Hi,
After Jakub's suggestion in PR82120 and PR81184, the attached patch
adds the -mbranch-cost option to the ARM target. My understanding
is that it's intended to be used internally for testing and does not
require user-facing documentation.
I have updated a few tests, validation on aarch64 & arm targets shows
no regression,
and a few improvements when targeting cortex-a5 or cortex-m3:
gcc.dg/tree-ssa/reassoc-3[3456].c now pass.
That being said, I'm not sure about the other targets for which I
changed the condition,
and I am also concerned by the fact that it has no impact on
gcc.dg/pr21643.c and gcc.dg/tree-ssa/phi-opt-11.c (PR81184).
Should I restrict my patch to the only tests where it has an impact
(gcc.dg/tree-ssa/reassoc-3[3456].c) ?
Thanks,
Christophe
gcc/ChangeLog:
2017-10-23 Christophe Lyon <christophe.l...@linaro.org>
* config/arm/arm.opt (-mbranch-cost): New option.
* config/arm/arm.h (BRANCH_COST): Take arm_branch_cost into
account.
gcc/testsuite/ChangeLog:
2017-10-23 Christophe Lyon <christophe.l...@linaro.org>
* lib/target-supports.exp (check_effective_target_branch_cost):
New function.
* gcc.dg/builtin-bswap-7.c: Use branch_cost effective target.
* gcc.dg/pr21643.c: Likewise.
* gcc.dg/pr46309.c: Likewise.
* gcc.dg/tree-ssa/phi-opt-11.c: Likewise.
* gcc.dg/tree-ssa/phi-opt-2.c: Likewise.
* gcc.dg/tree-ssa/reassoc-32.c: Likewise.
* gcc.dg/tree-ssa/reassoc-33.c: Likewise.
* gcc.dg/tree-ssa/reassoc-34.c: Likewise.
* gcc.dg/tree-ssa/reassoc-35.c: Likewise.
* gcc.dg/tree-ssa/reassoc-36.c: Likewise.
* gcc.dg/tree-ssa/ssa-ifcombine-13.c: Likewise.
* gcc.dg/tree-ssa/ssa-ifcombine-ccmp-1.c: Likewise.
* gcc.dg/tree-ssa/ssa-ifcombine-ccmp-2.c: Likewise.
* gcc.dg/tree-ssa/ssa-ifcombine-ccmp-3.c: Likewise.
* gcc.dg/tree-ssa/ssa-ifcombine-ccmp-4.c: Likewise.
* gcc.dg/tree-ssa/ssa-ifcombine-ccmp-5.c: Likewise.
* gcc.dg/tree-ssa/ssa-ifcombine-ccmp-6.c: Likewise.
commit 0b21f80bf10d0273e6db4655654df9e125c0dae6
Author: Christophe Lyon <christophe.l...@linaro.org>
Date: Fri Sep 8 12:27:42 2017 +0000
Add -mbranch-cost=N option for ARM.
Change-Id: I4d570646c405f7b186d0d1be80ce1661ef022aea
diff --git a/gcc/config/arm/arm.h b/gcc/config/arm/arm.h
index 2d71e8f..854c753 100644
--- a/gcc/config/arm/arm.h
+++ b/gcc/config/arm/arm.h
@@ -1946,8 +1946,9 @@ enum arm_auto_incmodes
/* Try to generate sequences that don't involve branches, we can then use
conditional instructions. */
-#define BRANCH_COST(speed_p, predictable_p) \
- (current_tune->branch_cost (speed_p, predictable_p))
+#define BRANCH_COST(speed_p, predictable_p) \
+ ((arm_branch_cost != -1) ? arm_branch_cost : \
+ (current_tune->branch_cost (speed_p, predictable_p)))
/* False if short circuit operation is preferred. */
#define LOGICAL_OP_NON_SHORT_CIRCUIT \
diff --git a/gcc/config/arm/arm.opt b/gcc/config/arm/arm.opt
index 6060516..a3719cb 100644
--- a/gcc/config/arm/arm.opt
+++ b/gcc/config/arm/arm.opt
@@ -294,3 +294,7 @@ When linking for big-endian targets, generate a BE8 format
image.
mbe32
Target Report RejectNegative Negative(mbe8) InverseMask(BE8)
When linking for big-endian targets, generate a legacy BE32 format image.
