From: Jim Wilson <wilson@cygnus.com>
To: linux-ia64@vger.kernel.org
Subject: [Linux-ia64] toolchain patch.011 to eliminate some false DV warnings
Date: Fri, 01 Sep 2000 22:44:39 +0000 [thread overview]
Message-ID: <marc-linux-ia64-105590678205444@msgid-missing> (raw)
This eliminates some false DV warnings that can occur when gcc generates
a predicated call to a function that does not return.
Here is a simple testcase for that. This gets false DV warnings when compiled
with -O2.
#include <stdlib.h>
sub (int i, int k)
{
int j = i ? 1 : 0;
int a;
if (k)
abort ();
a = i ? 3 : 2;
sub2 (a);
return j;
}
2000-09-01 Jim Wilson <wilson@cygnus.com>
* calls.c (emit_call_1): Add REG_NORETURN note to call if ECF_NORETURN.
* combine.c (distribute_notes): Handle REG_NORETURN.
* rtl.c (reg_note_name): Add REG_NORETURN.
* rtl.h (enum reg_note): Likewise.
* config/ia64/ia64-protos.h (emit_safe_across_calls): Renamed from
ia64_file_start.
* config/ia64/ia64.c (emit_safe_across_calls): Likewise.
(rtx_needs_barrier): Handle unspec_volatile 8 and 9.
(emit_predicate_relation_info): Handle conditional calls with
REG_NORETURN.
* config/ia64/ia64.h (ASM_FILE_START): Call emit_safe_across_calls
instead of ia64_file_start.
* config/ia64/sysv4.h (ASM_FILE_START): Likewise.
* config/ia64/ia64.md (safe_across_calls_all,
save_across_calls_normal): New patterns.
Index: calls.c
=================================RCS file: /cvs/cvsfiles/devo/gcc/calls.c,v
retrieving revision 1.190
diff -p -r1.190 calls.c
*** calls.c 2000/07/14 17:44:00 1.190
--- calls.c 2000/09/01 22:26:40
*************** emit_call_1 (funexp, fndecl, funtype, st
*** 586,591 ****
--- 586,595 ----
REG_NOTES (call_insn) = gen_rtx_EXPR_LIST (REG_EH_REGION, const0_rtx,
REG_NOTES (call_insn));
+ if (ecf_flags & ECF_NORETURN)
+ REG_NOTES (call_insn) = gen_rtx_EXPR_LIST (REG_NORETURN, const0_rtx,
+ REG_NOTES (call_insn));
+
SIBLING_CALL_P (call_insn) = ((ecf_flags & ECF_SIBCALL) != 0);
/* Restore this now, so that we do defer pops for this call's args
Index: combine.c
=================================RCS file: /cvs/cvsfiles/devo/gcc/combine.c,v
retrieving revision 1.228.2.1
diff -p -r1.228.2.1 combine.c
*** combine.c 2000/08/19 19:10:32 1.228.2.1
--- combine.c 2000/09/01 22:26:40
*************** distribute_notes (notes, from_insn, i3,
*** 12022,12027 ****
--- 12022,12028 ----
case REG_EH_REGION:
case REG_EH_RETHROW:
+ case REG_NORETURN:
/* These notes must remain with the call. It should not be
possible for both I2 and I3 to be a call. */
if (GET_CODE (i3) = CALL_INSN)
Index: rtl.c
=================================RCS file: /cvs/cvsfiles/devo/gcc/rtl.c,v
retrieving revision 1.77
diff -p -r1.77 rtl.c
*** rtl.c 2000/07/14 17:46:05 1.77
--- rtl.c 2000/09/01 22:26:40
*************** const char * const reg_note_name[] *** 262,268 ****
"REG_LABEL", "REG_DEP_ANTI", "REG_DEP_OUTPUT", "REG_BR_PROB",
"REG_EXEC_COUNT", "REG_NOALIAS", "REG_SAVE_AREA", "REG_BR_PRED",
"REG_FRAME_RELATED_EXPR", "REG_EH_CONTEXT", "REG_EH_REGION",
! "REG_EH_RETHROW", "REG_SAVE_NOTE"
};
static void fatal_with_file_and_line PARAMS ((FILE *, const char *, ...))
