[r14-6559 Regression] FAIL: gcc.dg/guality/pr58791-4.c -Os -DPREVENT_OPTIMIZATION line pr58791-4.c:32 i == 486 on Linux/x86_64

2023-12-15 Thread haochen.jiang 
On Linux/x86_64,

8afdbcdd7abe1e3c7a81e07f34c256e7f2dbc652 is the first bad commit
commit 8afdbcdd7abe1e3c7a81e07f34c256e7f2dbc652
Author: Di Zhao 
Date:   Fri Dec 15 03:22:32 2023 +0800

Consider fully pipelined FMA in get_reassociation_width

caused

FAIL: gcc.dg/pr110279-2.c scan-tree-dump-not reassoc2 "was chosen for 
reassociation"
FAIL: gcc.dg/pr110279-2.c scan-tree-dump-times optimized "\\.FMA " 3

with GCC configured with

../../gcc/configure 
--prefix=/export/users/haochenj/src/gcc-bisect/master/master/r14-6559/usr 
--enable-clocale=gnu --with-system-zlib --with-demangler-in-ld 
--with-fpmath=sse --enable-languages=c,c++,fortran --enable-cet --without-isl 
--enable-libmpx x86_64-linux --disable-bootstrap

To reproduce:

$ cd {build_dir}/gcc && make check RUNTESTFLAGS="dg.exp=gcc.dg/pr110279-2.c 
--target_board='unix{-m32}'"
$ cd {build_dir}/gcc && make check RUNTESTFLAGS="dg.exp=gcc.dg/pr110279-2.c 
--target_board='unix{-m64}'"

(Please do not reply to this email, for question about this report, contact me 
at haochen dot jiang at intel.com)
(If you met problems with cascadelake related, disabling AVX512F in command 
line might save that.)
(However, please make sure that there is no potential problems with AVX512.)

Re: [r14-6559 Regression] FAIL: gcc.dg/guality/pr58791-4.c -Os -DPREVENT_OPTIMIZATION line pr58791-4.c:32 i == 486 on Linux/x86_64

2023-12-15 Thread Richard Biener 
On Fri, Dec 15, 2023 at 2:25 AM haochen.jiang
 wrote:
>
> On Linux/x86_64,
>
> 8afdbcdd7abe1e3c7a81e07f34c256e7f2dbc652 is the first bad commit
> commit 8afdbcdd7abe1e3c7a81e07f34c256e7f2dbc652
> Author: Di Zhao 
> Date:   Fri Dec 15 03:22:32 2023 +0800
>
> Consider fully pipelined FMA in get_reassociation_width
>
> caused
>
> FAIL: gcc.dg/guality/pr58791-4.c   -O2  -DPREVENT_OPTIMIZATION  line 
> pr58791-4.c:32 i2 == 487
> FAIL: gcc.dg/guality/pr58791-4.c   -O2  -DPREVENT_OPTIMIZATION  line 
> pr58791-4.c:32 i == 486
> FAIL: gcc.dg/guality/pr58791-4.c   -O2 -flto -fno-use-linker-plugin 
> -flto-partition=none  -DPREVENT_OPTIMIZATION line pr58791-4.c:32 i2 == 487
> FAIL: gcc.dg/guality/pr58791-4.c   -O2 -flto -fno-use-linker-plugin 
> -flto-partition=none  -DPREVENT_OPTIMIZATION line pr58791-4.c:32 i == 486
> FAIL: gcc.dg/guality/pr58791-4.c   -O2 -flto -fuse-linker-plugin 
> -fno-fat-lto-objects  -DPREVENT_OPTIMIZATION line pr58791-4.c:32 i2 == 487
> FAIL: gcc.dg/guality/pr58791-4.c   -O2 -flto -fuse-linker-plugin 
> -fno-fat-lto-objects  -DPREVENT_OPTIMIZATION line pr58791-4.c:32 i == 486
> FAIL: gcc.dg/guality/pr58791-4.c   -O3 -g  -DPREVENT_OPTIMIZATION  line 
> pr58791-4.c:32 i2 == 487
> FAIL: gcc.dg/guality/pr58791-4.c   -O3 -g  -DPREVENT_OPTIMIZATION  line 
> pr58791-4.c:32 i == 486
> FAIL: gcc.dg/guality/pr58791-4.c   -Os  -DPREVENT_OPTIMIZATION  line 
> pr58791-4.c:32 i2 == 487
> FAIL: gcc.dg/guality/pr58791-4.c   -Os  -DPREVENT_OPTIMIZATION  line 
> pr58791-4.c:32 i == 486
>
> with GCC configured with
>
> ../../gcc/configure 
> --prefix=/export/users/haochenj/src/gcc-bisect/master/master/r14-6559/usr 
> --enable-clocale=gnu --with-system-zlib --with-demangler-in-ld 
> --with-fpmath=sse --enable-languages=c,c++,fortran --enable-cet --without-isl 
> --enable-libmpx x86_64-linux --disable-bootstrap
>
> To reproduce:
>
> $ cd {build_dir}/gcc && make check 
> RUNTESTFLAGS="guality.exp=gcc.dg/guality/pr58791-4.c 
> --target_board='unix{-m64\ -march=cascadelake}'"

