Hi Andi!
On 2024-08-02T14:12:59-0700, Andi Kleen <a...@linux.intel.com> wrote:
> Andi Kleen <a...@linux.intel.com> writes:
>> This is a new attempt to fix PR116080. The previous try was reverted
>> because it just broke a bunch of tests, hiding the problem.
>
> The previous version still had one failure on powerpc because
> of a template call that needs a dg-error check for external_tail_call.
> I fixed that now in the below version.
>
> Okay for trunk? I would like to check that one in to avoid the noise
> in the regression reports.
I've tested this version in a few trees.
('-Wc++-compat' are the C test cases, '-std=c++YY' the C++ ones.)
For x86_64 GNU/Linux, '-m32' testing, this does resolve the previous
FAILs:
[-FAIL:-]{+UNSUPPORTED:+} c-c++-common/musttail12.c -std=c++11[-(test for
excess errors)-]
[-FAIL:-]{+UNSUPPORTED:+} c-c++-common/musttail12.c -std=c++17[-(test for
excess errors)-]
[-FAIL:-]{+UNSUPPORTED:+} c-c++-common/musttail12.c -std=c++26[-(test for
excess errors)-]
[-FAIL:-]{+UNSUPPORTED:+} g++.dg/musttail6.C[-(test for excess errors)-]
..., but also "regresses" (PASS -> UNSUPPORTED):
[-PASS:-]{+UNSUPPORTED:+} c-c++-common/musttail12.c -Wc++-compat[-(test
for excess errors)-]
[-PASS: c-c++-common/musttail3.c -Wc++-compat (test for errors, line 26)-]
[-PASS:-]{+UNSUPPORTED:+} c-c++-common/musttail3.c -Wc++-compat[-(test for
excess errors)-]
[-PASS: c-c++-common/musttail3.c -std=c++11 (test for errors, line 26)-]
[-PASS:-]{+UNSUPPORTED:+} c-c++-common/musttail3.c -std=c++11[-(test for
excess errors)-]
[-PASS: c-c++-common/musttail3.c -std=c++17 (test for errors, line 26)-]
[-PASS:-]{+UNSUPPORTED:+} c-c++-common/musttail3.c -std=c++17[-(test for
excess errors)-]
[-PASS: c-c++-common/musttail3.c -std=c++26 (test for errors, line 26)-]
[-PASS:-]{+UNSUPPORTED:+} c-c++-common/musttail3.c -std=c++26[-(test for
excess errors)-]
That's because of effective-target 'struct_musttail' for '-m32'
reporting:
struct_musttail1494739.cc: In function 'foo bar()':
struct_musttail1494739.cc:5:88: error: cannot tail-call: return value used
after call
(I'm just mentioning the latter "regressions" in case those are
unexpected.)
For powerpc64le GNU/Linux, this does resolve the previous FAIL:
PASS: g++.dg/musttail10.C (test for errors, line 11)
{+PASS: g++.dg/musttail10.C (test for errors, line 15)+}
PASS: g++.dg/musttail10.C (test for errors, line 20)
PASS: g++.dg/musttail10.C (test for errors, line 24)
PASS: g++.dg/musttail10.C (test for errors, line 7)
[-FAIL:-]{+PASS:+} g++.dg/musttail10.C (test for excess errors)
..., but similarly "regresses" (PASS -> UNSUPPORTED):
[-PASS:-]{+UNSUPPORTED:+} c-c++-common/musttail12.c -Wc++-compat[-(test
for excess errors)-]
[-PASS:-]{+UNSUPPORTED:+} c-c++-common/musttail12.c -std=c++11[-(test for
excess errors)-]
[-PASS:-]{+UNSUPPORTED:+} c-c++-common/musttail12.c -std=c++17[-(test for
excess errors)-]
[-PASS:-]{+UNSUPPORTED:+} c-c++-common/musttail12.c -std=c++26[-(test for
excess errors)-]
[-PASS: c-c++-common/musttail3.c -Wc++-compat (test for errors, line 26)-]
[-PASS:-]{+UNSUPPORTED:+} c-c++-common/musttail3.c -Wc++-compat[-(test for
excess errors)-]
[-PASS: c-c++-common/musttail3.c -std=c++11 (test for errors, line 26)-]
[-PASS:-]{+UNSUPPORTED:+} c-c++-common/musttail3.c -std=c++11[-(test for
excess errors)-]
[-PASS: c-c++-common/musttail3.c -std=c++17 (test for errors, line 26)-]
[-PASS:-]{+UNSUPPORTED:+} c-c++-common/musttail3.c -std=c++17[-(test for
excess errors)-]
[-PASS: c-c++-common/musttail3.c -std=c++26 (test for errors, line 26)-]
[-PASS:-]{+UNSUPPORTED:+} c-c++-common/musttail3.c -std=c++26[-(test for
excess errors)-]
Here, that's because of effective-target 'struct_musttail' reporting:
struct_musttail485321.cc: In function 'foo bar()':
struct_musttail485321.cc:5:88: error: cannot tail-call: target is not able
to optimize the call into a sibling call
(Again, I'm just mentioning the latter "regressions" in case those are
unexpected.)
