, 0, NULL))
{
if (dump_file)
fprintf (dump_file, " (volatile; marking nondeterministic) ");
@ -1288,7 +1297,8 @@ modref_access_analysis::merge_call_side_effects
changed = true;
}
if (!m_summary->nondeterministic && callee_summary->nondeterministic
&& !ignore_nondeterminism_p (current_function_decl, flags))
&& !ignore_nondeterminism_p (current_function_decl, flags,
gimple_call_fntype (call)))
{
if (dump_file)
fprintf (dump_file, " - merging nondeterministic.\n");
@ -1455,6 +1465,7 @@ modref_access_analysis::get_access_for_fnspec (gcall *call, attr_fnspec &fnspec,
}
return a;
}
/* Apply side effects of call STMT to CUR_SUMMARY using FNSPEC.
If IGNORE_STORES is true ignore them.
Return false if no useful summary can be produced. */
@ -1472,7 +1483,8 @@ modref_access_analysis::process_fnspec (gcall *call)
&& stmt_could_throw_p (cfun, call)))
{
set_side_effects ();
if (!ignore_nondeterminism_p (current_function_decl, flags))
if (!ignore_nondeterminism_p (current_function_decl, flags,
gimple_call_fntype (call)))
set_nondeterministic ();
}
@ -1625,12 +1637,6 @@ modref_access_analysis::analyze_call (gcall *stmt)
if (dump_file)
fprintf (dump_file, gimple_call_internal_p (stmt)
? " - Internal call" : " - Indirect call.\n");
if (flags & ECF_NOVOPS)
{
set_side_effects ();
set_nondeterministic ();
}
else
process_fnspec (stmt);
return;
}
@ -1800,7 +1806,8 @@ modref_access_analysis::analyze_stmt (gimple *stmt, bool always_executed)
switch (gimple_code (stmt))
{
case GIMPLE_ASM:
if (gimple_asm_volatile_p (as_a <gasm *> (stmt)))
if (gimple_asm_volatile_p (as_a <gasm *> (stmt))
&& !ignore_nondeterminism_p (current_function_decl, 0, NULL))
set_nondeterministic ();
if (cfun->can_throw_non_call_exceptions
&& stmt_could_throw_p (cfun, stmt))
@ -4592,19 +4599,22 @@ propagate_unknown_call (cgraph_node *node,
cur_summary_lto->side_effects = true;
changed = true;
}
if (cur_summary && !cur_summary->nondeterministic
&& !ignore_nondeterminism_p (node->decl, ecf_flags))
if (!ignore_nondeterminism_p (node->decl, ecf_flags,
e->callee ? TREE_TYPE (e->callee->decl)
: NULL_TREE))
{
if (cur_summary && !cur_summary->nondeterministic)
{
cur_summary->nondeterministic = true;
changed = true;
}
if (cur_summary_lto && !cur_summary_lto->nondeterministic
&& !ignore_nondeterminism_p (node->decl, ecf_flags))
if (cur_summary_lto && !cur_summary_lto->nondeterministic)
{
cur_summary_lto->nondeterministic = true;
changed = true;
}
}
}
if (ecf_flags & (ECF_CONST | ECF_NOVOPS))
return changed;
@ -4869,14 +4879,18 @@ modref_propagate_in_scc (cgraph_node *component_node)
}
if (callee_summary && !cur_summary->nondeterministic
&& callee_summary->nondeterministic
&& !ignore_nondeterminism_p (cur->decl, flags))
&& !ignore_nondeterminism_p
(cur->decl, flags,
TREE_TYPE (callee_edge->callee->decl)))
{
cur_summary->nondeterministic = true;
changed = true;
}
if (callee_summary_lto && !cur_summary_lto->nondeterministic
&& callee_summary_lto->nondeterministic
&& !ignore_nondeterminism_p (cur->decl, flags))
&& !ignore_nondeterminism_p
(cur->decl, flags,
TREE_TYPE (callee_edge->callee->decl)))
{
cur_summary_lto->nondeterministic = true;
changed = true;
@ -5358,20 +5372,22 @@ ipa_merge_modref_summary_after_inlining (cgraph_edge *edge)
if (!(flags & (ECF_CONST | ECF_PURE))
|| (flags & ECF_LOOPING_CONST_OR_PURE))
{
bool set_nondeterministic
= !ignore_nondeterminism_p
(edge->caller->decl, flags,
TREE_TYPE (edge->callee->decl));
if (to_info)
{
if (!callee_info || callee_info->side_effects)
to_info->side_effects = true;
if ((!callee_info || callee_info->nondeterministic)
&& !ignore_nondeterminism_p (edge->caller->decl, flags))
if (set_nondeterministic)
to_info->nondeterministic = true;
}
if (to_info_lto)
{
if (!callee_info_lto || callee_info_lto->side_effects)
to_info_lto->side_effects = true;
if ((!callee_info_lto || callee_info_lto->nondeterministic)
&& !ignore_nondeterminism_p (edge->caller->decl, flags))
if (set_nondeterministic)
to_info_lto->nondeterministic = true;
}
}