On Thu, Jan 29, 2015 at 9:13 AM, Uros Bizjak <ubiz...@gmail.com> wrote:
>>> 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: Ops, better use the attached patch that exports ix86_use_pseudo_pic_reg. Uros.
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) + (ix86_use_pseudo_pic_reg () \ + ? (pic_offset_table_rtx \ + ? INVALID_REGNUM \ + : REAL_PIC_OFFSET_TABLE_REGNUM) \ + : INVALID_REGNUM) #define GOT_SYMBOL_NAME "_GLOBAL_OFFSET_TABLE_" Index: config/i386/i386-protos.h =================================================================== --- config/i386/i386-protos.h (revision 220230) +++ config/i386/i386-protos.h (working copy) @@ -40,6 +40,8 @@ extern enum calling_abi ix86_cfun_abi (void); extern enum calling_abi ix86_function_type_abi (const_tree); +extern bool ix86_use_pseudo_pic_reg (void); + extern void ix86_reset_previous_fndecl (void); #ifdef RTX_CODE