So: looks good, all FAILs resolved (in these GCC configurations).
Grüße
Thomas
> This is a new attempt to fix PR116080. The previous try was reverted
> because it just broke a bunch of tests, hiding the problem.
>
> - musttail behaves differently than tailcall at -O0. Some of the test
> run at -O0, so add separate effective target tests for musttail.
> - New effective target tests need to use unique file names
> to make dejagnu caching work
> - Change the tests to use new targets
> - Add a external_musttail test to check for target's ability
> to do tail calls between translation units. This covers some powerpc
> ABIs.
>
> gcc/testsuite/ChangeLog:
>
> PR testsuite/116080
> * c-c++-common/musttail1.c: Use musttail target.
> * c-c++-common/musttail12.c: Use struct_musttail target.
> * c-c++-common/musttail2.c: Use musttail target.
> * c-c++-common/musttail3.c: Likewise.
> * c-c++-common/musttail4.c: Likewise.
> * c-c++-common/musttail7.c: Likewise.
> * c-c++-common/musttail8.c: Likewise.
> * g++.dg/musttail10.C: Likewise. Replace powerpc checks with
> external_musttail.
> * g++.dg/musttail11.C: Use musttail target.
> * g++.dg/musttail6.C: Use musttail target. Replace powerpc
> checks with external_musttail.
> * g++.dg/musttail9.C: Use musttail target.
> * lib/target-supports.exp: Add musttail, struct_musttail,
> external_musttail targets. Remove optimization for musttail.
> Use unique file names for musttail.
> ---
> gcc/testsuite/c-c++-common/musttail1.c | 2 +-
> gcc/testsuite/c-c++-common/musttail12.c | 2 +-
> gcc/testsuite/c-c++-common/musttail2.c | 2 +-
> gcc/testsuite/c-c++-common/musttail3.c | 2 +-
> gcc/testsuite/c-c++-common/musttail4.c | 2 +-
> gcc/testsuite/c-c++-common/musttail7.c | 2 +-
> gcc/testsuite/c-c++-common/musttail8.c | 2 +-
> gcc/testsuite/g++.dg/musttail10.C | 6 ++---
> gcc/testsuite/g++.dg/musttail11.C | 2 +-
> gcc/testsuite/g++.dg/musttail6.C | 4 ++--
> gcc/testsuite/g++.dg/musttail9.C | 2 +-
> gcc/testsuite/lib/target-supports.exp | 30 ++++++++++++++++++++-----
> 12 files changed, 38 insertions(+), 20 deletions(-)
>
> diff --git a/gcc/testsuite/c-c++-common/musttail1.c
> b/gcc/testsuite/c-c++-common/musttail1.c
> index 74efcc2a0bc6..51549672e02a 100644
> --- a/gcc/testsuite/c-c++-common/musttail1.c
> +++ b/gcc/testsuite/c-c++-common/musttail1.c
> @@ -1,4 +1,4 @@
> -/* { dg-do compile { target { tail_call && { c || c++11 } } } } */
> +/* { dg-do compile { target { musttail && { c || c++11 } } } } */
> /* { dg-additional-options "-fdelayed-branch" { target sparc*-*-* } } */
>
> int __attribute__((noinline,noclone,noipa))
> diff --git a/gcc/testsuite/c-c++-common/musttail12.c
> b/gcc/testsuite/c-c++-common/musttail12.c
> index 4140bcd00950..475afc5af3f3 100644
> --- a/gcc/testsuite/c-c++-common/musttail12.c
> +++ b/gcc/testsuite/c-c++-common/musttail12.c
> @@ -1,4 +1,4 @@
> -/* { dg-do compile { target { struct_tail_call && { c || c++11 } } } } */
> +/* { dg-do compile { target { struct_musttail && { c || c++11 } } } } */
> /* { dg-additional-options "-fdelayed-branch" { target sparc*-*-* } } */
>
> struct str
> diff --git a/gcc/testsuite/c-c++-common/musttail2.c
> b/gcc/testsuite/c-c++-common/musttail2.c
> index 86f2c3d77404..1970c4edd670 100644
> --- a/gcc/testsuite/c-c++-common/musttail2.c
> +++ b/gcc/testsuite/c-c++-common/musttail2.c
> @@ -1,4 +1,4 @@
> -/* { dg-do compile { target { tail_call && { c || c++11 } } } } */
> +/* { dg-do compile { target { musttail && { c || c++11 } } } } */
>
> struct box { char field[256]; int i; };
