[ARM] Turning off 64bits ops in Neon and gfortran/modulo-scheduling problem
Christophe Lyon
christophe.lyon@linaro.org
Wed Dec 19 16:00:00 GMT 2012
On 17 December 2012 16:12, Richard Earnshaw <rearnsha@arm.com> wrote:
> On 29/11/12 17:16, Christophe Lyon wrote:
>> On trunk I have noticed a regression in gfortran when using modulo
>> scheduling: sms-1.f90 now fails, but I suspect it's not because of
>> this patch since forcing compilation for armv5t makes the same test
>> fail with and without my patch.
>>
>
> Hmm, that's worrying. Could you please makesure this is recorded in
> bugzilla. If this is a regression, please mark it as such.
>
I was about to do so, but after bisecting it turns out that the
problem was introduced by
http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=192969 and is very
likely to be another instance of PR55562, which has just been fixed
by http://gcc.gnu.org/ml/gcc-patches/2012-12/msg01137.html.
>
> Now that this optimization is disabled by default, the onlya8 code is
> completely redundant and should be purged, along with the insn alternatives
> that used it.
>
> R.
>
Here is a new version of my patch, with the cleanup you requested.
2012-12-18 Christophe Lyon <christophe.lyon@linaro.org>
gcc/
* config/arm/arm-protos.h (tune_params): Add
prefer_neon_for_64bits field.
* config/arm/arm.c (prefer_neon_for_64bits): New variable.
(arm_slowmul_tune): Default prefer_neon_for_64bits to false.
(arm_fastmul_tune, arm_strongarm_tune, arm_xscale_tune): Ditto.
(arm_9e_tune, arm_v6t2_tune, arm_cortex_tune): Ditto.
(arm_cortex_a5_tune, arm_cortex_a15_tune): Ditto.
(arm_cortex_a9_tune, arm_fa726te_tune): Ditto.
(arm_option_override): Handle -mneon-for-64bits new option.
* config/arm/arm.h (TARGET_PREFER_NEON_64BITS): New macro.
(prefer_neon_for_64bits): Declare new variable.
* config/arm/arm.md (arch): Rename neon_onlya8 and neon_nota8 to
avoid_neon_for_64bits and neon_for_64bits. Remove onlya8 and
nota8.
(arch_enabled): Handle new arch types. Remove support for onlya8
and nota8.
(one_cmpldi2): Use new arch names.
* config/arm/arm.opt (mneon-for-64bits): Add option.
* config/arm/neon.md (adddi3_neon, subdi3_neon, iordi3_neon)
(anddi3_neon, xordi3_neon, ashldi3_neon, <shift>di3_neon): Use
neon_for_64bits instead of nota8 and avoid_neon_for_64bits instead
of onlya8.
* doc/invoke.texi (-mneon-for-64bits): Document.
gcc/testsuite/
* gcc.target/arm/neon-for-64bits-1.c: New tests.
* gcc.target/arm/neon-for-64bits-2.c: Likewise.
