On Tue, Mar 13, 2012 at 8:11 AM, Uros Bizjak <ubiz...@gmail.com> wrote:
>>>> Please try attached patch. It introduces TARGET_TLS_INDIRECT_SEG_REFS
>>>> to block only indirect seg references.
>>
>> There is no regression.
>
> Thanks, committed to mainline SVN with following ChangeLog:
>
> 2012-03-13 Uros Bizjak <ubiz...@gmail.com>
>
> * config/i386/i386.h (TARGET_TLS_INDIRECT_SEG_REFS): New.
> * config/i386/i386.c (ix86_decompose_address): Use
> TARGET_TLS_INDIRECT_SEG_REFS to prevent %fs:(%reg) addresses.
> (legitimize_tls_address): Use TARGET_TLS_INDIRECT_SEG_REFS to load
> thread pointer to a register.
>
> Tested on x86_64-pc-linux-gnu {,-m32}.
>
>> BTW, this x32 TLS IE optimization:
>
> > movq %rax, %fs:(%rdx)
>
> This is just looking for troubles. If we said these addresses are
> invalid, then we shouldn't generate them.
OTOH, we can improve rejection test a bit to reject only non-word
mode registers.
2012-03-13 Uros Bizjak <ubiz...@gmail.com>
* config/i386/i386.c (ix86_decompose_address): Prevent %fs:(%reg)
addresses only when %reg is not in word mode.
Tested on x86_64-pc-linux-gnu {,-m32}, committed.
Uros.
Index: i386.c
===================================================================
--- i386.c (revision 185278)
+++ i386.c (working copy)
@@ -11563,8 +11563,10 @@
return 0;
}
- if (seg != SEG_DEFAULT && (base || index)
- && !TARGET_TLS_INDIRECT_SEG_REFS)
+/* Address override works only on the (%reg) part of %fs:(%reg). */
+ if (seg != SEG_DEFAULT
+ && ((base && GET_MODE (base) != word_mode)
+ || (index && GET_MODE (index) != word_mode)))
return 0;
/* Extract the integral value of scale. */