>
> diff --git a/gcc/testsuite/c-c++-common/musttail3.c
> b/gcc/testsuite/c-c++-common/musttail3.c
> index ea9589c59ef2..7499fd6460b4 100644
> --- a/gcc/testsuite/c-c++-common/musttail3.c
> +++ b/gcc/testsuite/c-c++-common/musttail3.c
> @@ -1,4 +1,4 @@
> -/* { dg-do compile { target { tail_call && { c || c++11 } } } } */
> +/* { dg-do compile { target { struct_musttail && { c || c++11 } } } } */
>
> extern int foo2 (int x, ...);
>
> diff --git a/gcc/testsuite/c-c++-common/musttail4.c
> b/gcc/testsuite/c-c++-common/musttail4.c
> index 23f4b5e1cd68..bd6effa4b931 100644
> --- a/gcc/testsuite/c-c++-common/musttail4.c
> +++ b/gcc/testsuite/c-c++-common/musttail4.c
> @@ -1,4 +1,4 @@
> -/* { dg-do compile { target { tail_call && { c || c++11 } } } } */
> +/* { dg-do compile { target { musttail && { c || c++11 } } } } */
>
> struct box { char field[64]; int i; };
>
> diff --git a/gcc/testsuite/c-c++-common/musttail7.c
> b/gcc/testsuite/c-c++-common/musttail7.c
> index c753a3fe9b2a..d17cb71256d7 100644
> --- a/gcc/testsuite/c-c++-common/musttail7.c
> +++ b/gcc/testsuite/c-c++-common/musttail7.c
> @@ -1,4 +1,4 @@
> -/* { dg-do compile { target { tail_call && { c || c++11 } } } } */
> +/* { dg-do compile { target { musttail && { c || c++11 } } } } */
> /* { dg-additional-options "-fdelayed-branch" { target sparc*-*-* } } */
>
> void __attribute__((noipa)) f() {}
> diff --git a/gcc/testsuite/c-c++-common/musttail8.c
> b/gcc/testsuite/c-c++-common/musttail8.c
> index 9fa10e0b54c4..50ca1ac0dd48 100644
> --- a/gcc/testsuite/c-c++-common/musttail8.c
> +++ b/gcc/testsuite/c-c++-common/musttail8.c
> @@ -1,4 +1,4 @@
> -/* { dg-do compile { target { tail_call && { c || c++11 } } } } */
> +/* { dg-do compile { target { musttail && { c || c++11 } } } } */
>
> float f1(void);
>
> diff --git a/gcc/testsuite/g++.dg/musttail10.C
> b/gcc/testsuite/g++.dg/musttail10.C
> index ff7fcc7d8755..a43d8a6fde7e 100644
> --- a/gcc/testsuite/g++.dg/musttail10.C
> +++ b/gcc/testsuite/g++.dg/musttail10.C
> @@ -1,4 +1,4 @@
> -/* { dg-do compile { target { tail_call } } } */
> +/* { dg-do compile { target { musttail } } } */
> /* { dg-options "-std=gnu++11" } */
> /* { dg-additional-options "-fdelayed-branch" { target sparc*-*-* } } */
>
> @@ -8,11 +8,11 @@ double g() { [[gnu::musttail]] return f<int>(); } /* {
> dg-error "cannot tail-cal
>
> template <class T>
> __attribute__((noinline, noclone, noipa))
> -T g1() { [[gnu::musttail]] return f<T>(); } /* { dg-error "target is not
> able" "" { target powerpc*-*-* } } */
> +T g1() { [[gnu::musttail]] return f<T>(); } /* { dg-error "target is not
> able" "" { target { ! external_musttail } } } */
>
> template <class T>
> __attribute__((noinline, noclone, noipa))
> -T g2() { [[gnu::musttail]] return f<T>(); }
> +T g2() { [[gnu::musttail]] return f<T>(); } /* { dg-error "target is not
> able" "" { target { ! external_musttail } } } */
>
> template <class T>
> __attribute__((noinline, noclone, noipa))
> diff --git a/gcc/testsuite/g++.dg/musttail11.C
> b/gcc/testsuite/g++.dg/musttail11.C
> index 1779e3287a93..dca87247d504 100644
> --- a/gcc/testsuite/g++.dg/musttail11.C
> +++ b/gcc/testsuite/g++.dg/musttail11.C
> @@ -1,4 +1,4 @@
> -/* { dg-do compile { target { tail_call } } } */
> +/* { dg-do compile { target { musttail } } } */
> /* { dg-options "-std=gnu++11" } */
> /* { dg-additional-options "-fdelayed-branch" { target sparc*-*-* } } */
>
> diff --git a/gcc/testsuite/g++.dg/musttail6.C
> b/gcc/testsuite/g++.dg/musttail6.C
