[Bug c/17047] New: GCC incorrectly recognizes static vars when they are meet in asm blocks with -O2,-O3,-Os compiler options

[Bug c/17047] New: GCC incorrectly recognizes static vars when they are meet in asm blocks with -O2,-O3,-Os compiler options

[do8896 at db dot com]

GCC incorrectly parses such blocks:

static unsigned long long myVar=0x0LL;

static void myFunc(){
  asm volatile ("movq myVar, %mm3");
};

int main(){
  myFunc();
  return 0;
}

-------------------------
In the result in object file, which compiled with command: "gcc -O3 -c main.c -o
main.o",(-O3 may be substituted on -O2 or -Os (with -O1,-O0 it works correctly))
if I do "nm main.o", the result is:

00000000 T main
         U myVar

i.e. gcc thinks that myVar will be defined as extern, but it is static :(
and gcc main.o -o main fail with result:

main.o(.text+0x6): In function `main':
: undefined reference to `myVar'
collect2: ld returned 1 exit status
It error also in 3.3.2 version of GCC.

-- 
           Summary: GCC incorrectly recognizes static vars when they are
                    meet in asm blocks with -O2,-O3,-Os compiler options
           Product: gcc
           Version: 3.4.1
            Status: UNCONFIRMED
          Severity: normal
          Priority: P2
         Component: c
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: do8896 at db dot com
                CC: gcc-bugs at gcc dot gnu dot org
 GCC build triplet: i686-pc-linux-gnu
  GCC host triplet: i686-pc-linux-gnu
GCC target triplet: i686-pc-linux-gnu


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=17047

[Bug c/17047] GCC incorrectly recognizes static vars when they are meet in asm blocks with -O2,-O3,-Os compiler options

[do8896 at db dot com]

------- Additional Comments From do8896 at db dot com  2004-08-16 09:43 -------
Created an attachment (id=6935)
 --> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=6935&action=view)
file with example


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=17047

[Bug c/17047] GCC incorrectly recognizes static vars when they are meet in asm blocks with -O2,-O3,-Os compiler options

[do8896 at db dot com]

------- Additional Comments From do8896 at db dot com  2004-08-16 09:44 -------
Created an attachment (id=6936)
 --> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=6936&action=view)
Compiler and linker logs for -Os options (for -O2 and -O3 result is the same)


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=17047

[Bug c/17047] GCC incorrectly recognizes static vars when they are meet in asm blocks with -O2,-O3,-Os compiler options

[do8896 at db dot com]

------- Additional Comments From do8896 at db dot com  2004-08-16 11:48 -------
Some details:

Failed at:
gcc -funit-at-a-time main.c -o main 

-O2, -O3 and -Os includes -funit-at-a-time


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=17047

[Bug c/17047] GCC incorrectly recognizes static vars when they are meet in asm blocks with -O2,-O3,-Os compiler options

[schwab at suse dot de]

------- Additional Comments From schwab at suse dot de  2004-08-16 13:35 -------
There is no way for gcc to see the reference in the asm.  Either use 
__attribute__((used)) to tell it that the variable is used, or make the 
dependency explicit in the asm by adding it as a parameter. 

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


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=17047

[Bug c/17047] GCC incorrectly recognizes static vars when they are meet in asm blocks with -O2,-O3,-Os compiler options

[schwab at suse dot de]

------- Additional Comments From schwab at suse dot de  2004-08-16 13:39 -------
Duplicate. 

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


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=17047

[Bug c/17047] GCC incorrectly recognizes static vars when they are meet in asm blocks with -O2,-O3,-Os compiler options

[schwab at suse dot de]

------- Additional Comments From schwab at suse dot de  2004-08-16 13:40 -------


*** This bug has been marked as a duplicate of 16551 ***

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


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=17047