--- 262,268 ----
"REG_LABEL", "REG_DEP_ANTI", "REG_DEP_OUTPUT", "REG_BR_PROB",
"REG_EXEC_COUNT", "REG_NOALIAS", "REG_SAVE_AREA", "REG_BR_PRED",
"REG_FRAME_RELATED_EXPR", "REG_EH_CONTEXT", "REG_EH_REGION",
! "REG_EH_RETHROW", "REG_SAVE_NOTE", "REG_NORETURN"
};
static void fatal_with_file_and_line PARAMS ((FILE *, const char *, ...))
Index: rtl.h
=================================RCS file: /cvs/cvsfiles/devo/gcc/rtl.h,v
retrieving revision 1.161.2.1
diff -p -r1.161.2.1 rtl.h
*** rtl.h 2000/07/28 19:57:48 1.161.2.1
--- rtl.h 2000/09/01 22:26:40
*************** enum reg_note
*** 523,529 ****
REG_EH_RETHROW,
/* Used by haifa-sched to save NOTE_INSN notes across scheduling. */
! REG_SAVE_NOTE
};
/* The base value for branch probability notes. */
--- 523,532 ----
REG_EH_RETHROW,
/* Used by haifa-sched to save NOTE_INSN notes across scheduling. */
! REG_SAVE_NOTE,
!
! /* Indicates that a call does not return. */
! REG_NORETURN
};
/* The base value for branch probability notes. */
Index: config/ia64/ia64-protos.h
=================================RCS file: /cvs/cvsfiles/devo/gcc/config/ia64/ia64-protos.h,v
retrieving revision 1.16.2.7
diff -p -r1.16.2.7 ia64-protos.h
*** ia64-protos.h 2000/08/24 21:51:17 1.16.2.7
--- ia64-protos.h 2000/09/01 22:26:41
*************** extern void ia64_encode_section_info PAR
*** 118,124 ****
extern int ia64_register_move_cost PARAMS((enum reg_class, enum reg_class));
extern int ia64_epilogue_uses PARAMS((int));
! extern void ia64_file_start PARAMS((FILE *));
extern void ia64_output_end_prologue PARAMS((FILE *));
extern void ia64_init_builtins PARAMS((void));
extern void ia64_override_options PARAMS((void));
--- 118,124 ----
extern int ia64_register_move_cost PARAMS((enum reg_class, enum reg_class));
extern int ia64_epilogue_uses PARAMS((int));
! extern void emit_safe_across_calls PARAMS((FILE *));
extern void ia64_output_end_prologue PARAMS((FILE *));
extern void ia64_init_builtins PARAMS((void));
extern void ia64_override_options PARAMS((void));
Index: config/ia64/ia64.c
=================================RCS file: /cvs/cvsfiles/devo/gcc/config/ia64/ia64.c,v
retrieving revision 1.71.2.13
diff -p -r1.71.2.13 ia64.c
*** ia64.c 2000/08/25 22:43:38 1.71.2.13
--- ia64.c 2000/09/01 22:26:41[
*************** spill_tfmode_operand (in, force)
*** 984,990 ****
/* Begin the assembly file. */
void
! ia64_file_start (f)
FILE *f;
{
unsigned int rs, re;
--- 984,990 ----
/* Begin the assembly file. */
void
! emit_safe_across_calls (f)
FILE *f;
{
unsigned int rs, re;
*************** rtx_needs_barrier (x, flags, pred)
*** 4003,4008 ****
--- 4003,4010 ----
break;
case 7: /* pred.rel.mutex */
+ case 8: /* safe_across_calls all */
+ case 9: /* safe_across_calls normal */
return 0;
default:
*************** emit_predicate_relation_info (insns)
*** 4248,4253 ****
--- 4250,4284 ----
bb->end = n;
head = n;
}
+ }
+
+ /* Look for conditional calls that do not return, and protect predicate
+ relations around them. Otherwise the assembler will assume the call
+ returns, and complain about uses of call-clobbered predicates after
+ the call. */
+ for (i = n_basic_blocks - 1; i >= 0; --i)