There's an extra intermediate stmt inserted (for much later use, but
reassoc inserts close to defs) that is
then also used for FMA forming.  This disturbs things in some way:

  g_5 = (double) f_4;
  # DEBUG g => g_5
  # DEBUG BEGIN_STMT
  h_7 = (double) b_6(D);
  # DEBUG h => h_7
  # DEBUG BEGIN_STMT
  _39 = h_7 * 3.25e+0;
  # DEBUG D#5 => g_5 * h_7
  # DEBUG i => D#5
  # DEBUG BEGIN_STMT
  # DEBUG i2 => D#5 + 1.0e+0
  # DEBUG BEGIN_STMT
  # DEBUG D#8 => g_5 * _39
  _3 = .FMA (g_5, _39, h_7);

g_5 is dead after the FMA.  Interestingly removing the

  asm volatile (NOP : : : "memory");
  asm volatile (NOP : : : "memory");

lines fixes the regression because then we can TER the FMA, keeping
g_5 live for longer.

Richard.

[r14-6559 Regression] FAIL: gcc.dg/guality/pr58791-4.c -Os -DPREVENT_OPTIMIZATION line pr58791-4.c:32 i == 486 on Linux/x86_64

2023-12-14 Thread haochen.jiang 
On Linux/x86_64,

8afdbcdd7abe1e3c7a81e07f34c256e7f2dbc652 is the first bad commit
commit 8afdbcdd7abe1e3c7a81e07f34c256e7f2dbc652
Author: Di Zhao 
Date:   Fri Dec 15 03:22:32 2023 +0800

Consider fully pipelined FMA in get_reassociation_width

caused

FAIL: gcc.dg/guality/pr58791-4.c   -O2  -DPREVENT_OPTIMIZATION  line 
pr58791-4.c:32 i2 == 487
FAIL: gcc.dg/guality/pr58791-4.c   -O2  -DPREVENT_OPTIMIZATION  line 
pr58791-4.c:32 i == 486
FAIL: gcc.dg/guality/pr58791-4.c   -O2 -flto -fno-use-linker-plugin 
-flto-partition=none  -DPREVENT_OPTIMIZATION line pr58791-4.c:32 i2 == 487
FAIL: gcc.dg/guality/pr58791-4.c   -O2 -flto -fno-use-linker-plugin 
-flto-partition=none  -DPREVENT_OPTIMIZATION line pr58791-4.c:32 i == 486
FAIL: gcc.dg/guality/pr58791-4.c   -O2 -flto -fuse-linker-plugin 
-fno-fat-lto-objects  -DPREVENT_OPTIMIZATION line pr58791-4.c:32 i2 == 487
FAIL: gcc.dg/guality/pr58791-4.c   -O2 -flto -fuse-linker-plugin 
-fno-fat-lto-objects  -DPREVENT_OPTIMIZATION line pr58791-4.c:32 i == 486
FAIL: gcc.dg/guality/pr58791-4.c   -O3 -g  -DPREVENT_OPTIMIZATION  line 
pr58791-4.c:32 i2 == 487
FAIL: gcc.dg/guality/pr58791-4.c   -O3 -g  -DPREVENT_OPTIMIZATION  line 
pr58791-4.c:32 i == 486
FAIL: gcc.dg/guality/pr58791-4.c   -Os  -DPREVENT_OPTIMIZATION  line 
pr58791-4.c:32 i2 == 487
FAIL: gcc.dg/guality/pr58791-4.c   -Os  -DPREVENT_OPTIMIZATION  line 
pr58791-4.c:32 i == 486

with GCC configured with

../../gcc/configure 
--prefix=/export/users/haochenj/src/gcc-bisect/master/master/r14-6559/usr 
--enable-clocale=gnu --with-system-zlib --with-demangler-in-ld 
--with-fpmath=sse --enable-languages=c,c++,fortran --enable-cet --without-isl 
--enable-libmpx x86_64-linux --disable-bootstrap

To reproduce:

$ cd {build_dir}/gcc && make check 
RUNTESTFLAGS="guality.exp=gcc.dg/guality/pr58791-4.c --target_board='unix{-m64\ 
-march=cascadelake}'"

(Please do not reply to this email, for question about this report, contact me 
at haochen dot jiang at intel.com.)
(If you met problems with cascadelake related, disabling AVX512F in command 
line might save that.)
(However, please make sure that there is no potential problems with AVX512.)