+
+mbranch-cost=
+Target RejectNegative Joined UInteger Var(arm_branch_cost) Init(-1)
+Cost to assume for a branch insn.
diff --git a/gcc/testsuite/gcc.dg/builtin-bswap-7.c
b/gcc/testsuite/gcc.dg/builtin-bswap-7.c
index 3e1718d..fe85441 100644
--- a/gcc/testsuite/gcc.dg/builtin-bswap-7.c
+++ b/gcc/testsuite/gcc.dg/builtin-bswap-7.c
@@ -5,7 +5,7 @@
/* The branch cost setting prevents the return value from being
calculated with arithmetic instead of doing a compare. */
-/* { dg-additional-options "-mbranch-cost=0" { target s390x-*-* } } */
+/* { dg-additional-options "-mbranch-cost=0" { target branch_cost } } */
#include <stdint.h>
diff --git a/gcc/testsuite/gcc.dg/pr21643.c b/gcc/testsuite/gcc.dg/pr21643.c
index bd76aa8..d981fbc 100644
--- a/gcc/testsuite/gcc.dg/pr21643.c
+++ b/gcc/testsuite/gcc.dg/pr21643.c
@@ -1,6 +1,7 @@
/* PR tree-optimization/21643 */
/* { dg-do compile } */
/* { dg-options "-O2 -fdump-tree-reassoc1-details" } */
+/* { dg-additional-options "-mbranch-cost=2" { target branch_cost } } */
int
f1 (unsigned char c)
diff --git a/gcc/testsuite/gcc.dg/pr46309.c b/gcc/testsuite/gcc.dg/pr46309.c
index 68229cf..c964529 100644
--- a/gcc/testsuite/gcc.dg/pr46309.c
+++ b/gcc/testsuite/gcc.dg/pr46309.c
@@ -4,7 +4,7 @@
/* The transformation depends on BRANCH_COST being greater than 1
(see the notes in the PR), so try to force that. */
/* { dg-additional-options "-mtune=octeon2" { target mips*-*-* } } */
-/* { dg-additional-options "-mbranch-cost=2" { target avr*-*-* s390*-*-*
i?86-*-* x86_64-*-* } } */
+/* { dg-additional-options "-mbranch-cost=2" { target branch_cost } } */
int
f1 (int a)
diff --git a/gcc/testsuite/gcc.dg/tree-ssa/phi-opt-11.c
b/gcc/testsuite/gcc.dg/tree-ssa/phi-opt-11.c
index cda3abf..20728fc 100644
--- a/gcc/testsuite/gcc.dg/tree-ssa/phi-opt-11.c
+++ b/gcc/testsuite/gcc.dg/tree-ssa/phi-opt-11.c
@@ -1,5 +1,6 @@
/* { dg-do compile } */
/* { dg-options "-O1 -fdump-tree-optimized" } */
+/* { dg-additional-options "-mbranch-cost=2" { target branch_cost } } */
int f(int a, int b, int c)
{
diff --git a/gcc/testsuite/gcc.dg/tree-ssa/phi-opt-2.c
b/gcc/testsuite/gcc.dg/tree-ssa/phi-opt-2.c
index 1408122..e0b2618 100644
--- a/gcc/testsuite/gcc.dg/tree-ssa/phi-opt-2.c
+++ b/gcc/testsuite/gcc.dg/tree-ssa/phi-opt-2.c
@@ -1,6 +1,6 @@
/* { dg-do compile } */
/* { dg-options "-O1 -fdump-tree-optimized" } */
-/* { dg-additional-options "-mbranch-cost=1" { target { i?86-*-* x86_64-*-*