-------------- next part --------------
diff --git a/gcc/config/arm/arm-protos.h b/gcc/config/arm/arm-protos.h
index d942c5b..c92f055 100644
--- a/gcc/config/arm/arm-protos.h
+++ b/gcc/config/arm/arm-protos.h
@@ -247,6 +247,8 @@ struct tune_params
performance. The first element covers Thumb state and the second one
is for ARM state. */
bool logical_op_non_short_circuit[2];
+ /* Prefer Neon for 64-bit bitops. */
+ bool prefer_neon_for_64bits;
};
extern const struct tune_params *current_tune;
diff --git a/gcc/config/arm/arm.c b/gcc/config/arm/arm.c
index 84ce56f..5e99436 100644
--- a/gcc/config/arm/arm.c
+++ b/gcc/config/arm/arm.c
@@ -816,6 +816,10 @@ int arm_arch_thumb2;
int arm_arch_arm_hwdiv;
int arm_arch_thumb_hwdiv;
+/* Nonzero if we should use Neon to handle 64-bits operations rather
+ than core registers. */
+int prefer_neon_for_64bits = 0;
+
/* In case of a PRE_INC, POST_INC, PRE_DEC, POST_DEC memory reference,
we must report the mode of the memory reference from
TARGET_PRINT_OPERAND to TARGET_PRINT_OPERAND_ADDRESS. */
@@ -895,6 +899,7 @@ const struct tune_params arm_slowmul_tune =
arm_default_branch_cost,
false, /* Prefer LDRD/STRD. */
{true, true}, /* Prefer non short circuit. */
+ false /* Prefer Neon for 64-bits bitops. */
};
const struct tune_params arm_fastmul_tune =
@@ -908,6 +913,7 @@ const struct tune_params arm_fastmul_tune =
arm_default_branch_cost,
false, /* Prefer LDRD/STRD. */
{true, true}, /* Prefer non short circuit. */
+ false /* Prefer Neon for 64-bits bitops. */
};
/* StrongARM has early execution of branches, so a sequence that is worth
@@ -924,6 +930,7 @@ const struct tune_params arm_strongarm_tune =
arm_default_branch_cost,
false, /* Prefer LDRD/STRD. */
{true, true}, /* Prefer non short circuit. */
+ false /* Prefer Neon for 64-bits bitops. */
};
const struct tune_params arm_xscale_tune =
@@ -937,6 +944,7 @@ const struct tune_params arm_xscale_tune =
arm_default_branch_cost,
false, /* Prefer LDRD/STRD. */
{true, true}, /* Prefer non short circuit. */
+ false /* Prefer Neon for 64-bits bitops. */
};
const struct tune_params arm_9e_tune =
@@ -950,6 +958,7 @@ const struct tune_params arm_9e_tune =
arm_default_branch_cost,
false, /* Prefer LDRD/STRD. */
{true, true}, /* Prefer non short circuit. */
+ false /* Prefer Neon for 64-bits bitops. */
};
const struct tune_params arm_v6t2_tune =
@@ -963,6 +972,7 @@ const struct tune_params arm_v6t2_tune =
arm_default_branch_cost,
false, /* Prefer LDRD/STRD. */
{true, true}, /* Prefer non short circuit. */
+ false /* Prefer Neon for 64-bits bitops. */
};
/* Generic Cortex tuning. Use more specific tunings if appropriate. */
@@ -977,6 +987,7 @@ const struct tune_params arm_cortex_tune =
arm_default_branch_cost,
false, /* Prefer LDRD/STRD. */
{true, true}, /* Prefer non short circuit. */
+ false /* Prefer Neon for 64-bits bitops. */
};
const struct tune_params arm_cortex_a15_tune =
@@ -990,6 +1001,7 @@ const struct tune_params arm_cortex_a15_tune =
arm_default_branch_cost,
true, /* Prefer LDRD/STRD. */
