Hi!
The following testcase started ICEing with my recent changes to enable
split4 after sel-sched, but it seems the bug is more general.
Some of the i386 splitter condition functions use and rely on df, but
the split passes don't really df_analyze/df_finish_pass, so the DF info
may be stale or not computed at all - the particular ICE is because
there is a new bb and df_get_live_out (bb) returns NULL on it as the
live or lr problem has not been computed yet.
The following patch makes it possible to call df_analyze during split
on demand (on the first occassion where it is needed) and changes the
i386 backend to do so. I needed a target hook that signifies the end
of the split pass so that the backend can reset its flag and return
the todo flags (TODO_df_finish in this case) to the caller if needed.
Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?
2021-02-15 Jakub Jelinek <ja...@redhat.com>
PR target/99104
* target.def: Add split_pass_finish hook.
* doc/tm.texi.in: Add TARGET_SPLIT_PASS_FINISH.
* doc/tm.texi: Regenerated.
* rtl.h (split_all_insns): Change return type from void to
unsigned int.
* recog.c (split_all_insns): Likewise. If targetm.split_pass_finish,
call that hook and return what it returned, otherwise return 0.
(split_all_insns_noflow): If targetm.split_pass_finish,
call that hook and return what it returned.
* config/i386/i386.c (df_analyzed_during_split): New variable.
(ix86_split_pass_finish): New hook.
(ix86_ok_to_clobber_flags): Call df_analyze if it hasn't been
called yet during current split pass. Formatting fix.
(ix86_avoid_lea_for_add): Formatting fix.
(TARGET_SPLIT_PASS_FINISH): Redefine.
* gcc.dg/pr99104.c: New test.
--- gcc/target.def.jj 2021-01-04 10:25:38.997231967 +0100
+++ gcc/target.def 2021-02-15 17:36:51.997016704 +0100
@@ -3209,6 +3209,13 @@ DEFHOOK
bool, (ao_ref *ref),
default_ref_may_alias_errno)
+DEFHOOK
+(split_pass_finish,
+ "Define this to a return TODO flags from the end of a instruction\
+ splitting pass.",
+ unsigned, (void),
+ NULL)
+
/* Support for named address spaces. */
#undef HOOK_PREFIX
#define HOOK_PREFIX "TARGET_ADDR_SPACE_"
--- gcc/doc/tm.texi.in.jj 2021-01-04 10:25:50.624100311 +0100
+++ gcc/doc/tm.texi.in 2021-02-15 17:50:18.887773367 +0100
@@ -3361,6 +3361,8 @@ stack.
@hook TARGET_REF_MAY_ALIAS_ERRNO
+@hook TARGET_SPLIT_PASS_FINISH
+
@hook TARGET_TRANSLATE_MODE_ATTRIBUTE
@hook TARGET_SCALAR_MODE_SUPPORTED_P
--- gcc/doc/tm.texi.jj 2021-01-04 10:25:50.599100594 +0100
+++ gcc/doc/tm.texi 2021-02-15 17:50:45.754465606 +0100
@@ -4303,6 +4303,10 @@ hook returns true for both @code{ptr_mod
Define this to return nonzero if the memory reference @var{ref} may alias
with the system C library errno location. The default version of this hook
assumes the system C library errno location is either a declaration of type
int or accessed by dereferencing a pointer to int.
@end deftypefn
+@deftypefn {Target Hook} unsigned TARGET_SPLIT_PASS_FINISH (void)
+Define this to a return TODO flags from the end of a instruction splitting
pass.
+@end deftypefn
+
@deftypefn {Target Hook} machine_mode TARGET_TRANSLATE_MODE_ATTRIBUTE
(machine_mode @var{mode})
Define this hook if during mode attribute processing, the port should
translate machine_mode @var{mode} to another mode. For example, rs6000's
--- gcc/rtl.h.jj 2021-01-04 10:25:38.778234447 +0100
+++ gcc/rtl.h 2021-02-15 17:52:30.411266758 +0100
@@ -3747,7 +3747,7 @@ extern enum reg_class reg_allocno_class
extern void setup_reg_classes (int, enum reg_class, enum reg_class,
enum reg_class);
-extern void split_all_insns (void);
+extern unsigned int split_all_insns (void);
extern unsigned int split_all_insns_noflow (void);
#define MAX_SAVED_CONST_INT 64
--- gcc/recog.c.jj 2021-02-13 16:08:20.793016638 +0100
+++ gcc/recog.c 2021-02-15 17:38:19.500014240 +0100
@@ -3406,7 +3406,7 @@ split_insn (rtx_insn *insn)
/* Split all insns in the function. If UPD_LIFE, update life info after. */
-void
+unsigned int
split_all_insns (void)
{
bool changed;
@@ -3488,6 +3488,9 @@ split_all_insns (void)
}
checking_verify_flow_info ();
+ if (targetm.split_pass_finish)
+ return targetm.split_pass_finish ();
+ return 0;
}
/* Same as split_all_insns, but do not expect CFG to be available.