mips*-*-* s390*-*-* avr*-*-* } } } */
+/* { dg-additional-options "-mbranch-cost=1" { target branch_cost } } */
_Bool f1(_Bool a, _Bool b)
{
diff --git a/gcc/testsuite/gcc.dg/tree-ssa/reassoc-32.c
b/gcc/testsuite/gcc.dg/tree-ssa/reassoc-32.c
index 3ac1fb6..b6ca8e2 100644
--- a/gcc/testsuite/gcc.dg/tree-ssa/reassoc-32.c
+++ b/gcc/testsuite/gcc.dg/tree-ssa/reassoc-32.c
@@ -1,7 +1,7 @@
/* { dg-do run { target { ! "m68k*-*-* mmix*-*-* bfin*-*-* v850*-*-*
moxie*-*-* cris*-*-* m32c*-*-* fr30*-*-* mcore*-*-* powerpc*-*-* xtensa*-*-*"}
} } */
/* { dg-options "-O2 -fno-inline -fdump-tree-reassoc1-details" } */
-/* { dg-additional-options "-mbranch-cost=2" { target mips*-*-* avr-*-*
s390*-*-* i?86-*-* x86_64-*-* } } */
+/* { dg-additional-options "-mbranch-cost=2" { target branch_cost } } */
int test (int a, int b, int c)
diff --git a/gcc/testsuite/gcc.dg/tree-ssa/reassoc-33.c
b/gcc/testsuite/gcc.dg/tree-ssa/reassoc-33.c
index 6811a42..5572df4 100644
--- a/gcc/testsuite/gcc.dg/tree-ssa/reassoc-33.c
+++ b/gcc/testsuite/gcc.dg/tree-ssa/reassoc-33.c
@@ -1,7 +1,7 @@
/* { dg-do run { target { ! "m68k*-*-* mmix*-*-* bfin*-*-* v850*-*-*
moxie*-*-* cris*-*-* m32c*-*-* fr30*-*-* mcore*-*-* powerpc*-*-* xtensa*-*-*
hppa*-*-* nios2*-*-*"} } } */
/* { dg-options "-O2 -fno-inline -fdump-tree-reassoc1-details" } */
-/* { dg-additional-options "-mbranch-cost=2" { target mips*-*-* avr-*-*
s390*-*-* i?86-*-* x86_64-*-* } } */
+/* { dg-additional-options "-mbranch-cost=2" { target branch_cost } } */
int test (int a, int b, int c)
{
diff --git a/gcc/testsuite/gcc.dg/tree-ssa/reassoc-34.c
b/gcc/testsuite/gcc.dg/tree-ssa/reassoc-34.c
index 523654d..9b45f1c 100644
--- a/gcc/testsuite/gcc.dg/tree-ssa/reassoc-34.c
+++ b/gcc/testsuite/gcc.dg/tree-ssa/reassoc-34.c
@@ -1,7 +1,7 @@
/* { dg-do run { target { ! "m68k*-*-* mmix*-*-* bfin*-*-* v850*-*-*
moxie*-*-* cris*-*-* m32c*-*-* fr30*-*-* mcore*-*-* powerpc*-*-* xtensa*-*-*
hppa*-*-* nios2*-*-*"} } } */
/* { dg-options "-O2 -fno-inline -fdump-tree-reassoc1-details" } */
-/* { dg-additional-options "-mbranch-cost=2" { target mips*-*-* avr-*-*
s390*-*-* i?86-*-* x86_64-*-* } } */
+/* { dg-additional-options "-mbranch-cost=2" { target branch_cost } } */
int test (int a, int b, int c)
{
diff --git a/gcc/testsuite/gcc.dg/tree-ssa/reassoc-35.c
b/gcc/testsuite/gcc.dg/tree-ssa/reassoc-35.c
index 216604e..9ee3abc 100644
--- a/gcc/testsuite/gcc.dg/tree-ssa/reassoc-35.c
+++ b/gcc/testsuite/gcc.dg/tree-ssa/reassoc-35.c