{true, true}, /* Prefer non short circuit. */
+ false /* Prefer Neon for 64-bits bitops. */
};
/* Branches can be dual-issued on Cortex-A5, so conditional execution is
@@ -1006,6 +1018,7 @@ const struct tune_params arm_cortex_a5_tune =
arm_cortex_a5_branch_cost,
false, /* Prefer LDRD/STRD. */
{false, false}, /* Prefer non short circuit. */
+ false /* Prefer Neon for 64-bits bitops. */
};
const struct tune_params arm_cortex_a9_tune =
@@ -1019,6 +1032,7 @@ const struct tune_params arm_cortex_a9_tune =
arm_default_branch_cost,
false, /* Prefer LDRD/STRD. */
{true, true}, /* Prefer non short circuit. */
+ false /* Prefer Neon for 64-bits bitops. */
};
/* The arm_v6m_tune is duplicated from arm_cortex_tune, rather than
@@ -1034,6 +1048,7 @@ const struct tune_params arm_v6m_tune =
arm_default_branch_cost,
false, /* Prefer LDRD/STRD. */
{false, false}, /* Prefer non short circuit. */
+ false /* Prefer Neon for 64-bits bitops. */
};
const struct tune_params arm_fa726te_tune =
@@ -1047,6 +1062,7 @@ const struct tune_params arm_fa726te_tune =
arm_default_branch_cost,
false, /* Prefer LDRD/STRD. */
{true, true}, /* Prefer non short circuit. */
+ false /* Prefer Neon for 64-bits bitops. */
};
@@ -2077,6 +2093,12 @@ arm_option_override (void)
global_options.x_param_values,
global_options_set.x_param_values);
+ /* Use Neon to perform 64-bits operations rather than core
+ registers. */
+ prefer_neon_for_64bits = current_tune->prefer_neon_for_64bits;
+ if (use_neon_for_64bits == 1)
+ prefer_neon_for_64bits = true;
+
/* Use the alternative scheduling-pressure algorithm by default. */
maybe_set_param_value (PARAM_SCHED_PRESSURE_ALGORITHM, 2,
global_options.x_param_values,
diff --git a/gcc/config/arm/arm.h b/gcc/config/arm/arm.h
index d0f351d..bcaa890 100644
--- a/gcc/config/arm/arm.h
+++ b/gcc/config/arm/arm.h
@@ -356,6 +356,9 @@ extern void (*arm_lang_output_object_attributes_hook)(void);
#define TARGET_IDIV ((TARGET_ARM && arm_arch_arm_hwdiv) \
|| (TARGET_THUMB2 && arm_arch_thumb_hwdiv))
+/* Should NEON be used for 64-bits bitops. */
+#define TARGET_PREFER_NEON_64BITS (prefer_neon_for_64bits)
+
/* True iff the full BPABI is being used. If TARGET_BPABI is true,
then TARGET_AAPCS_BASED must be true -- but the converse does not
hold. TARGET_BPABI implies the use of the BPABI runtime library,
@@ -541,6 +544,10 @@ extern int arm_arch_arm_hwdiv;
/* Nonzero if chip supports integer division instruction in Thumb mode. */
extern int arm_arch_thumb_hwdiv;
+/* Nonzero if we should use Neon to handle 64-bits operations rather
+ than core registers. */
+extern int prefer_neon_for_64bits;
+
#ifndef TARGET_DEFAULT
#define TARGET_DEFAULT (MASK_APCS_FRAME)
#endif
diff --git a/gcc/config/arm/arm.md b/gcc/config/arm/arm.md
index 649e901..e24c2b4 100644
--- a/gcc/config/arm/arm.md
+++ b/gcc/config/arm/arm.md
@@ -96,7 +96,7 @@
; for ARM or Thumb-2 with arm_arch6, and nov6 for ARM without
; arm_arch6. This attribute is used to compute attribute "enabled",
; use type "any" to enable an alternative in all cases.
