On Thu, 20 Dec 2012, Richard Biener wrote:
> On Thu, 20 Dec 2012, Richard Biener wrote:
>
> > On Thu, 20 Dec 2012, Jakub Jelinek wrote:
> >
> > > On Thu, Dec 20, 2012 at 02:51:55PM +0100, Richard Biener wrote:
> > > > In the PR we perform expression replacement of an FP operation
> > > > across a builtin call that sets the FP control register. This
> > > > patch restricts replacement across calls further, from allowing
> > > > all builtins to only allowing those without side-effects.
> > > >
> > > > Allowing replacement over calls at all was to not pessimize
> > > > FP code generation for example for sqrt which is most often
> > > > expanded to a single instruction.
> > > >
> > > > Bootstrap and regtest running on x86_64-unknown-linux-gnu.
> > > >
> > > > Comments?
> > >
> > > Wouldn't it be better to have there a list of known builtins over which it
> > > is fine to do TER? I'd bet most of memory or string builtins that don't
> > > call malloc/free should be still ok, but they surely have side-effects.
> >
> > I'm not sure - the original reason was that replacing across calls
> > made us spill more because there was a call. We agreed that replacing
> > across calls isn't usually a good idea but put in the (admittedly bad)
> > workaround to still allow doing so across likely-not-calls.
> > string builtins generally will expand to calls though.
> >
> > I was thinking of even making it stronger and increment "cur_call_cnt"
> > when the stmt (even non-call) has side-effects (would for example
> > cover volatile asms or general volatile touching insns).
After discussing on IRC I am testing the following which adds
a target hook and just treats ldmxcsr and stmxcsr differently
as well as all volatile asms and internal functions.
Bootstrap & regtest on x86_64-unknown-linux-gnu running.
Ok for trunk?
Thanks,
Richard.
2012-12-20 Richard Biener <rguent...@suse.de>
PR middle-end/55752
* target.def (sched): Add scheduling_barrier_p.
* targhooks.c (default_scheduling_barrier_p): New function.
* targhooks.h (default_scheduling_barrier_p): Declare.
* doc/tm.texi.in (TARGET_SCHED_SCHEDULING_BARRIER_P): Add.
* doc/tm.texi: Update.
* tree-ssa-ter.c: Include target.h.
(find_replaceable_in_bb): Do not schedule across volatile
asms or stmts the target thinks are scheduling barriers.
Do not treat internal functions as scheduling barrier by default.
* i386/i386.c (TARGET_SCHED_SCHEDULING_BARRIER_P): Override.
(ix86_scheduling_barrier_p): New function. Handle
IX86_BUILTIN_LDMXCSR and IX86_BUILTIN_STMXCSR.
* Makefile.in (tree-ssa-ter.o): Add $(TARGET_H) dependency.
Index: gcc/target.def
===================================================================
*** gcc/target.def (revision 194632)
--- gcc/target.def (working copy)
*************** parallelism required in output calculati
*** 939,944 ****
--- 939,954 ----
int, (unsigned int opc, enum machine_mode mode),
hook_int_uint_mode_1)
+ /* The following member value is a function that returns whether
+ the statement is considered a barrier for scheduling. By default
+ this returns false. */
+ DEFHOOK
+ (scheduling_barrier_p,
+ "This hook is called by TER to determine whether the statement is\n\
+ a scheduling barrier.",
+ bool, (gimple stmt),
+ default_scheduling_barrier_p)
+
HOOK_VECTOR_END (sched)
/* Functions relating to vectorization. */
Index: gcc/targhooks.c
===================================================================
*** gcc/targhooks.c (revision 194632)
--- gcc/targhooks.c (working copy)
*************** default_canonicalize_comparison (int *,
*** 1547,1550 ****
--- 1547,1557 ----
{
}
+ /* Default version of scheduling_barrier_p. */
+ bool
+ default_scheduling_barrier_p (gimple)
+ {
+ return false;
+ }
+
#include "gt-targhooks.h"
Index: gcc/targhooks.h
===================================================================
*** gcc/targhooks.h (revision 194632)
--- gcc/targhooks.h (working copy)
*************** extern const char *default_pch_valid_p (
*** 195,197 ****
--- 195,199 ----
extern void default_asm_output_ident_directive (const char*);
extern bool default_member_type_forces_blk (const_tree, enum machine_mode);
+
+ extern bool default_scheduling_barrier_p (gimple);
Index: gcc/doc/tm.texi.in
===================================================================
*** gcc/doc/tm.texi.in (revision 194632)
--- gcc/doc/tm.texi.in (working copy)
*************** in its second parameter.
*** 6737,6742 ****
--- 6737,6744 ----
@hook TARGET_SCHED_REASSOCIATION_WIDTH
+ @hook TARGET_SCHED_SCHEDULING_BARRIER_P
+
@node Sections
@section Dividing the Output into Sections (Texts, Data, @dots{})
@c the above section title is WAY too long. maybe cut the part between
Index: gcc/doc/tm.texi
===================================================================
*** gcc/doc/tm.texi (revision 194632)
--- gcc/doc/tm.texi (working copy)
*************** This hook is called by tree reassociator
*** 6840,6845 ****
--- 6840,6850 ----
parallelism required in output calculations chain.
@end deftypefn
+ @deftypefn {Target Hook} bool TARGET_SCHED_SCHEDULING_BARRIER_P (gimple
@var{stmt})
+ This hook is called by TER to determine whether the statement is
+ a scheduling barrier.
