[Bug other/65794] New: Building crossback fails: No rule to make target `auto-build.h', needed by `build/genmddeps.o'

[Bug other/65794] New: Building crossback fails: No rule to make target `auto-build.h', needed by `build/genmddeps.o'

[gjl at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65794

            Bug ID: 65794
           Summary: Building crossback fails: No rule to make target
                    `auto-build.h', needed by `build/genmddeps.o'
           Product: gcc
           Version: 6.0
            Status: UNCONFIRMED
          Keywords: build
          Severity: normal
          Priority: P3
         Component: other
          Assignee: unassigned at gcc dot gnu.org
          Reporter: gjl at gcc dot gnu.org
              Host: i386-mingw32
            Target: x86_64-linux-gnu
             Build: x86_64-linux-gnu

GCC configured as:

../../gcc.gnu.org/trunk/configure --build=x86_64-linux-gnu --host=i386-mingw32
--enable-languages=c,c++ --target=x86_64-linux-gnu
--prefix=/home/georg/gnu/install/gcc-64-32-cross

with empty build and empty install directory.

Building the compiler aborts:

...
/usr/bin/msgfmt --statistics -o po/zh_TW.gmo
../../../gcc.gnu.org/trunk/gcc/po/zh_TW.po
3519 translated messages, 6759 fuzzy translations, 904 untranslated messages.
TARGET_CPU_DEFAULT="" \
        HEADERS="auto-host.h ansidecl.h config/i386/xm-mingw32.h" DEFINES="" \
        /bin/bash ../../../gcc.gnu.org/trunk/gcc/mkconfig.sh config.h
TARGET_CPU_DEFAULT="" \
        HEADERS="options.h insn-constants.h config/vxworks-dummy.h
config/i386/biarch64.h config/i386/i386.h config/i386/unix.h config/i386/att.h
config/dbxelf.h config/elfos.h config/gnu-user.h config/glibc-stdint.h
config/i386/x86-64.h config/i386/gnu-user-common.h config/i386/gnu-user64.h
config/linux.h config/linux-android.h config/i386/linux-common.h
config/i386/linux64.h config/initfini-array.h defaults.h" DEFINES="LIBC_GLIBC=1
LIBC_UCLIBC=2 LIBC_BIONIC=3 DEFAULT_LIBC=LIBC_GLIBC ANDROID_DEFAULT=0" \
        /bin/bash ../../../gcc.gnu.org/trunk/gcc/mkconfig.sh tm.h
TARGET_CPU_DEFAULT="" \
        HEADERS="config/i386/i386-protos.h config/linux-protos.h tm-preds.h"
DEFINES="" \
        /bin/bash ../../../gcc.gnu.org/trunk/gcc/mkconfig.sh tm_p.h
TARGET_CPU_DEFAULT="" \
        HEADERS="auto-build.h ansidecl.h" DEFINES="" \
        /bin/bash ../../../gcc.gnu.org/trunk/gcc/mkconfig.sh bconfig.h
make[2]: *** No rule to make target `auto-build.h', needed by
`build/genmddeps.o'.  Stop.
make[2]: Leaving directory `/data/home/georg/gnu/build/gcc-64-32-cross/gcc'
make[1]: *** [all-gcc] Error 2
make[1]: Leaving directory `/data/home/georg/gnu/build/gcc-64-32-cross'
make: *** [all] Error 2

The system has a i386-mingw32 toolchain installed, but presumably the above
problem occurs also with other crossback configuration with 

build = target != host

[Bug other/65794] Building crossback fails: No rule to make target `auto-build.h', needed by `build/genmddeps.o'

[saper at marcincieslak dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65794

Marcin Cieślak <saper at marcincieslak dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |saper at marcincieslak dot com

--- Comment #1 from Marcin Cieślak <saper at marcincieslak dot com> ---
I have the same problem on solaris 2.9 using GCC:

I am using gcc 4.9.3 (compiled as a 32-bit binary) to compile gcc 4.9.3 as a
64-bit binary:


env \
        BOOT_CFLAGS="-m64 -mcpu=ultrasparc3" \
        BOOT_CXXFLAGS="-m64 -mcpu=ultrasparc3" \
        CFLAGS="-m64 -mcpu=ultrasparc3" \
        CXXFLAGS="-m64 -mcpu=ultrasparc3" \
        CC=$HOME/sparcv7/bin/gcc \
        CXX=$HOME/sparcv7/bin/g++ \
        LD_LIBRARY_PATH=${LD_LIBRARY_PATH}:${HOME}/sparcv9/lib \
        AR="/usr/ccs/bin/ar" \
        RANLIB="/usr/ccs/bin/ranlib" \
        AS="/usr/ccs/bin/as" \
        $HOME/src/gcc-4.9.3/configure \
         --prefix=$HOME/sparcv9    \
         --with-gmp=$HOME/sparcv9  \
         --with-mpfr=$HOME/sparcv9 \
         --with-mpc=$HOME/sparcv9  \
         --with-isl=$HOME/sparcv9  \
         --with-cloog=$HOME/sparcv9  \
         --without-gnu-as --without-gnu-ld \
         --enable-languages=c,c++ --enable-obsolete \
         --host=sparc64-sun-solaris2.9 \
         --target=sparc64-sun-solaris2.9 \
         --build=sparc-sun-solaris2.9 \
         --disable-bootstrap


