On Wed, Jan 28, 2015 at 5:03 PM, Uros Bizjak <ubiz...@gmail.com> wrote:
> Hello!
>
>> Currently ix86_conditional_register_usage code may mark EBX as a fixed
>> register if it is called
>> when pic_offset_table_rtx is NULL even if we are going to use pseudo PIC
>> register. It already
>> caused some problem in combination with another issue (PR jit/64722). This
>> patch will probably
>> help to avoid problems in the future.
>>
>> BTW if we don't want to support possibility to switch to the fixed PIC
>> register in i386 target then
>> this code may be removed at all.
>
> No, we don't want to switch to fixed PIC register. cpuid asm in
> cpuid.h and cmpxchg8b pattern will break. Please do not bring back the
> dead and remove this code.
Also, if possible, please simplify PIC_OFFSET_TABLE_REGNUM to use
TARGET_USE_PSEUDO_PIC_REG, like:
Index: config/i386/i386.h
===================================================================
--- config/i386/i386.h (revision 220230)
+++ config/i386/i386.h (working copy)
@@ -1256,13 +1256,11 @@
#define REAL_PIC_OFFSET_TABLE_REGNUM (TARGET_64BIT ? R15_REG : BX_REG)
#define PIC_OFFSET_TABLE_REGNUM
\
- ((TARGET_64BIT && (ix86_cmodel == CM_SMALL_PIC \
- || TARGET_PECOFF))
\
- || !flag_pic
\
- ? INVALID_REGNUM \
- : pic_offset_table_rtx \
- ? INVALID_REGNUM \
- : REAL_PIC_OFFSET_TABLE_REGNUM)
+ (TARGET_USE_PSEUDO_PIC_REG \
+ ? (pic_offset_table_rtx \
+ ? INVALID_REGNUM \
+ : REAL_PIC_OFFSET_TABLE_REGNUM) \
+ : INVALID_REGNUM)
#define GOT_SYMBOL_NAME "_GLOBAL_OFFSET_TABLE_"
Uros.
