[Bug tree-optimization/96522] New: Incorrect with with -O -fno-tree-pta

[trt at alumni dot duke.edu]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96522

            Bug ID: 96522
           Summary: Incorrect with with -O -fno-tree-pta
           Product: gcc
           Version: 10.2.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: tree-optimization
          Assignee: unassigned at gcc dot gnu.org
          Reporter: trt at alumni dot duke.edu
  Target Milestone: ---

Created attachment 49020
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=49020&action=edit
demo of flaw in no-tree-pta

The attached program t.c, when compiled with

# gcc (GCC) 10.2.0
gcc t.c -O -fno-tree-pta

has this output:

I think p is non-NULL
I think p is non-NULL

But it is obvious that p is NULL