+ {
+ basic_block bb = BASIC_BLOCK (i);
+ rtx insn = bb->head;
+
+ while (1)
+ {
+ if (GET_CODE (insn) = CALL_INSN
+ && GET_CODE (PATTERN (insn)) = COND_EXEC
+ && find_reg_note (insn, REG_NORETURN, NULL_RTX))
+ {
+ rtx b = emit_insn_before (gen_safe_across_calls_all (), insn);
+ rtx a = emit_insn_after (gen_safe_across_calls_normal (), insn);
+ if (bb->head = insn)
+ bb->head = b;
+ if (bb->end = insn)
+ bb->end = a;
+ }
+
+ if (insn = bb->end)
+ break;
+ insn = NEXT_INSN (insn);
+ }
}
}
Index: config/ia64/ia64.h
=================================RCS file: /cvs/cvsfiles/devo/gcc/config/ia64/ia64.h,v
retrieving revision 1.71.2.14
diff -p -r1.71.2.14 ia64.h
*** ia64.h 2000/08/25 22:43:38 1.71.2.14
--- ia64.h 2000/09/01 22:26:41
*************** do { \
*** 1478,1484 ****
/* Output at beginning of assembler file. */
#define ASM_FILE_START(FILE) \
! ia64_file_start (FILE)
/* A C compound statement that outputs the assembler code for a thunk function,
used to implement C++ virtual function calls with multiple inheritance. */
--- 1478,1484 ----
/* Output at beginning of assembler file. */
#define ASM_FILE_START(FILE) \
! emit_safe_across_calls (FILE)
/* A C compound statement that outputs the assembler code for a thunk function,
used to implement C++ virtual function calls with multiple inheritance. */
Index: config/ia64/ia64.md
=================================RCS file: /cvs/cvsfiles/devo/gcc/config/ia64/ia64.md,v
retrieving revision 1.69.2.13
diff -p -r1.69.2.13 ia64.md
*** ia64.md 2000/08/24 21:51:17 1.69.2.13
--- ia64.md 2000/09/01 22:26:41
***************
*** 70,75 ****
--- 70,77 ----
;; 2 insn_group_barrier
;; 5 set_bsp
;; 7 pred.rel.mutex
+ ;; 8 pred.safe_across_calls all
+ ;; 9 pred.safe_across_calls normal
\f
;; ::::::::::::::::::::
;; ::
***************
*** 3944,3946 ****
--- 3946,3967 ----
".pred.rel.mutex %0, %I0"
[(set_attr "type" "unknown")
(set_attr "predicable" "no")])
+
+ (define_insn "safe_across_calls_all"
+ [(unspec_volatile [(const_int 0)] 8)]
+ ""
+ ".pred.safe_across_calls p1-p63"
+ [(set_attr "type" "unknown")
+ (set_attr "predicable" "no")])
+
+ (define_insn "safe_across_calls_normal"
+ [(unspec_volatile [(const_int 0)] 9)]
+ ""
+ "*
+ {
+ emit_safe_across_calls (asm_out_file);
+ return \"\";
+ }"
+ [(set_attr "type" "unknown")
+ (set_attr "predicable" "no")])
+
Index: config/ia64/sysv4.h
=================================RCS file: /cvs/cvsfiles/devo/gcc/config/ia64/sysv4.h,v
retrieving revision 1.14.10.2
diff -p -r1.14.10.2 sysv4.h
*** sysv4.h 2000/08/08 10:02:40 1.14.10.2
--- sysv4.h 2000/09/01 22:26:41
*************** do { \
*** 178,184 ****
#define ASM_FILE_START(STREAM) \
do { \
output_file_directive (STREAM, main_input_filename); \
! ia64_file_start(STREAM); \
} while (0)
/* Case label alignment is handled by ADDR_VEC_ALIGN now. */
--- 178,184 ----
#define ASM_FILE_START(STREAM) \
do { \
output_file_directive (STREAM, main_input_filename); \
! emit_safe_across_calls (STREAM); \
} while (0)
/* Case label alignment is handled by ADDR_VEC_ALIGN now. */
reply other threads:[~2000-09-01 22:44 UTC|newest]
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