[Bug c/56140] New: GCC inlines incorrect function in __transaction_relaxed

[Bug c/56140] New: GCC inlines incorrect function in __transaction_relaxed

[srdjan.stipic at gmail dot com]

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: unassigned@gcc.gnu.org
        ReportedBy: srdjan.stipic@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'

[Bug middle-end/56140] GCC inlines incorrect function in __transaction_relaxed

[aldyh at gcc dot gnu.org]

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

Aldy Hernandez <aldyh at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
         AssignedTo|unassigned at gcc dot       |aldyh at gcc dot gnu.org
                   |gnu.org                     |

--- Comment #1 from Aldy Hernandez <aldyh at gcc dot gnu.org> 2013-02-15 19:46:13 UTC ---
Mine.

[Bug middle-end/56140] GCC inlines incorrect function in __transaction_relaxed

[aldyh at gcc dot gnu.org]

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

Aldy Hernandez <aldyh at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |RESOLVED
         Resolution|                            |FIXED

--- Comment #2 from Aldy Hernandez <aldyh at gcc dot gnu.org> 2013-02-21 20:35:40 UTC ---
With my patch for PR56108, since this transaction is obviously irrevocable, we
will no longer instrument the inlined code, thus fixing this PR as well.

Fixed in trunk.