[Bug target/100236] arm: UB in arm_compute_save_core_reg_mask (shift exponent 4294967295 is too large for 32-bit type 'int')

[rearnsha at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100236

Richard Earnshaw <rearnsha at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
     Ever confirmed|0                           |1
   Last reconfirmed|                            |2021-04-26
             Status|UNCONFIRMED                 |NEW

--- Comment #2 from Richard Earnshaw <rearnsha at gcc dot gnu.org> ---
Confirmed.  The macro THUMB2_WORK_REGS expands to

(0xff & ~(  (1 << THUMB_HARD_FRAME_POINTER_REGNUM) \
                                   | (1 << SP_REGNUM) | (1 << PC_REGNUM) \
                                   | (1 << PIC_OFFSET_TABLE_REGNUM)))

But PIC_OFFSET_TABLE_REGNUM in turn expands to

arm_pic_register

which may be INVALID_REGNUM (~0) in some circumstances.