#! /bin/sh -e
# DP: Emit cld instruction when stringops are used (i386).
dir=
if [ $# -eq 3 -a "$2" = '-d' ]; then
pdir="-d $3"
dir="$3/"
elif [ $# -ne 1 ]; then
echo >&2 "`basename $0`: script expects -patch|-unpatch as argument"
exit 1
fi
case "$1" in
-patch)
patch $pdir -f --no-backup-if-mismatch -p0 < $0
;;
-unpatch)
patch $pdir -f --no-backup-if-mismatch -R -p0 < $0
;;
*)
echo >&2 "`basename $0`: script expects -patch|-unpatch as argument"
exit 1
esac
exit 0
2008-03-06 Uros Bizjak <ubizjak@gmail.com>
* config/i386/i386.h (TARGET_CLD): New define.
(struct machine_function): Add needs_cld field.
(ix86_current_function_needs_cld): New define.
* config/i386/i386.md (UNSPEC_CLD): New unspec volatile constant.
("cld"): New isns pattern.
("strmov_singleop"): Set ix86_current_function_needs_cld flag.
("rep_mov"): Ditto.
("strset_singleop"): Ditto.
("rep_stos"): Ditto.
("cmpstrnqi_nz_1"): Ditto.
("cmpstrnqi_1"): Ditto.
("strlenqi_1"): Ditto.
* config/i386/i386.c (ix86_expand_prologue): Emit cld insn for
TARGET_CLD when ix86_current_function_needs_cld is set.
Index: gcc/config/i386/i386.h
===================================================================
--- gcc/config/i386/i386.h (revision 132966)
+++ gcc/config/i386/i386.h (working copy)
@@ -388,6 +388,7 @@ extern unsigned int ix86_arch_features[X
extern int x86_prefetch_sse;
+#define TARGET_CLD 1
#define TARGET_ABM x86_abm
#define TARGET_CMPXCHG16B x86_cmpxchg16b
#define TARGET_POPCNT x86_popcnt
@@ -2446,8 +2447,9 @@ struct machine_function GTY(())
int save_varrargs_registers;
int accesses_prev_frame;
int optimize_mode_switching[MAX_386_ENTITIES];
- /* Set by ix86_compute_frame_layout and used by prologue/epilogue expander to
- determine the style used. */
+ int needs_cld;
+ /* Set by ix86_compute_frame_layout and used by prologue/epilogue
+ expander to determine the style used. */
int use_fast_prologue_epilogue;
/* Number of saved registers USE_FAST_PROLOGUE_EPILOGUE has been computed
for. */
@@ -2467,6 +2469,7 @@ struct machine_function GTY(())
#define ix86_stack_locals (cfun->machine->stack_locals)
#define ix86_save_varrargs_registers (cfun->machine->save_varrargs_registers)
#define ix86_optimize_mode_switching (cfun->machine->optimize_mode_switching)
+#define ix86_current_function_needs_cld (cfun->machine->needs_cld)
#define ix86_tls_descriptor_calls_expanded_in_cfun \
(cfun->machine->tls_descriptor_call_expanded_p)
/* Since tls_descriptor_call_expanded is not cleared, even if all TLS
Index: gcc/config/i386/i386.md
===================================================================
--- gcc/config/i386/i386.md (revision 132966)
+++ gcc/config/i386/i386.md (working copy)
@@ -205,6 +205,7 @@
(UNSPECV_XCHG 12)
(UNSPECV_LOCK 13)
(UNSPECV_PROLOGUE_USE 14)
+ (UNSPECV_CLD 15)
])
;; Constants to represent pcomtrue/pcomfalse variants
@@ -18519,6 +18520,14 @@
;; Block operation instructions
+(define_insn "cld"
+ [(unspec_volatile [(const_int 0)] UNSPECV_CLD)]
+ ""
+ "cld"
+ [(set_attr "length" "1")
+ (set_attr "length_immediate" "0")
+ (set_attr "modrm" "0")])
+
(define_expand "movmemsi"
[(use (match_operand:BLK 0 "memory_operand" ""))
(use (match_operand:BLK 1 "memory_operand" ""))
@@ -18591,7 +18600,7 @@
(set (match_operand 2 "register_operand" "")
(match_operand 5 "" ""))])]
"TARGET_SINGLE_STRINGOP || optimize_size"
- "")
+ "ix86_current_function_needs_cld = 1;")
(define_insn "*strmovdi_rex_1"
[(set (mem:DI (match_operand:DI 2 "register_operand" "0"))
@@ -18708,7 +18717,7 @@
(match_operand 3 "memory_operand" ""))
(use (match_dup 4))])]
""
- "")
+ "ix86_current_function_needs_cld = 1;")
(define_insn "*rep_movdi_rex64"
[(set (match_operand:DI 2 "register_operand" "=c") (const_int 0))
@@ -18868,7 +18877,7 @@
(set (match_operand 0 "register_operand" "")
(match_operand 3 "" ""))])]
"TARGET_SINGLE_STRINGOP || optimize_size"
- "")
+ "ix86_current_function_needs_cld = 1;")
(define_insn "*strsetdi_rex_1"
[(set (mem:DI (match_operand:DI 1 "register_operand" "0"))
@@ -18962,7 +18971,7 @@
(use (match_operand 3 "register_operand" ""))
(use (match_dup 1))])]
""
- "")
+ "ix86_current_function_needs_cld = 1;")
(define_insn "*rep_stosdi_rex64"
[(set (match_operand:DI 1 "register_operand" "=c") (const_int 0))
@@ -19138,7 +19147,7 @@
(clobber (match_operand 1 "register_operand" ""))
(clobber (match_dup 2))])]
""
- "")
+ "ix86_current_function_needs_cld = 1;")
(define_insn "*cmpstrnqi_nz_1"
[(set (reg:CC FLAGS_REG)
@@ -19185,7 +19194,7 @@
(clobber (match_operand 1 "register_operand" ""))
(clobber (match_dup 2))])]
""
- "")
+ "ix86_current_function_needs_cld = 1;")
(define_insn "*cmpstrnqi_1"
[(set (reg:CC FLAGS_REG)
@@ -19254,7 +19263,7 @@
(clobber (match_operand 1 "register_operand" ""))
(clobber (reg:CC FLAGS_REG))])]
""
- "")
+ "ix86_current_function_needs_cld = 1;")
(define_insn "*strlenqi_1"
[(set (match_operand:SI 0 "register_operand" "=&c")
Index: gcc/config/i386/i386.c
===================================================================
--- gcc/config/i386/i386.c (revision 132966)
+++ gcc/config/i386/i386.c (working copy)
@@ -6498,6 +6498,10 @@ ix86_expand_prologue (void)
emit_insn (gen_prologue_use (pic_offset_table_rtx));
emit_insn (gen_blockage ());
}
+
+ /* Emit cld instruction if stringops are used in the function. */
+ if (TARGET_CLD && ix86_current_function_needs_cld)
+ emit_insn (gen_cld ());
}
/* Emit code to restore saved registers using MOV insns. First register