@@ -1,7 +1,7 @@
/* { dg-do run { target { ! "m68k*-*-* mmix*-*-* bfin*-*-* v850*-*-*
moxie*-*-* cris*-*-* m32c*-*-* fr30*-*-* mcore*-*-* powerpc*-*-* xtensa*-*-*
hppa*-*-* nios2*-*-*"} } } */
/* { dg-options "-O2 -fno-inline -fdump-tree-reassoc1-details" } */
-/* { dg-additional-options "-mbranch-cost=2" { target mips*-*-* avr-*-*
s390*-*-* i?86-*-* x86_64-*-* } } */
+/* { dg-additional-options "-mbranch-cost=2" { target branch_cost } } */
int test (unsigned int a, int b, int c)
{
diff --git a/gcc/testsuite/gcc.dg/tree-ssa/reassoc-36.c
b/gcc/testsuite/gcc.dg/tree-ssa/reassoc-36.c
index dbbf8a1..ac3a042 100644
--- a/gcc/testsuite/gcc.dg/tree-ssa/reassoc-36.c
+++ b/gcc/testsuite/gcc.dg/tree-ssa/reassoc-36.c
@@ -1,7 +1,7 @@
/* { dg-do run { target { ! "m68k*-*-* mmix*-*-* bfin*-*-* v850*-*-*
moxie*-*-* cris*-*-* m32c*-*-* fr30*-*-* mcore*-*-* powerpc*-*-* xtensa*-*-*
hppa*-*-* nios2*-*-*"} } } */
/* { dg-options "-O2 -fno-inline -fdump-tree-reassoc1-details" } */
-/* { dg-additional-options "-mbranch-cost=2" { target mips*-*-* avr-*-*
s390*-*-* i?86-*-* x86_64-*-* } } */
+/* { dg-additional-options "-mbranch-cost=2" { target branch_cost } } */
int test (int a, int b, int c)
{
diff --git a/gcc/testsuite/gcc.dg/tree-ssa/ssa-ifcombine-13.c
b/gcc/testsuite/gcc.dg/tree-ssa/ssa-ifcombine-13.c
index 7f4f011..5f3147a 100644
--- a/gcc/testsuite/gcc.dg/tree-ssa/ssa-ifcombine-13.c
+++ b/gcc/testsuite/gcc.dg/tree-ssa/ssa-ifcombine-13.c
@@ -1,6 +1,6 @@
/* { dg-do compile } */
/* { dg-options "-O1 -fdump-tree-optimized-details-blocks" } */
-/* { dg-additional-options "-mbranch-cost=2" { target { i?86-*-* x86_64-*-*
s390*-*-* avr*-*-* } } } */
+/* { dg-additional-options "-mbranch-cost=2" { target branch_cost } } */
_Bool f1(_Bool a, _Bool b)
{
diff --git a/gcc/testsuite/gcc.dg/tree-ssa/ssa-ifcombine-ccmp-1.c
b/gcc/testsuite/gcc.dg/tree-ssa/ssa-ifcombine-ccmp-1.c
index acfcb7d..1714fcf 100644
--- a/gcc/testsuite/gcc.dg/tree-ssa/ssa-ifcombine-ccmp-1.c
+++ b/gcc/testsuite/gcc.dg/tree-ssa/ssa-ifcombine-ccmp-1.c
@@ -1,7 +1,7 @@
/* { dg-do compile { target { ! { { logical_op_short_circuit && { ! avr-*-* }
} || { m68k*-*-* mmix*-*-* bfin*-*-* v850*-*-* moxie*-*-* cris*-*-* m32c*-*-*
fr30*-*-* mcore*-*-* powerpc*-*-* xtensa*-*-* arc*-*-* mips*-*-* } } } } } */
/* { dg-options "-O2 -g -fdump-tree-optimized" } */
-/* { dg-additional-options "-mbranch-cost=2" { target mips*-*-* avr-*-*