Failure:

make[2]: Entering directory '/home/admini/saper/build/gcc-4.9.3/gcc'
TARGET_CPU_DEFAULT="" \
HEADERS="auto-host.h ansidecl.h" DEFINES="" \
/bin/bash /home/admini/saper/src/gcc-4.9.3/gcc/mkconfig.sh config.h
TARGET_CPU_DEFAULT="TARGET_CPU_v9" \
HEADERS="options.h insn-constants.h config/sparc/default-64.h
config/sparc/biarch64.h config/vxworks-dummy.h config/sparc/sparc.h
config/dbxelf.h config/elfos.h config/sparc/sysv4.h config/sol2.h
config/sparc/sol2.h config/sol2-bi.h config/sparc/tso.h config/initfini-array.h
defaults.h" DEFINES="LIBC_GLIBC=1 LIBC_UCLIBC=2 LIBC_BIONIC=3" \
/bin/bash /home/admini/saper/src/gcc-4.9.3/gcc/mkconfig.sh tm.h
TARGET_CPU_DEFAULT="" \
HEADERS="config/sparc/sparc-protos.h config/sol2-protos.h tm-preds.h"
DEFINES="" \
/bin/bash /home/admini/saper/src/gcc-4.9.3/gcc/mkconfig.sh tm_p.h
TARGET_CPU_DEFAULT="" \
HEADERS="auto-build.h ansidecl.h" DEFINES="" \
/bin/bash /home/admini/saper/src/gcc-4.9.3/gcc/mkconfig.sh bconfig.h
make[2]: *** No rule to make target 'auto-build.h', needed by
'build/genmddeps.o'.  Stop.
make[2]: Leaving directory '/home/admini/saper/build/gcc-4.9.3/gcc'
Makefile:3972: recipe for target 'all-gcc' failed
make[1]: *** [all-gcc] Error 2
make[1]: Leaving directory '/home/admini/saper/build/gcc-4.9.3'
Makefile:859: recipe for target 'all' failed
make: *** [all] Error 2
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Subject: [Bug tree-optimization/67153] [5/6 Regression] integer optimizations 53% slower than std::bitset<>
Date: Sun, 16 Aug 2015 21:43:00 -0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?idg153

--- Comment #13 from ncm at cantrip dot org ---
This is essentially the entire difference between the versions of
puzzlegen-int.cc without, and with, the added "++count;" line
referenced above (modulo register assignments and branch labels)
that sidesteps the +50% pessimization:

(Asm is from "g++ -fverbose-asm -std=c++14 -O3 -Wall -S $SRC.cc" using
g++ (Debian 5.2.1-15) 5.2.1 20150808, with no instruction-set extensions
specified.  Output with "-mbmi -mbmi2" has different instructions, but
they do not noticeably affect run time on Haswell i7-4770.)

@@ -793,25 +793,26 @@
 .L141:
        movl    (%rdi), %esi    # MEM[base: _244, offset: 0], word
        testl   %r11d, %esi     # D.66634, word
        jne     .L138           #,
        xorl    %eax, %eax      # tmp419
        cmpl    %esi, %r12d     # word, seven
        leaq    208(%rsp), %rcx #, tmp574
        sete    %al             #, tmp419
        movl    %r12d, %edx     # seven, seven
        leal    1(%rax,%rax), %r8d      #, D.66619
        .p2align 4,,10
        .p2align 3
  .L140:
        movl    %edx, %eax      # seven, D.66634
        negl    %eax    # D.66634
        andl    %edx, %eax      # seven, D.66622
        testl   %eax, %esi      # D.66622, word
        je      .L139   #,
        addl    %r8d, 24(%rcx)  # D.66619, MEM[base: _207, offset: 24B]
+       addl    $1, %ebx        #, count
 .L139:
        notl    %eax            # D.66622
        subq    $4, %rcx        #, ivtmp.424
        andl    %eax, %edx      # D.66622, seven
        jne     .L140           #,
        addq    $4, %rdi        #, ivtmp.428
        cmpq    %rdi, %r10      # ivtmp.428, D.66637
        jne     .L141           #,

I tried a version of the program with a fixed-length loop (over
'place' in [6..0]) so that branches do not depend on results of
"rest &= ~-rest".  The compiler unrolled the loop, but the program
ran at pessimized speed with or without the "++count" line.

I am very curious whether this has been reproduced on others' Haswells,
and on Ivybridge and Skylake.

[Bug other/65794] Building crossback fails: No rule to make target `auto-build.h', needed by `build/genmddeps.o'

[saper at marcincieslak dot com]

[-- Warning: decoded text below may be mangled, UTF-8 assumed --]
[-- Attachment #1: Type: text/plain; charset="UTF-8", Size: 12310 bytes --]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65794

--- Comment #2 from Marcin Cieślak <saper at marcincieslak dot com> ---
Created attachment 36191
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=36191&action=edit
Patch to Makefile to proceed with the build

The attached patch allowed me to continue the build. Probably this patch is not
the correct fix though.