-(define_attr "arch" "any,a,t,32,t1,t2,v6,nov6,onlya8,neon_onlya8,nota8,neon_nota8,iwmmxt,iwmmxt2"
+(define_attr "arch" "any,a,t,32,t1,t2,v6,nov6,neon_for_64bits,avoid_neon_for_64bits,iwmmxt,iwmmxt2"
(const_string "any"))
(define_attr "arch_enabled" "no,yes"
@@ -131,22 +131,14 @@
(match_test "TARGET_32BIT && !arm_arch6"))
(const_string "yes")
- (and (eq_attr "arch" "onlya8")
- (eq_attr "tune" "cortexa8"))
+ (and (eq_attr "arch" "avoid_neon_for_64bits")
+ (match_test "TARGET_NEON")
+ (not (match_test "TARGET_PREFER_NEON_64BITS")))
(const_string "yes")
- (and (eq_attr "arch" "neon_onlya8")
- (eq_attr "tune" "cortexa8")
- (match_test "TARGET_NEON"))
- (const_string "yes")
-
- (and (eq_attr "arch" "nota8")
- (not (eq_attr "tune" "cortexa8")))
- (const_string "yes")
-
- (and (eq_attr "arch" "neon_nota8")
- (not (eq_attr "tune" "cortexa8"))
- (match_test "TARGET_NEON"))
+ (and (eq_attr "arch" "neon_for_64bits")
+ (match_test "TARGET_NEON")
+ (match_test "TARGET_PREFER_NEON_64BITS"))
(const_string "yes")
(and (eq_attr "arch" "iwmmxt2")
@@ -4326,7 +4318,7 @@
[(set_attr "length" "*,8,8,*")
(set_attr "predicable" "no,yes,yes,no")
(set_attr "neon_type" "neon_int_1,*,*,neon_int_1")
- (set_attr "arch" "neon_nota8,*,*,neon_onlya8")]
+ (set_attr "arch" "neon_for_64bits,*,*,avoid_neon_for_64bits")]
)
(define_expand "one_cmplsi2"
diff --git a/gcc/config/arm/arm.opt b/gcc/config/arm/arm.opt
index 61d2d2f..c4ede22 100644
--- a/gcc/config/arm/arm.opt
+++ b/gcc/config/arm/arm.opt
@@ -247,3 +247,7 @@ that may trigger Cortex-M3 errata.
munaligned-access
Target Report Var(unaligned_access) Init(2)
Enable unaligned word and halfword accesses to packed data.
+
+mneon-for-64bits
+Target Report RejectNegative Var(use_neon_for_64bits) Init(0)
+Use Neon to perform 64-bits operations rather than core registers.
diff --git a/gcc/config/arm/neon.md b/gcc/config/arm/neon.md
index fc38269..6e13d1a 100644
--- a/gcc/config/arm/neon.md
+++ b/gcc/config/arm/neon.md
@@ -488,7 +488,7 @@
[(set_attr "neon_type" "neon_int_1,*,*,neon_int_1,*,*,*")
(set_attr "conds" "*,clob,clob,*,clob,clob,clob")
(set_attr "length" "*,8,8,*,8,8,8")
- (set_attr "arch" "nota8,*,*,onlya8,*,*,*")]
+ (set_attr "arch" "neon_for_64bits,*,*,avoid_neon_for_64bits,*,*,*")]
)
(define_insn "*sub<mode>3_neon"
@@ -525,7 +525,7 @@
[(set_attr "neon_type" "neon_int_2,*,*,*,neon_int_2")
(set_attr "conds" "*,clob,clob,clob,*")
(set_attr "length" "*,8,8,8,*")
- (set_attr "arch" "nota8,*,*,*,onlya8")]
+ (set_attr "arch" "neon_for_64bits,*,*,*,avoid_neon_for_64bits")]
)
(define_insn "*mul<mode>3_neon"
@@ -700,7 +700,7 @@
}
[(set_attr "neon_type" "neon_int_1,neon_int_1,*,*,neon_int_1,neon_int_1")
(set_attr "length" "*,*,8,8,*,*")
- (set_attr "arch" "nota8,nota8,*,*,onlya8,onlya8")]
+ (set_attr "arch" "neon_for_64bits,neon_for_64bits,*,*,avoid_neon_for_64bits,avoid_neon_for_64bits")]
)
