[Bug c/103447] New: left shift operator gives wrong result for shift of 48

[Bug c/103447] New: left shift operator gives wrong result for shift of 48

[pgmer6809 at yahoo dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103447

            Bug ID: 103447
           Summary: left shift operator gives wrong result for shift of 48
           Product: gcc
           Version: 9.3.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c
          Assignee: unassigned at gcc dot gnu.org
          Reporter: pgmer6809 at yahoo dot com
  Target Milestone: ---

Created attachment 51886
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=51886&action=edit
results of the gcc -v save-temps

GCC cannot handle  the statement:

unsigned long long int two48 = 1<<48

on a 64 bit machine with sizeof (two48) = 8.

However it can handle the following fragment:

unsigned long long int two16, two48;
two16 =  256 * 256;
two48=two16*two16*two16 ;

See below
I wanted to attach all the files but I can only attach one.
You said not to make archive or zip files so there it is. No .s or .i file

[Bug c/103447] left shift operator gives wrong result for shift of 48

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103447

Andrew Pinski <pinskia at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |RESOLVED
         Resolution|---                         |INVALID

--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Use 1ll<<48 to get the right value. 1 by itself is of type int which is 32 bit
so you are shifting outside of the bounds and there for it is undefined.

[Bug c/103447] left shift operator gives wrong result for shift of 48

[pgmer6809 at yahoo dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103447

--- Comment #2 from Greg Morse <pgmer6809 at yahoo dot com> ---
 Thanks for the  v. quick reply. I feel like an idiot.G. M. 

    On Friday, November 26, 2021, 04:13:45 p.m. PST, pinskia at gcc dot gnu.org
<gcc-bugzilla@gcc.gnu.org> wrote:  

 https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103447

Andrew Pinski <pinskia at gcc dot gnu.org> changed:

          What    |Removed                    |Added
----------------------------------------------------------------------------
            Status|UNCONFIRMED                |RESOLVED
        Resolution|---                        |INVALID

--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Use 1ll<<48 to get the right value. 1 by itself is of type int which is 32 bit
so you are shifting outside of the bounds and there for it is undefined.