s390*-*-* i?86-*-* x86_64-*-* } } */
+/* { dg-additional-options "-mbranch-cost=2" { target branch_cost } } */
int t (int a, int b)
{
diff --git a/gcc/testsuite/gcc.dg/tree-ssa/ssa-ifcombine-ccmp-2.c
b/gcc/testsuite/gcc.dg/tree-ssa/ssa-ifcombine-ccmp-2.c
index 0435d55..f35ec5e 100644
--- a/gcc/testsuite/gcc.dg/tree-ssa/ssa-ifcombine-ccmp-2.c
+++ b/gcc/testsuite/gcc.dg/tree-ssa/ssa-ifcombine-ccmp-2.c
@@ -1,7 +1,7 @@
/* { dg-do compile { target { ! { { logical_op_short_circuit && { ! avr-*-* }
} || { m68k*-*-* mmix*-*-* bfin*-*-* v850*-*-* moxie*-*-* cris*-*-* m32c*-*-*
fr30*-*-* mcore*-*-* powerpc*-*-* xtensa*-*-* arc*-*-* mips*-*-* } } } } } */
/* { dg-options "-O2 -g -fdump-tree-optimized" } */
-/* { dg-additional-options "-mbranch-cost=2" { target mips*-*-* avr-*-*
s390*-*-* i?86-*-* x86_64-*-* } } */
+/* { dg-additional-options "-mbranch-cost=2" { target branch_cost } } */
int t (int a, int b)
{
diff --git a/gcc/testsuite/gcc.dg/tree-ssa/ssa-ifcombine-ccmp-3.c
b/gcc/testsuite/gcc.dg/tree-ssa/ssa-ifcombine-ccmp-3.c
index 4f2b570..d84bdd5 100644
--- a/gcc/testsuite/gcc.dg/tree-ssa/ssa-ifcombine-ccmp-3.c
+++ b/gcc/testsuite/gcc.dg/tree-ssa/ssa-ifcombine-ccmp-3.c
@@ -1,7 +1,7 @@
/* { dg-do compile { target { ! { { logical_op_short_circuit && { ! avr-*-* }
} || { m68k*-*-* mmix*-*-* bfin*-*-* v850*-*-* moxie*-*-* cris*-*-* m32c*-*-*
fr30*-*-* mcore*-*-* powerpc*-*-* xtensa*-*-* arc*-*-* mips*-*-* } } } } } */
/* { dg-options "-O2 -g -fdump-tree-optimized" } */
-/* { dg-additional-options "-mbranch-cost=2" { target mips*-*-* avr-*-*
s390*-*-* i?86-*-* x86_64-*-* } } */
+/* { dg-additional-options "-mbranch-cost=2" { target branch_cost } } */
int t (int a, int b)
{
diff --git a/gcc/testsuite/gcc.dg/tree-ssa/ssa-ifcombine-ccmp-4.c
b/gcc/testsuite/gcc.dg/tree-ssa/ssa-ifcombine-ccmp-4.c
index 9c64b5e..be0ee26 100644
--- a/gcc/testsuite/gcc.dg/tree-ssa/ssa-ifcombine-ccmp-4.c
+++ b/gcc/testsuite/gcc.dg/tree-ssa/ssa-ifcombine-ccmp-4.c
@@ -1,7 +1,7 @@
/* { dg-do compile { target { ! { { logical_op_short_circuit && { ! avr-*-* }
} || { m68k*-*-* mmix*-*-* bfin*-*-* v850*-*-* moxie*-*-* cris*-*-* m32c*-*-*
fr30*-*-* mcore*-*-* powerpc*-*-* xtensa*-*-* arc*-*-* mips*-*-* } } } } } */
/* { dg-options "-O2 -g -fdump-tree-optimized" } */
-/* { dg-additional-options "-mbranch-cost=2" { target mips*-*-* avr-*-*
s390*-*-* i?86-*-* x86_64-*-* } } */
+/* { dg-additional-options "-mbranch-cost=2" { target branch_cost } } */
