Re: [Valgrind-developers] wrong diagnostics off uninitialised value if using incw

[Julian S. <js...@ac...>]

> > ------------------------------------
> >         movl    (%rdi), %eax
> >         orl     $1, %eax
> >         incw    %ax
> >         je      .L17
> > ------------------------------------

Hmm, hang on.  I just dealt with this one 5 days ago.

Firstly, what V version is this with?  What gcc version?  And 
what program were you running on V to get this error?

Anyway, can you try the following (on a 3.2.1 tree):

In VEX/priv/guest-amd64/ghelper.c function
guest_amd64_spechelper find the case for DECW (will be obvious,
near line 1188) and after it add this:

      /*---------------- INCW ----------------*/

      if (isU64(cc_op, AMD64G_CC_OP_INCW) && isU64(cond, AMD64CondZ)) {
         /* 16-bit inc, then Z --> test dst == 0 */
         return unop(Iop_1Uto64,
                     binop(Iop_CmpEQ64, 
                           binop(Iop_Shl64,cc_dep1,mkU8(48)), 
                           mkU64(0)));
      }

Rebuild (make clean ; make ; make install) and try again.  Does
that fix it?

If that doesn't work try instead with AMD64CondNZ and Iop_CmpNE64.

J