@@ -3523,6 +3526,8 @@ split_all_insns_noflow (void)
split_insn (insn);
}
}
+ if (targetm.split_pass_finish)
+ return targetm.split_pass_finish ();
return 0;
}
@@ -4380,8 +4385,7 @@ public:
opt_pass * clone () { return new pass_split_all_insns (m_ctxt); }
virtual unsigned int execute (function *)
{
- split_all_insns ();
- return 0;
+ return split_all_insns ();
}
}; // class pass_split_all_insns
@@ -4425,8 +4429,7 @@ public:
virtual unsigned int execute (function *)
{
- split_all_insns ();
- return 0;
+ return split_all_insns ();
}
}; // class pass_split_after_reload
@@ -4479,8 +4482,7 @@ public:
virtual unsigned int execute (function *)
{
- split_all_insns ();
- return 0;
+ return split_all_insns ();
}
}; // class pass_split_before_sched2
@@ -4519,8 +4521,7 @@ public:
virtual bool gate (function *);
virtual unsigned int execute (function *)
{
- split_all_insns ();
- return 0;
+ return split_all_insns ();
}
}; // class pass_split_before_regstack
--- gcc/config/i386/i386.c.jj 2021-02-15 10:33:17.550216579 +0100
+++ gcc/config/i386/i386.c 2021-02-15 17:49:19.063458659 +0100
@@ -14968,6 +14968,22 @@ ix86_lea_outperforms (rtx_insn *insn, un
return dist_define >= dist_use;
}
+/* True if df_analyze has been called during the current instruction splitting
+ pass. */
+static bool df_analyzed_during_split;
+
+/* Return TODO flags needed at the end of instruction splitting pass. */
+
+static unsigned int
+ix86_split_pass_finish (void)
+{
+ unsigned int todo = 0;
+ gcc_assert (!df_analyzed_during_split || reload_completed);
+ todo = df_analyzed_during_split ? TODO_df_finish : 0;
+ df_analyzed_during_split = false;
+ return todo;
+}
+
/* Return true if it is legal to clobber flags by INSN and
false otherwise. */
@@ -14978,6 +14994,11 @@ ix86_ok_to_clobber_flags (rtx_insn *insn
df_ref use;
bitmap live;
+ if (!df_analyzed_during_split)
+ {
+ df_analyze ();
+ df_analyzed_during_split = true;
+ }
while (insn)
{
if (NONDEBUG_INSN_P (insn))
@@ -14996,7 +15017,7 @@ ix86_ok_to_clobber_flags (rtx_insn *insn
insn = NEXT_INSN (insn);
}
- live = df_get_live_out(bb);
+ live = df_get_live_out (bb);
return !REGNO_REG_SET_P (live, FLAGS_REG);
}
@@ -15013,7 +15034,7 @@ ix86_avoid_lea_for_add (rtx_insn *insn,
return false;
/* Check it is correct to split here. */
- if (!ix86_ok_to_clobber_flags(insn))
+ if (!ix86_ok_to_clobber_flags (insn))
return false;
regno0 = true_regnum (operands[0]);
@@ -23419,6 +23440,9 @@ ix86_run_selftests (void)
#undef TARGET_PROFILE_BEFORE_PROLOGUE
#define TARGET_PROFILE_BEFORE_PROLOGUE ix86_profile_before_prologue
+#undef TARGET_SPLIT_PASS_FINISH
+#define TARGET_SPLIT_PASS_FINISH ix86_split_pass_finish
+
#undef TARGET_MANGLE_DECL_ASSEMBLER_NAME
#define TARGET_MANGLE_DECL_ASSEMBLER_NAME ix86_mangle_decl_assembler_name
--- gcc/testsuite/gcc.dg/pr99104.c.jj 2021-02-15 13:40:13.463563957 +0100
+++ gcc/testsuite/gcc.dg/pr99104.c 2021-02-15 13:39:32.351035762 +0100
@@ -0,0 +1,15 @@
+/* PR target/99104 */
+/* { dg-do compile { target int128 } } */
+/* { dg-options "-O2 -fsel-sched-pipelining -fselective-scheduling2
-funroll-loops" } */
+
+__int128 a;
+int b;
+int foo (void);
+
+int __attribute__ ((simd))
+bar (void)
+{
+ a = ~a;
+ if (foo ())
+ b = 0;
+}
Jakub
