On Fri, Mar 18, 2011 at 2:03 PM, Richard Henderson <r...@redhat.com> wrote: > On 03/17/2011 03:28 PM, H.J. Lu wrote: >> It will require very extensive changes to x86 backend since stack pointer >> and frame pointer are really in DImode for x32 as x32 process runs in >> 64bit mode. If you can make it to work, please let me know. > > Yes, the stack pointer uses all 64 bits for e.g. push/pop/call. But so > what? Given that our 32-bit move insns also implicitly zero-extend, I > don't see that we need to actually expose the fact of the 64-bit RSP to > the rest of the compiler. >
X86 backend uses Pmode for hardware pointer size. Changes it to 32bit for x32, which is really 64bit process, breaks many assumptions of x86 backend. push/pop/call is just the tip of the iceberg. -- H.J.
