[Bug fortran/87994] ICE in match_data_constant, at fortran/decl.c:399

["dominiq at lps dot ens.fr" <gcc-bugzilla at gcc dot gnu dot org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=87994

--- Comment #8 from Dominique d'Humieres <dominiq at lps dot ens.fr> ---
I have instrumented gfortran with the patch in comment 5 and all the tests fail
as with pr87881:

=================================================================
==67715==ERROR: AddressSanitizer: heap-use-after-free on address 0x6170000045d8
at pc 0x0001001565a9 bp 0x7ffeefbfdd30 sp 0x7ffeefbfdd28
READ of size 8 at 0x6170000045d8 thread T0
    #0 0x1001565a8 in simplify_ref_chain(gfc_ref*, int, gfc_expr**) expr.c:1943
    #1 0x10015438e in gfc_simplify_expr(gfc_expr*, int) expr.c:2164
    #2 0x100369eaf in gfc_match_varspec(gfc_expr*, int, bool, bool)
primary.c:2287
    #3 0x1003798ba in gfc_match_rvalue(gfc_expr**) primary.c:3670
    #4 0x1000c2f63 in match_data_constant(gfc_expr**) decl.c:379
    #5 0x1000c4291 in top_val_list(gfc_data*) decl.c:478
    #6 0x1000c4905 in gfc_match_data() decl.c:624
    #7 0x10032fbc7 in match_word(char const*, match (*)(), locus*) parse.c:65
    #8 0x10033d154 in decode_statement() parse.c:468
    #9 0x10033ee0d in next_free() parse.c:1234
    #10 0x10033f7d2 in next_statement() parse.c:1466
    #11 0x100345d67 in parse_spec(gfc_statement) parse.c:3858
    #12 0x10034c892 in parse_progunit(gfc_statement) parse.c:5671
    #13 0x10034ec10 in gfc_parse_file() parse.c:6211
    #14 0x100525304 in gfc_be_parse_file() f95-lang.c:204
    #15 0x1062941c8 in compile_file() toplev.c:455
    #16 0x10629f87c in do_compile() toplev.c:2172
    #17 0x109388807 in toplev::main(int, char**) toplev.c:2307
    #18 0x1097eaf4c in main main.c:39
    #19 0x7fff703f908c in start (libdyld.dylib:x86_64+0x1708c)

0x6170000045d8 is located 728 bytes inside of 736-byte region
[0x617000004300,0x6170000045e0)
freed by thread T0 here:
    #0 0x15948a8e0 in wrap_free.part.0 sanitizer_malloc_mac.inc:121
    #1 0x10012e8e5 in gfc_free_ref_list(gfc_ref*) expr.c:599
    #2 0x10012efdd in free_expr0(gfc_expr*) expr.c:505
    #3 0x10012f3be in gfc_replace_expr(gfc_expr*, gfc_expr*) expr.c:616
    #4 0x1001563b7 in simplify_ref_chain(gfc_ref*, int, gfc_expr**) expr.c:1970
    #5 0x10015438e in gfc_simplify_expr(gfc_expr*, int) expr.c:2164
    #6 0x100369eaf in gfc_match_varspec(gfc_expr*, int, bool, bool)
primary.c:2287
    #7 0x1003798ba in gfc_match_rvalue(gfc_expr**) primary.c:3670
    #8 0x1000c2f63 in match_data_constant(gfc_expr**) decl.c:379
    #9 0x1000c4291 in top_val_list(gfc_data*) decl.c:478
    #10 0x1000c4905 in gfc_match_data() decl.c:624
    #11 0x10032fbc7 in match_word(char const*, match (*)(), locus*) parse.c:65
    #12 0x10033d154 in decode_statement() parse.c:468
    #13 0x10033ee0d in next_free() parse.c:1234
    #14 0x10033f7d2 in next_statement() parse.c:1466
    #15 0x100345d67 in parse_spec(gfc_statement) parse.c:3858
    #16 0x10034c892 in parse_progunit(gfc_statement) parse.c:5671
    #17 0x10034ec10 in gfc_parse_file() parse.c:6211
    #18 0x100525304 in gfc_be_parse_file() f95-lang.c:204
    #19 0x1062941c8 in compile_file() toplev.c:455
    #20 0x10629f87c in do_compile() toplev.c:2172
    #21 0x109388807 in toplev::main(int, char**) toplev.c:2307
    #22 0x1097eaf4c in main main.c:39
    #23 0x7fff703f908c in start (libdyld.dylib:x86_64+0x1708c)

previously allocated by thread T0 here:
    #0 0x159489db3 in wrap_calloc sanitizer_malloc_mac.inc:132
    #1 0x1088a10de in xcalloc xmalloc.c:162
    #2 0x10035b5ae in is_inquiry_ref(char const*, gfc_ref**) primary.c:1964
    #3 0x100368721 in gfc_match_varspec(gfc_expr*, int, bool, bool)
primary.c:2199
    #4 0x1003798ba in gfc_match_rvalue(gfc_expr**) primary.c:3670
    #5 0x1000c2f63 in match_data_constant(gfc_expr**) decl.c:379
    #6 0x1000c4291 in top_val_list(gfc_data*) decl.c:478
    #7 0x1000c4905 in gfc_match_data() decl.c:624
    #8 0x10032fbc7 in match_word(char const*, match (*)(), locus*) parse.c:65
    #9 0x10033d154 in decode_statement() parse.c:468
    #10 0x10033ee0d in next_free() parse.c:1234
    #11 0x10033f7d2 in next_statement() parse.c:1466
    #12 0x100345d67 in parse_spec(gfc_statement) parse.c:3858
    #13 0x10034c892 in parse_progunit(gfc_statement) parse.c:5671
    #14 0x10034ec10 in gfc_parse_file() parse.c:6211
    #15 0x100525304 in gfc_be_parse_file() f95-lang.c:204
    #16 0x1062941c8 in compile_file() toplev.c:455
    #17 0x10629f87c in do_compile() toplev.c:2172
    #18 0x109388807 in toplev::main(int, char**) toplev.c:2307
    #19 0x1097eaf4c in main main.c:39
    #20 0x7fff703f908c in start (libdyld.dylib:x86_64+0x1708c)

SUMMARY: AddressSanitizer: heap-use-after-free expr.c:1943 in
simplify_ref_chain(gfc_ref*, int, gfc_expr**)
Shadow bytes around the buggy address:
  0x1c2e00000860: fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd
  0x1c2e00000870: fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd
  0x1c2e00000880: fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd
  0x1c2e00000890: fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd
  0x1c2e000008a0: fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd
=>0x1c2e000008b0: fd fd fd fd fd fd fd fd fd fd fd[fd]fa fa fa fa
  0x1c2e000008c0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x1c2e000008d0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x1c2e000008e0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x1c2e000008f0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x1c2e00000900: 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
  Shadow gap:              cc
==67715==ABORTING
f951: internal compiler error: Abort trap: 6