> index 5c6f69407ddb..5dcf302139ae 100644
> --- a/gcc/testsuite/g++.dg/musttail6.C
> +++ b/gcc/testsuite/g++.dg/musttail6.C
> @@ -1,6 +1,6 @@
> -/* { dg-do compile { target { struct_tail_call } } } */
> +/* { dg-do compile { target { struct_musttail } } } */
> +/* { dg-require-effective-target external_musttail } */
> /* A lot of architectures will not build this due to PR115606 and PR115607 */
> -/* { dg-skip-if "powerpc does not support sibcall to templates" {
> powerpc*-*-* } } */
> /* { dg-options "-std=gnu++11" } */
> /* { dg-additional-options "-fdelayed-branch" { target sparc*-*-* } } */
>
> diff --git a/gcc/testsuite/g++.dg/musttail9.C
> b/gcc/testsuite/g++.dg/musttail9.C
> index fb0262e751be..85937dcdcd31 100644
> --- a/gcc/testsuite/g++.dg/musttail9.C
> +++ b/gcc/testsuite/g++.dg/musttail9.C
> @@ -1,4 +1,4 @@
> -/* { dg-do compile { target { tail_call } } } */
> +/* { dg-do compile { target { musttail } } } */
> /* { dg-options "-std=gnu++11" } */
> /* { dg-additional-options "-fdelayed-branch" { target sparc*-*-* } } */
>
> diff --git a/gcc/testsuite/lib/target-supports.exp
> b/gcc/testsuite/lib/target-supports.exp
> index d368251ef9a4..10b2969f747a 100644
> --- a/gcc/testsuite/lib/target-supports.exp
> +++ b/gcc/testsuite/lib/target-supports.exp
> @@ -12744,16 +12744,34 @@ proc check_effective_target_tail_call { } {
> } {-O2 -fdump-rtl-expand-all}] ;# The "SIBCALL" note requires a detailed
> dump.
> }
>
> -# Return 1 if the target can perform tail-call optimizations for structures
> +# Return 1 if the target can perform musttail optimizations of the
> +# most trivial type. This is separate from tail_call because musttail
> +# is supported at -O0.
> +proc check_effective_target_musttail { } {
> + return [check_no_messages_and_pattern musttail ",SIBCALL" rtl-expand {
> + __attribute__((__noipa__)) void foo (void) { }
> + __attribute__((__noipa__)) void bar (void) { [[gnu::musttail]] return
> foo(); }
> + } {-fdump-rtl-expand-all}] ;# The "SIBCALL" note requires a detailed
> dump.
> +}
> +
> +# Return 1 if the target can perform musttail for externals
> +proc check_effective_target_external_musttail { } {
> + return [check_no_messages_and_pattern external_musttail ",SIBCALL"
> rtl-expand {
> + extern __attribute__((__noipa__)) void foo (void);
> + __attribute__((__noipa__)) void bar (void) { [[gnu::musttail]] return
> foo(); }
> + } {-fdump-rtl-expand-all}] ;# The "SIBCALL" note requires a detailed
> dump.
> +}
> +
> +# Return 1 if the target can perform musttail optimizations for structures
> # checking with C++ because the C++ compiler has less tail call ability
> # due to PR115606 on some targets
> -proc check_effective_target_struct_tail_call { } {
> - return [check_no_messages_and_pattern tail_call ",SIBCALL" rtl-expand {
> +proc check_effective_target_struct_musttail { } {
> + return [check_no_messages_and_pattern struct_musttail ",SIBCALL"
> rtl-expand {
> // C++
> struct foo { int a, b; };
> - __attribute__((__noipa__)) struct foo foo (void) { return {}; }
> - __attribute__((__noipa__)) struct foo bar (void) { return foo(); }
> - } {-O2 -fdump-rtl-expand-all}] ;# The "SIBCALL" note requires a detailed
> dump.
> + extern __attribute__((__noipa__)) struct foo foo (void);
> + __attribute__((__noipa__)) struct foo bar (void) { [[gnu::musttail]]
> return foo(); }
> + } {-fdump-rtl-expand-all}] ;# The "SIBCALL" note requires a detailed
> dump.
> }
>
> # Return 1 if the target's calling sequence or its ABI
> --
> 2.45.2