int t (int a, int b)
{
diff --git a/gcc/testsuite/gcc.dg/tree-ssa/ssa-ifcombine-ccmp-5.c
b/gcc/testsuite/gcc.dg/tree-ssa/ssa-ifcombine-ccmp-5.c
index 8cd4a60..09c22ab 100644
--- a/gcc/testsuite/gcc.dg/tree-ssa/ssa-ifcombine-ccmp-5.c
+++ b/gcc/testsuite/gcc.dg/tree-ssa/ssa-ifcombine-ccmp-5.c
@@ -1,7 +1,7 @@
/* { dg-do compile { target { ! { { logical_op_short_circuit && { ! avr-*-* }
} || { m68k*-*-* mmix*-*-* bfin*-*-* v850*-*-* moxie*-*-* cris*-*-* m32c*-*-*
fr30*-*-* mcore*-*-* powerpc*-*-* xtensa*-*-* arc*-*-* mips*-*-* } } } } } */
/* { dg-options "-O2 -g -fdump-tree-optimized" } */
-/* { dg-additional-options "-mbranch-cost=2" { target mips*-*-* avr-*-*
s390*-*-* i?86-*-* x86_64-*-* } } */
+/* { dg-additional-options "-mbranch-cost=2" { target branch_cost } } */
int t (int a, int b, int c)
{
diff --git a/gcc/testsuite/gcc.dg/tree-ssa/ssa-ifcombine-ccmp-6.c
b/gcc/testsuite/gcc.dg/tree-ssa/ssa-ifcombine-ccmp-6.c
index c161b16..a0dc82d 100644
--- a/gcc/testsuite/gcc.dg/tree-ssa/ssa-ifcombine-ccmp-6.c
+++ b/gcc/testsuite/gcc.dg/tree-ssa/ssa-ifcombine-ccmp-6.c
@@ -1,7 +1,7 @@
/* { dg-do compile { target { ! { { logical_op_short_circuit && { ! avr-*-* }
} || { m68k*-*-* mmix*-*-* bfin*-*-* v850*-*-* moxie*-*-* cris*-*-* m32c*-*-*
fr30*-*-* mcore*-*-* powerpc*-*-* xtensa*-*-* arc*-*-* mips*-*-* } } } } } */
/* { dg-options "-O2 -g -fdump-tree-optimized" } */
-/* { dg-additional-options "-mbranch-cost=2" { target mips*-*-* avr-*-*
s390*-*-* i?86-*-* x86_64-*-* } } */
+/* { dg-additional-options "-mbranch-cost=2" { target branch_cost } } */
int t (int a, int b, int c)
{
diff --git a/gcc/testsuite/lib/target-supports.exp
b/gcc/testsuite/lib/target-supports.exp
index 3ddc92e..8ffd1c4 100644
--- a/gcc/testsuite/lib/target-supports.exp
+++ b/gcc/testsuite/lib/target-supports.exp
@@ -8184,6 +8184,24 @@ proc check_effective_target_logical_op_short_circuit {} {
return 0
}
+# Return 1 if the target supports -mbranch-cost=N option.
+
+proc check_effective_target_branch_cost {} {
+ if { [ istarget arm*-*-*]
+ || [istarget avr*-*-*]
+ || [istarget epiphany*-*-*]
+ || [istarget frv*-*-*]
+ || [istarget i?86-*-linux*] || [istarget x86_64-*-linux*]
+ || [istarget mips*-*-*]
+ || [istarget s390*-*-*]
+ || [istarget riscv*-*-*]
+ || [istarget sh*-*-*]
+ || [istarget spu*-*-*] } {
+ return 1
+ }
+ return 0
+}
+
# Record that dg-final test TEST requires convential compilation.
proc force_conventional_output_for { test } {
