http://gcc.gnu.org/bugzilla/show_bug.cgi?id=56140



             Bug #: 56140

           Summary: GCC inlines incorrect function in

                    __transaction_relaxed

    Classification: Unclassified

           Product: gcc

           Version: trans-mem

            Status: UNCONFIRMED

          Severity: minor

          Priority: P3

         Component: c

        AssignedTo: unassig...@gcc.gnu.org

        ReportedBy: srdjan.sti...@gmail.com





Created attachment 29301

  --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=29301

Test case.



BUG: GCC inlines tm_clone function in serial irrevocable transaction.

This is incorrect and causes the slowdown of irrevocable transactions.

The correct behavior it to inline non-instrumented function.



The bug is present in 4.7.2 and 4.8 (gcc version 4.8.0 20130129)

when compiling with -O1, -O2, -O3.



// examle.c

int a;



__attribute__((noinline))

void g() {

  asm("");

}



__attribute__((noinline))

void f1() {

  a++;

}



inline

void f2() {

  a++;

}



int main() {

  __transaction_relaxed {

    g();  // start transaction in irrevocable mode

    f1();

    f2(); // BUG: compiler inlines tm_clone of f2()

          // BUG FIX: compiler should inline original f2()

  }

  return 0;

}



Generated code:



g():

    ret

f1():

    addl    $1, a(%rip)

    ret

f2():

    addl    $1, a(%rip)

    ret

main:

    subq    $8, %rsp

    movl    $74, %edi

    xorl    %eax, %eax

    call    _ITM_beginTransaction

    call    g()

    call    f1()

    movl    $a, %edi

    call    _ITM_RfWU4

    leal    1(%rax), %esi

    movl    $a, %edi

    call    _ITM_WaWU4

    call    _ITM_commitTransaction

    xorl    %eax, %eax

    addq    $8, %rsp

    ret

a:

    .zero    4





Compiled with:



~# gcc-4.7 -v -O1 example.c -fgnu-tm -c

Using built-in specs.

COLLECT_GCC=gcc-4.7

Target: x86_64-linux-gnu

Configured with: ../src/configure -v --with-pkgversion='Ubuntu/Linaro

4.7.2-5ubuntu1' --with-bugurl=file:///usr/share/doc/gcc-4.7/README.Bugs

--enable-languages=c,c++,go,fortran,objc,obj-c++ --prefix=/usr

--program-suffix=-4.7 --enable-shared --enable-linker-build-id

--with-system-zlib --libexecdir=/usr/lib --without-included-gettext

--enable-threads=posix --with-gxx-include-dir=/usr/include/c++/4.7

--libdir=/usr/lib --enable-nls --with-sysroot=/ --enable-clocale=gnu

--enable-libstdcxx-debug --enable-libstdcxx-time=yes --enable-gnu-unique-object

--enable-plugin --enable-objc-gc --disable-werror --with-arch-32=i686

--with-tune=generic --enable-checking=release --build=x86_64-linux-gnu

--host=x86_64-linux-gnu --target=x86_64-linux-gnu

Thread model: posix

gcc version 4.7.2 (Ubuntu/Linaro 4.7.2-5ubuntu1) 

COLLECT_GCC_OPTIONS='-v' '-O1' '-fgnu-tm' '-c' '-mtune=generic' '-march=x86-64'

'-pthread'

 /usr/lib/gcc/x86_64-linux-gnu/4.7/cc1 -quiet -v -imultiarch x86_64-linux-gnu

-D_REENTRANT example.c -quiet -dumpbase example.c -mtune=generic -march=x86-64

-auxbase example -O1 -version -fgnu-tm -fstack-protector -o /tmp/ccC3mWQQ.s

GNU C (Ubuntu/Linaro 4.7.2-5ubuntu1) version 4.7.2 (x86_64-linux-gnu)

    compiled by GNU C version 4.7.2, GMP version 5.0.2, MPFR version 3.1.0-p3,

MPC version 0.9

GGC heuristics: --param ggc-min-expand=100 --param ggc-min-heapsize=131072

ignoring nonexistent directory "/usr/local/include/x86_64-linux-gnu"

ignoring nonexistent directory

"/usr/lib/gcc/x86_64-linux-gnu/4.7/../../../../x86_64-linux-gnu/include"

#include "..." search starts here:

#include <...> search starts here:

 /usr/lib/gcc/x86_64-linux-gnu/4.7/include

 /usr/local/include

 /usr/lib/gcc/x86_64-linux-gnu/4.7/include-fixed

 /usr/include/x86_64-linux-gnu

 /usr/include

End of search list.

GNU C (Ubuntu/Linaro 4.7.2-5ubuntu1) version 4.7.2 (x86_64-linux-gnu)

    compiled by GNU C version 4.7.2, GMP version 5.0.2, MPFR version 3.1.0-p3,

MPC version 0.9

GGC heuristics: --param ggc-min-expand=100 --param ggc-min-heapsize=131072

Compiler executable checksum: fbb4af59dce4dce949ee30395742b8d0

COLLECT_GCC_OPTIONS='-v' '-O1' '-fgnu-tm' '-c' '-mtune=generic' '-march=x86-64'

'-pthread'

 as -v --64 -o example.o /tmp/ccC3mWQQ.s

GNU assembler version 2.22.90 (x86_64-linux-gnu) using BFD version (GNU

Binutils for Ubuntu) 2.22.90.20120924

COMPILER_PATH=/usr/lib/gcc/x86_64-linux-gnu/4.7/:/usr/lib/gcc/x86_64-linux-gnu/4.7/:/usr/lib/gcc/x86_64-linux-gnu/:/usr/lib/gcc/x86_64-linux-gnu/4.7/:/usr/lib/gcc/x86_64-linux-gnu/

LIBRARY_PATH=/usr/lib/gcc/x86_64-linux-gnu/4.7/:/usr/lib/gcc/x86_64-linux-gnu/4.7/../../../x86_64-linux-gnu/:/usr/lib/gcc/x86_64-linux-gnu/4.7/../../../../lib/:/lib/x86_64-linux-gnu/:/lib/../lib/:/usr/lib/x86_64-linux-gnu/:/usr/lib/../lib/:/usr/lib/gcc/x86_64-linux-gnu/4.7/../../../:/lib/:/usr/lib/

COLLECT_GCC_OPTIONS='-v' '-O1' '-fgnu-tm' '-c' '-mtune=generic' '-march=x86-64'

'-pthread'

Reply via email to