;; The concrete forms of the Neon immediate-logic instructions are vbic and
@@ -745,7 +745,7 @@
}
[(set_attr "neon_type" "neon_int_1,neon_int_1,*,*,neon_int_1,neon_int_1")
(set_attr "length" "*,*,8,8,*,*")
- (set_attr "arch" "nota8,nota8,*,*,onlya8,onlya8")]
+ (set_attr "arch" "neon_for_64bits,neon_for_64bits,*,*,avoid_neon_for_64bits,avoid_neon_for_64bits")]
)
(define_insn "orn<mode>3_neon"
@@ -841,7 +841,7 @@
veor\t%P0, %P1, %P2"
[(set_attr "neon_type" "neon_int_1,*,*,neon_int_1")
(set_attr "length" "*,8,8,*")
- (set_attr "arch" "nota8,*,*,onlya8")]
+ (set_attr "arch" "neon_for_64bits,*,*,avoid_neon_for_64bits")]
)
(define_insn "one_cmpl<mode>2"
@@ -1163,7 +1163,7 @@
}
DONE;
}"
- [(set_attr "arch" "nota8,nota8,*,*,onlya8,onlya8")
+ [(set_attr "arch" "neon_for_64bits,neon_for_64bits,*,*,avoid_neon_for_64bits,avoid_neon_for_64bits")
(set_attr "opt" "*,*,speed,speed,*,*")]
)
@@ -1264,7 +1264,7 @@
DONE;
}"
- [(set_attr "arch" "nota8,nota8,*,*,onlya8,onlya8")
+ [(set_attr "arch" "neon_for_64bits,neon_for_64bits,*,*,avoid_neon_for_64bits,avoid_neon_for_64bits")
(set_attr "opt" "*,*,speed,speed,*,*")]
)
diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi
index 06ba770..01faecd 100644
--- a/gcc/doc/invoke.texi
+++ b/gcc/doc/invoke.texi
@@ -513,7 +513,8 @@ Objective-C and Objective-C++ Dialects}.
-mtp=@var{name} -mtls-dialect=@var{dialect} @gol
-mword-relocations @gol
-mfix-cortex-m3-ldrd @gol
--munaligned-access}
+-munaligned-access @gol
+-mneon-for-64bits}
@emph{AVR Options}
@gccoptlist{-mmcu=@var{mcu} -maccumulate-args -mbranch-cost=@var{cost} @gol
@@ -11499,6 +11500,11 @@ setting of this option. If unaligned access is enabled then the
preprocessor symbol @code{__ARM_FEATURE_UNALIGNED} will also be
defined.
+@item -mneon-for-64bits
+@opindex mneon-for-64bits
+Enables using Neon to handle scalar 64-bits operations. This is
+disabled by default since the cost of moving data from core registers
+to Neon is high.
@end table
@node AVR Options
diff --git a/gcc/testsuite/gcc.target/arm/neon-for-64bits-1.c b/gcc/testsuite/gcc.target/arm/neon-for-64bits-1.c
new file mode 100644
index 0000000..a2a4103
--- /dev/null
+++ b/gcc/testsuite/gcc.target/arm/neon-for-64bits-1.c
@@ -0,0 +1,54 @@
+/* Check that Neon is *not* used by default to handle 64-bits scalar
+ operations. */
+
+/* { dg-do compile } */
+/* { dg-require-effective-target arm_neon_ok } */
+/* { dg-options "-O2" } */
+/* { dg-add-options arm_neon } */
+
+typedef long long i64;
+typedef unsigned long long u64;
+typedef unsigned int u32;
+typedef int i32;
+
+/* Unary operators */
+#define UNARY_OP(name, op) \
+ void unary_##name(u64 *a, u64 *b) { *a = op (*b + 0x1234567812345678ULL) ; }
+
+/* Binary operators */
+#define BINARY_OP(name, op) \
+ void binary_##name(u64 *a, u64 *b, u64 *c) { *a = *b op *c ; }
+
+/* Unsigned shift */
+#define SHIFT_U(name, op, amount) \
