[Bug c++/108407] SegFault with structured binding and OpenMP without optimization

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108407

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

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

--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
With -fsanitize=undefined,address we get:

=================================================================
==1==ERROR: AddressSanitizer: stack-use-after-return on address 0x7ff991800030
at pc 0x0000004016c4 bp 0x7ffd675ea150 sp 0x7ffd675ea148
READ of size 4 at 0x7ff991800030 thread T0
    #0 0x4016c3 in main /app/example.cpp:19
    #1 0x7ff993d50082 in __libc_start_main
(/lib/x86_64-linux-gnu/libc.so.6+0x24082) (BuildId:
1878e6b475720c7c51969e69ab2d276fae6d1dee)
    #2 0x40115d in _start (/app/output.s+0x40115d) (BuildId:
c6fef22ac59389c6ed0248b91200737f3dfa67d0)

Address 0x7ff991800030 is located in stack of thread T0 at offset 48 in frame
    #0 0x401225 in create() /app/example.cpp:7

  This frame has 2 object(s):
    [48, 52) 'a' (line 8) <== Memory access at offset 48 is inside this
variable
    [64, 72) 'b' (line 9)
HINT: this may be a false positive if your program uses some custom stack
unwind mechanism, swapcontext or vfork
      (longjmp and C++ exceptions *are* supported)
SUMMARY: AddressSanitizer: stack-use-after-return /app/example.cpp:19 in main
Shadow bytes around the buggy address:
  0x7ff9917ffd80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x7ff9917ffe00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x7ff9917ffe80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x7ff9917fff00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x7ff9917fff80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
=>0x7ff991800000: f5 f5 f5 f5 f5 f5[f5]f5 f5 f5 f5 f5 00 00 00 00
  0x7ff991800080: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x7ff991800100: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x7ff991800180: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x7ff991800200: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x7ff991800280: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
Shadow byte legend (one shadow byte represents 8 application bytes):
  Addressable:           00
  Partially addressable: 01 02 03 04 05 06 07 
  Heap left redzone:       fa
  Freed heap region:       fd
  Stack left redzone:      f1
  Stack mid redzone:       f2
  Stack right redzone:     f3
  Stack after return:      f5
  Stack use after scope:   f8
  Global redzone:          f9
  Global init order:       f6
  Poisoned by user:        f7
  Container overflow:      fc
  Array cookie:            ac
  Intra object redzone:    bb
  ASan internal:           fe
  Left alloca redzone:     ca
  Right alloca redzone:    cb
==1==ABORTING