[ARM] Add -mbranch-cost option, and update a few tests

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  • [ARM] Add -mbranch-cost option, and update a few tests
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Commit Message

Christophe Lyon Oct. 23, 2017, 12:30 p.m.
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.lyon@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.lyon@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.lyon@linaro.org>
Date:   Fri Sep 8 12:27:42 2017 +0000

    Add -mbranch-cost=N option for ARM.
    
    Change-Id: I4d570646c405f7b186d0d1be80ce1661ef022aea

Comments

Jakub Jelinek Jan. 10, 2018, 2:44 p.m. | #1
On Mon, Oct 23, 2017 at 02:30:24PM +0200, Christophe Lyon wrote:
> 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) ?


Let's change all and watch the effects on all targets in testresults,
we can fine tune later on.

Does pr21643.c really fail somewhere on arm*?  Tried -mcpu=cortex-a5
and don't see the failure in x86_64-linux -> armv7a-hardfloat-linux-gnueabi
cross.


> gcc/ChangeLog:

> 

> 2017-10-23  Christophe Lyon  <christophe.lyon@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.lyon@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.


Ok for trunk.

Note, unreviewed patches should be pinged from time to time.

	Jakub
Christophe Lyon Jan. 10, 2018, 3:17 p.m. | #2
On 10 January 2018 at 15:44, Jakub Jelinek <jakub@redhat.com> wrote:
> On Mon, Oct 23, 2017 at 02:30:24PM +0200, Christophe Lyon wrote:

>> 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) ?

>

> Let's change all and watch the effects on all targets in testresults,

> we can fine tune later on.

>

OK, thanks

> Does pr21643.c really fail somewhere on arm*?  Tried -mcpu=cortex-a5

> and don't see the failure in x86_64-linux -> armv7a-hardfloat-linux-gnueabi

> cross.


Yes, for me still fails on arm-none-linux-gnueabihf
--with-cpu=cortex-a5 --with-fpu=vfpv3-d16-fp16

>

>> gcc/ChangeLog:

>>

>> 2017-10-23  Christophe Lyon  <christophe.lyon@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.lyon@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.

>

> Ok for trunk.

>

> Note, unreviewed patches should be pinged from time to time.

Sorry, I thought the patch was too crappy ;-)

Thanks,

Christophe

>

>         Jakub
Rainer Orth Jan. 12, 2018, 9:25 a.m. | #3
Hi Christophe,

> On 10 January 2018 at 15:44, Jakub Jelinek <jakub@redhat.com> wrote:

>> On Mon, Oct 23, 2017 at 02:30:24PM +0200, Christophe Lyon wrote:

>>> 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) ?

>>

>> Let's change all and watch the effects on all targets in testresults,

>> we can fine tune later on.

>>

> OK, thanks

>

>> Does pr21643.c really fail somewhere on arm*?  Tried -mcpu=cortex-a5

>> and don't see the failure in x86_64-linux -> armv7a-hardfloat-linux-gnueabi

>> cross.

>

> Yes, for me still fails on arm-none-linux-gnueabihf

> --with-cpu=cortex-a5 --with-fpu=vfpv3-d16-fp16

>

>>

>>> gcc/ChangeLog:

>>>

>>> 2017-10-23  Christophe Lyon  <christophe.lyon@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.lyon@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.

>>

>> Ok for trunk.

>>

>> Note, unreviewed patches should be pinged from time to time.

> Sorry, I thought the patch was too crappy ;-)


not at all, but it has two problems:

* The new branch_cost effective-target keyword needs documenting in
  sourcebuild.texi, as always.

* The patch caused a regression on non-Linux x86 targets:

FAIL: gcc.dg/tree-ssa/phi-opt-2.c scan-tree-dump-times optimized "if" 1 (found 0 times)

  I'm seeing this on i386-pc-solaris2.*, and according to
  gcc-testresults it happens on *86-*-freebsd*, too.  The reason is
  simple: while the original testcase enabled -mbranch-cost for all
  i?86-*-* and x86_64-*-* targets, the new branch_cost keyword does so
  only for i?86-*-linux* and x86_64-*-linux* for no reason I can see.
  Fixing that lets the test PASS on Solaris/x86, too, so I'm installing
  the following patch.