+ void ushift_##name(u64 *a, u64 *b, int c) { *a = *b op amount; }
+
+/* Signed shift */
+#define SHIFT_S(name, op, amount) \
+ void sshift_##name(i64 *a, i64 *b, int c) { *a = *b op amount; }
+
+UNARY_OP(not, ~)
+
+BINARY_OP(add, +)
+BINARY_OP(sub, -)
+BINARY_OP(and, &)
+BINARY_OP(or, |)
+BINARY_OP(xor, ^)
+
+SHIFT_U(right1, >>, 1)
+SHIFT_U(right2, >>, 2)
+SHIFT_U(right5, >>, 5)
+SHIFT_U(rightn, >>, c)
+
+SHIFT_S(right1, >>, 1)
+SHIFT_S(right2, >>, 2)
+SHIFT_S(right5, >>, 5)
+SHIFT_S(rightn, >>, c)
+
+/* { dg-final {scan-assembler-times "vmvn" 0} } */
+/* { dg-final {scan-assembler-times "vadd" 0} } */
+/* { dg-final {scan-assembler-times "vsub" 0} } */
+/* { dg-final {scan-assembler-times "vand" 0} } */
+/* { dg-final {scan-assembler-times "vorr" 0} } */
+/* { dg-final {scan-assembler-times "veor" 0} } */
+/* { dg-final {scan-assembler-times "vshr" 0} } */
diff --git a/gcc/testsuite/gcc.target/arm/neon-for-64bits-2.c b/gcc/testsuite/gcc.target/arm/neon-for-64bits-2.c
new file mode 100644
index 0000000..035bfb7
--- /dev/null
+++ b/gcc/testsuite/gcc.target/arm/neon-for-64bits-2.c
@@ -0,0 +1,57 @@
+/* Check that Neon is used to handle 64-bits scalar operations. */
+
+/* { dg-do compile } */
+/* { dg-require-effective-target arm_neon_ok } */
+/* { dg-options "-O2 -mneon-for-64bits" } */
+/* { dg-add-options arm_neon } */
+
+typedef long long i64;
+typedef unsigned long long u64;
+typedef unsigned int u32;
+typedef int i32;
+
+/* Unary operators */
+#define UNARY_OP(name, op) \
+ void unary_##name(u64 *a, u64 *b) { *a = op (*b + 0x1234567812345678ULL) ; }
+
+/* Binary operators */
+#define BINARY_OP(name, op) \
+ void binary_##name(u64 *a, u64 *b, u64 *c) { *a = *b op *c ; }
+
+/* Unsigned shift */
+#define SHIFT_U(name, op, amount) \
+ void ushift_##name(u64 *a, u64 *b, int c) { *a = *b op amount; }
+
+/* Signed shift */
+#define SHIFT_S(name, op, amount) \
+ void sshift_##name(i64 *a, i64 *b, int c) { *a = *b op amount; }
+
+UNARY_OP(not, ~)
+
+BINARY_OP(add, +)
+BINARY_OP(sub, -)
+BINARY_OP(and, &)
+BINARY_OP(or, |)
+BINARY_OP(xor, ^)
+
+SHIFT_U(right1, >>, 1)
+SHIFT_U(right2, >>, 2)
+SHIFT_U(right5, >>, 5)
+SHIFT_U(rightn, >>, c)
+
+SHIFT_S(right1, >>, 1)
+SHIFT_S(right2, >>, 2)
+SHIFT_S(right5, >>, 5)
+SHIFT_S(rightn, >>, c)
+
+/* { dg-final {scan-assembler-times "vmvn" 1} } */
+/* Two vadd: 1 in unary_not, 1 in binary_add */
+/* { dg-final {scan-assembler-times "vadd" 2} } */
+/* { dg-final {scan-assembler-times "vsub" 1} } */
+/* { dg-final {scan-assembler-times "vand" 1} } */
+/* { dg-final {scan-assembler-times "vorr" 1} } */
+/* { dg-final {scan-assembler-times "veor" 1} } */
+/* 6 vshr for right shifts by constant, and variable right shift uses
+ vshl with a negative amount in register. */
+/* { dg-final {scan-assembler-times "vshr" 6} } */
+/* { dg-final {scan-assembler-times "vshl" 2} } */
More information about the Gcc-patches
mailing list