+ @end deftypefn
+
@node Sections
@section Dividing the Output into Sections (Texts, Data, @dots{})
@c the above section title is WAY too long. maybe cut the part between
Index: gcc/tree-ssa-ter.c
===================================================================
*** gcc/tree-ssa-ter.c (revision 194632)
--- gcc/tree-ssa-ter.c (working copy)
*************** along with GCC; see the file COPYING3.
*** 31,36 ****
--- 31,37 ----
#include "dumpfile.h"
#include "tree-ssa-live.h"
#include "flags.h"
+ #include "target.h"
/* Temporary Expression Replacement (TER)
*************** find_replaceable_in_bb (temp_expr_table_
*** 681,692 ****
kill_expr (tab, partition);
}
! /* Increment counter if this is a non BUILT_IN call. We allow
! replacement over BUILT_IN calls since many will expand to inline
! insns instead of a true call. */
! if (is_gimple_call (stmt)
! && !((fndecl = gimple_call_fndecl (stmt))
! && DECL_BUILT_IN (fndecl)))
cur_call_cnt++;
/* Now see if we are creating a new expression or not. */
--- 682,697 ----
kill_expr (tab, partition);
}
! /* Increment counter if this is not a BUILT_IN call or a stmt with
! side-effects. We allow replacement over BUILT_IN calls
! since many will expand to inline insns instead of a true call. */
! if ((gimple_code (stmt) == GIMPLE_ASM
! && gimple_asm_volatile_p (stmt))
! || (is_gimple_call (stmt)
! && !gimple_call_internal_p (stmt)
! && !((fndecl = gimple_call_fndecl (stmt))
! && DECL_BUILT_IN (fndecl)))
! || targetm.sched.scheduling_barrier_p (stmt))
cur_call_cnt++;
/* Now see if we are creating a new expression or not. */
Index: gcc/config/i386/i386.c
===================================================================
*** gcc/config/i386/i386.c (revision 194632)
--- gcc/config/i386/i386.c (working copy)
*************** ix86_enum_va_list (int idx, const char *
*** 41159,41164 ****
--- 41159,41166 ----
#define TARGET_SCHED_ADJUST_PRIORITY ix86_adjust_priority
#undef TARGET_SCHED_DEPENDENCIES_EVALUATION_HOOK
#define TARGET_SCHED_DEPENDENCIES_EVALUATION_HOOK
ix86_dependencies_evaluation_hook
+ #undef TARGET_SCHED_SCHEDULING_BARRIER_P
+ #define TARGET_SCHED_SCHEDULING_BARRIER_P ix86_scheduling_barrier_p
/* The size of the dispatch window is the total number of bytes of
object code allowed in a window. */
*************** ix86_reassociation_width (unsigned int o
*** 41982,41987 ****
--- 41984,42014 ----
return res;
}
+ /* Implementation of scheduling_barrier_p. */
+
+ static bool
+ ix86_scheduling_barrier_p (gimple stmt)
+ {
+ if (!is_gimple_call (stmt))
+ return false;
+
+ tree fndecl = gimple_call_fndecl (stmt);
+ if (!fndecl
+ || DECL_BUILT_IN_CLASS (fndecl) != BUILT_IN_MD)
+ return false;
+
+ switch (DECL_FUNCTION_CODE (fndecl))
+ {
+ case IX86_BUILTIN_LDMXCSR:
+ case IX86_BUILTIN_STMXCSR:
+ return true;
+
+ default:;
+ }
+
+ return false;
+ }
+
/* ??? No autovectorization into MMX or 3DNOW until we can reliably
place emms and femms instructions. */
Index: gcc/Makefile.in
===================================================================
*** gcc/Makefile.in (revision 194632)
--- gcc/Makefile.in (working copy)
*************** tree-into-ssa.o : tree-into-ssa.c $(TREE
*** 2272,2278 ****
tree-ssa-ter.o : tree-ssa-ter.c $(TREE_FLOW_H) $(CONFIG_H) $(SYSTEM_H) \
$(TREE_H) $(DIAGNOSTIC_H) $(TM_H) coretypes.h dumpfile.h \
$(TREE_SSA_LIVE_H) $(BITMAP_H) $(FLAGS_H) \
! $(GIMPLE_PRETTY_PRINT_H)
tree-ssa-coalesce.o : tree-ssa-coalesce.c $(TREE_FLOW_H) $(CONFIG_H) \
$(SYSTEM_H) $(TREE_H) $(DIAGNOSTIC_H) $(TM_H) coretypes.h dumpfile.h \
$(TREE_SSA_LIVE_H) $(BITMAP_H) $(FLAGS_H) $(HASH_TABLE_H) \
--- 2272,2278 ----
tree-ssa-ter.o : tree-ssa-ter.c $(TREE_FLOW_H) $(CONFIG_H) $(SYSTEM_H) \
$(TREE_H) $(DIAGNOSTIC_H) $(TM_H) coretypes.h dumpfile.h \
$(TREE_SSA_LIVE_H) $(BITMAP_H) $(FLAGS_H) \
! $(GIMPLE_PRETTY_PRINT_H) $(TARGET_H)
tree-ssa-coalesce.o : tree-ssa-coalesce.c $(TREE_FLOW_H) $(CONFIG_H) \
$(SYSTEM_H) $(TREE_H) $(DIAGNOSTIC_H) $(TM_H) coretypes.h dumpfile.h \
$(TREE_SSA_LIVE_H) $(BITMAP_H) $(FLAGS_H) $(HASH_TABLE_H) \
