[Bug c/23422] New: Sign extension removed even when inline assembly uses variable

["anton at samba dot org" <gcc-bugzilla at gcc dot gnu dot org>]

When using the recent debian 4.0 build (gcc version 4.0.2 20050806 (prerelease)
(Debian 4.0.1-4)) I had some problems with a 64bit kernel.

A cut down test case is:

#define BUG_ON(x) asm volatile("tdnei %0,0" : : "r" (x));

static inline int bar(int val)
{
        return val + 1;
}

int foo;

void baz()
{
        BUG_ON(bar(foo));
}

gcc 3.4 sign extends before passing it to the inline assembly:

.baz:
        ld 11,.LC0@toc(2)
        lwa 9,0(11)
        addi 9,9,1
        extsw 9,9
        tdnei 9,0

But gcc 4.0 has removed the sign extension:

.baz:
        ld 11,.LC0@toc(2)
        lwz 9,0(11)
        addi 9,9,1
        tdnei 9,0

gcc 4.0 does get it right with -fno-inline.

-- 
           Summary: Sign extension removed even when inline assembly uses
                    variable
           Product: gcc
           Version: 4.0.2
            Status: UNCONFIRMED
          Severity: normal
          Priority: P2
         Component: c
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: anton at samba dot org
                CC: gcc-bugs at gcc dot gnu dot org
GCC target triplet: powerpc64-unknown-linux-gnu


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=23422