	Rainer

-- 
-----------------------------------------------------------------------------
Rainer Orth, Center for Biotechnology, Bielefeld University


2018-01-11  Rainer Orth  <ro@CeBiTec.Uni-Bielefeld.DE>

	* lib/target-supports.exp (check_effective_target_branch_cost):
	Accept all x86 targets.
# HG changeset patch
# Parent  76d1f957bcf2be744c67e2ff4587f00e87722cc9
Include all x86 targets in branch_cost effective target

diff --git a/gcc/testsuite/lib/target-supports.exp b/gcc/testsuite/lib/target-supports.exp
--- a/gcc/testsuite/lib/target-supports.exp
+++ b/gcc/testsuite/lib/target-supports.exp
@@ -8623,7 +8623,7 @@ proc check_effective_target_branch_cost 
 	 || [istarget avr*-*-*]
 	 || [istarget epiphany*-*-*]
 	 || [istarget frv*-*-*]
-	 || [istarget i?86-*-linux*] || [istarget x86_64-*-linux*]
+	 || [istarget i?86-*-*] || [istarget x86_64-*-*]
 	 || [istarget mips*-*-*]
 	 || [istarget s390*-*-*]
 	 || [istarget riscv*-*-*]
Christophe Lyon Jan. 12, 2018, 10:15 a.m. | #4
On 12 January 2018 at 10:25, Rainer Orth <ro@cebitec.uni-bielefeld.de> wrote:
> Hi Christophe,

>

>> On 10 January 2018 at 15:44, Jakub Jelinek <jakub@redhat.com> wrote:

>>> On Mon, Oct 23, 2017 at 02:30:24PM +0200, Christophe Lyon wrote:

>>>> 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) ?

>>>

>>> Let's change all and watch the effects on all targets in testresults,

>>> we can fine tune later on.

>>>

>> OK, thanks

>>

>>> Does pr21643.c really fail somewhere on arm*?  Tried -mcpu=cortex-a5

>>> and don't see the failure in x86_64-linux -> armv7a-hardfloat-linux-gnueabi

>>> cross.

>>

>> Yes, for me still fails on arm-none-linux-gnueabihf

>> --with-cpu=cortex-a5 --with-fpu=vfpv3-d16-fp16

>>

>>>

>>>> gcc/ChangeLog:

>>>>

>>>> 2017-10-23  Christophe Lyon  <christophe.lyon@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.lyon@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.

>>>

>>> Ok for trunk.

>>>

>>> Note, unreviewed patches should be pinged from time to time.

>> Sorry, I thought the patch was too crappy ;-)

>

> not at all, but it has two problems:

>

> * The new branch_cost effective-target keyword needs documenting in

>   sourcebuild.texi, as always.

>


Sorry, I keep forgetting this. How about the trivial attached patch? (I'm mainly
asking to check I add it to the most appropriate section)

> * The patch caused a regression on non-Linux x86 targets:

>

> FAIL: gcc.dg/tree-ssa/phi-opt-2.c scan-tree-dump-times optimized "if" 1 (found 0 times)

>

>   I'm seeing this on i386-pc-solaris2.*, and according to

>   gcc-testresults it happens on *86-*-freebsd*, too.  The reason is

>   simple: while the original testcase enabled -mbranch-cost for all

>   i?86-*-* and x86_64-*-* targets, the new branch_cost keyword does so

>   only for i?86-*-linux* and x86_64-*-linux* for no reason I can see.

>   Fixing that lets the test PASS on Solaris/x86, too, so I'm installing

>   the following patch.

>

Thanks for taking care of that, I can't remember why I added the *linux* part.

Christophe

>         Rainer

>

> --

> -----------------------------------------------------------------------------

> Rainer Orth, Center for Biotechnology, Bielefeld University

>

>

> 2018-01-11  Rainer Orth  <ro@CeBiTec.Uni-Bielefeld.DE>

>

>         * lib/target-supports.exp (check_effective_target_branch_cost):

>         Accept all x86 targets.

>
2018-01-12  Christophe Lyon  <christophe.lyon@linaro.org>

	* doc/sourcebuild.texi (Effective-Target Keywords, Other attributes):
	Add item for branch_cost.
diff --git a/gcc/doc/sourcebuild.texi b/gcc/doc/sourcebuild.texi
index f7de713..e4a3835 100644
--- a/gcc/doc/sourcebuild.texi
+++ b/gcc/doc/sourcebuild.texi
@@ -2133,6 +2133,9 @@ Target supports wide characters.
 @item automatic_stack_alignment
 Target supports automatic stack alignment.
 
+@item branch_cost
+Target supports @option{-branch-cost=N}.
+
 @item cxa_atexit
 Target uses @code{__cxa_atexit}.
Rainer Orth Jan. 12, 2018, 10:19 a.m. | #5
Hi Christophe,

>> not at all, but it has two problems:

>>

>> * The new branch_cost effective-target keyword needs documenting in

>>   sourcebuild.texi, as always.

>>

>

> Sorry, I keep forgetting this. How about the trivial attached patch? (I'm mainly

> asking to check I add it to the most appropriate section)


it can be non-trivial at times :-)

> 2018-01-12  Christophe Lyon  <christophe.lyon@linaro.org>

>

> 	* doc/sourcebuild.texi (Effective-Target Keywords, Other attributes):

> 	Add item for branch_cost.


Ok, thanks.

	Rainer

-- 
-----------------------------------------------------------------------------
Rainer Orth, Center for Biotechnology, Bielefeld University

Patch

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 } {