It can be applied to Makefile.in prior to the configure stage. It looks like
"config.status" has no special knowledge of the "auto-build.h" header.

(Basically in my case the generated files - auto-host.h and auto-build.h were
identical, except for the comment in line 1)
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Subject: [Bug c/67243] New: Wrong Message of -Wvla for Standard ISO C90 However Emitted with -stdÁ1
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67243

            Bug ID: 67243
           Summary: Wrong Message of -Wvla for Standard ISO C90 However
                    Emitted with -std=c11
           Product: gcc
           Version: 6.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c
          Assignee: unassigned at gcc dot gnu.org
          Reporter: chengniansun at gmail dot com
  Target Milestone: ---

When I compile the code "int array[4.3];", in addition to the error, GCC also
emits a -Wvla warning saying that ISO C90 forbids this. However, I specify
-std=c11 in the command line, and IMHO this is at least an inconsistency
between errors and error messages. 

$: cat t.c
int array[4.3];
$: gcc-trunk -c -Wvla -std=c11 -pedantic t.c
t.c:1:5: error: size of array ‘array’ has non-integer type
 int array[4.3];
     ^
t.c:1:1: warning: variably modified ‘array’ at file scope
 int array[4.3];
 ^
t.c:1:1: warning: ISO C90 forbids array ‘array’ whose size can’t be evaluated
[-Wvla]
$: gcc-trunk -v
Using built-in specs.
COLLECT_GCC=gcc-trunk
COLLECT_LTO_WRAPPER=/usr/local/gcc-trunk/libexec/gcc/x86_64-pc-linux-gnu/6.0.0/lto-wrapper
Target: x86_64-pc-linux-gnu
Configured with: ../gcc-trunk/configure
--enable-languages=c,c++,objc,obj-c++,fortran,lto --disable-werror
--with-gmp=/usr/local/gcc-trunk --with-mpfr=/usr/local/gcc-trunk
--with-mpc=/usr/local/gcc-trunk --with-cloog=/usr/local/gcc-trunk
--prefix=/usr/local/gcc-trunk
Thread model: posix
gcc version 6.0.0 20150815 (experimental) [trunk revision 226911] (GCC) 
$:
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Subject: [Bug c/67243] Wrong Message of -Wvla for Standard ISO C90 However Emitted with -stdÁ1
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67243

Manuel López-Ibáñez <manu at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
   Last reconfirmed|                            |2015-08-16
                 CC|                            |manu at gcc dot gnu.org
     Ever confirmed|0                           |1

--- Comment #1 from Manuel López-Ibáñez <manu at gcc dot gnu.org> ---
It is also useless to give such warning after such error.

I'm afraid the way GCC reports most extensions is very fragile in this way. It
doesn't affect only Wvla. It would be nice to discuss/design/agree on a
canonical and future-proof way to report:

* Pure GNU extensions, not accepted by any standard.
* Features accepted by some standard but that are extensions for other
standards (like C++ style comments).

The latter requires some future-proof way of reporting:

* Extensions that are forbidden up to a particular standard.

* Extensions that were accepted but are forbidden now (not sure if there is
such case at all).

(It is kind of ironic that Clang is fair more clear pointing out when something
is a "GNU extension". In some way, Clang is doing more promotion of GNU than
GCC!)
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Subject: [Bug c/67243] Wrong Message of -Wvla for Standard ISO C90 However Emitted with -stdÁ1
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67243

--- Comment #2 from Manuel López-Ibáñez <manu at gcc dot gnu.org> ---
Moreover, since VLAs are not an extension in C99, the text of Wvla is wrong
always for -std=c99. 

void square(int num) {
  int array[num];
}

With -std=c99 -Wpedantic there is no warning.
With -std=c99 -Wvla, it mentions ISO C90, which is irrelevant.
Clang just says: "variable length array used"
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https://gcc.gnu.org/bugzilla/show_bug.cgi?idg153

--- Comment #14 from ncm at cantrip dot org ---
A notable difference between g++-4.9 output and g++-5 output is that,
while both hoist the "(word == seven)" comparison out of the innermost
loop, gcc-4.9 splits inner loop into two versions, one that increments
scores by 3 and another that increments by 1, where g++-5 saves 3 or 1
into a register and uses the same inner loop for both cases.

Rewriting the critical loop
  - to run with separate inner loops
     - does not slow down the fast g++-4.9-compiled program, but
     - fails to speed up the slow g++-5-compiled program.
  - to precompute a 1 or 3 increment, with one inner loop for both cases
     - does slow down the previously fast g++-4.9-compiled program, and
     - does not change the speed of the slow g++-5-compiled program

[Bug other/65794] Building crossback fails: No rule to make target `auto-build.h', needed by `build/genmddeps.o'

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65794

Andrew Pinski <pinskia at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|---                         |10.0
         Resolution|---                         |FIXED
             Status|NEW                         |RESOLVED

--- Comment #6 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Fixed for GCC 10 by r10-4331.