[Bug inline-asm/60242] New: incorrect optimization of code with inline assembly

[Bug inline-asm/60242] New: incorrect optimization of code with inline assembly

[cerealguy at yandex dot ru]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=60242

            Bug ID: 60242
           Summary: incorrect optimization of code with inline assembly
           Product: gcc
           Version: 4.8.1
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: inline-asm
          Assignee: unassigned at gcc dot gnu.org
          Reporter: cerealguy at yandex dot ru

Created attachment 32153
  --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=32153&action=edit
An archive containing the source code and the .ii file

The attached code copies one array to another using inline assembly and outputs
the result. 
When compiled with -O2, the code that copies the data does not get executed.

----------------------------------------

Compiler version:

Using built-in specs.
COLLECT_GCC=g++
COLLECT_LTO_WRAPPER=/usr/lib/gcc/x86_64-linux-gnu/4.8/lto-wrapper
Target: x86_64-linux-gnu
Configured with: ../src/configure -v --with-pkgversion='Ubuntu/Linaro
4.8.1-10ubuntu9' --with-bugurl=file:///usr/share/doc/gcc-4.8/README.Bugs
--enable-languages=c,c++,java,go,d,fortran,objc,obj-c++ --prefix=/usr
--program-suffix=-4.8 --enable-shared --enable-linker-build-id
--libexecdir=/usr/lib --without-included-gettext --enable-threads=posix
--with-gxx-include-dir=/usr/include/c++/4.8 --libdir=/usr/lib --enable-nls
--with-sysroot=/ --enable-clocale=gnu --enable-libstdcxx-debug
--enable-libstdcxx-time=yes --enable-gnu-unique-object --enable-plugin
--with-system-zlib --disable-browser-plugin --enable-java-awt=gtk
--enable-gtk-cairo --with-java-home=/usr/lib/jvm/java-1.5.0-gcj-4.8-amd64/jre
--enable-java-home --with-jvm-root-dir=/usr/lib/jvm/java-1.5.0-gcj-4.8-amd64
--with-jvm-jar-dir=/usr/lib/jvm-exports/java-1.5.0-gcj-4.8-amd64
--with-arch-directory=amd64 --with-ecj-jar=/usr/share/java/eclipse-ecj.jar
--enable-objc-gc --enable-multiarch --disable-werror --with-arch-32=i686
--with-abi=m64 --with-multilib-list=m32,m64,mx32 --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 4.8.1 (Ubuntu/Linaro 4.8.1-10ubuntu9) 

----------------------------------------

Command line: g++ -O2 -o bug -save-temps bug.cpp && ./bug

[Bug inline-asm/60242] incorrect optimization of code with inline assembly

[rguenth at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=60242

Richard Biener <rguenth at gcc dot gnu.org> changed:

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

--- Comment #1 from Richard Biener <rguenth at gcc dot gnu.org> ---
You fail to tell GCC that your asm clobbers memory.

[Bug inline-asm/60242] incorrect optimization of code with inline assembly

[cerealguy at yandex dot ru]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=60242

cerealguy at yandex dot ru changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|RESOLVED                    |CLOSED

--- Comment #2 from cerealguy at yandex dot ru ---
(In reply to Richard Biener from comment #1)
> You fail to tell GCC that your asm clobbers memory.

Right