[Bug c++/99072] [modules] Compiling header unit with partial preprocessing (-E -fdirectives-only) twice causes CRC mismatch

[nathan at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99072

Nathan Sidwell <nathan at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Last reconfirmed|                            |2021-02-16
             Status|UNCONFIRMED                 |WAITING
     Ever confirmed|0                           |1

--- Comment #1 from Nathan Sidwell <nathan at gcc dot gnu.org> ---
cannot reproduce:

3 first build of header-unit
devvm1702:41>./xg++ -B./ -nostdinc++
-I../x86_64-pc-linux-gnu/libstdc++-v3/include/x86_64-pc-linux-gnu
-I../x86_64-pc-linux-gnu/libstdc++-v3/include
-I../../..//src/libstdc++-v3/libsupc++
-I../../../src/libstdc++-v3/include/backward
-I../../../src/libstdc++-v3/testsuite/util -std=c++2a -fmodule-header -E
-fdirectives-only -o 99072_a.ii 99072_a.H
devvm1702:42>./xg++ -B./ -nostdinc++
-I../x86_64-pc-linux-gnu/libstdc++-v3/include/x86_64-pc-linux-gnu
-I../x86_64-pc-linux-gnu/libstdc++-v3/include
-I../../..//src/libstdc++-v3/libsupc++
-I../../../src/libstdc++-v3/include/backward
-I../../../src/libstdc++-v3/testsuite/util -std=c++2a -fmodule-header
-fpreprocessed -fdirectives-only -c 99072_a.ii

# build module 'hello'
devvm1702:43>./xg++ -B./ -nostdinc++
-I../x86_64-pc-linux-gnu/libstdc++-v3/include/x86_64-pc-linux-gnu
-I../x86_64-pc-linux-gnu/libstdc++-v3/include
-I../../..//src/libstdc++-v3/libsupc++
-I../../../src/libstdc++-v3/include/backward
-I../../../src/libstdc++-v3/testsuite/util -std=c++2a -fmodules-ts -c 99072_b.C 

# save header-unit cmi
devvm1702:44>cp gcm.cache/,/99072_a.H.gcm .

# second build of string
devvm1702:45>./xg++ -B./ -nostdinc++
-I../x86_64-pc-linux-gnu/libstdc++-v3/include/x86_64-pc-linux-gnu
-I../x86_64-pc-linux-gnu/libstdc++-v3/include
-I../../..//src/libstdc++-v3/libsupc++
-I../../../src/libstdc++-v3/include/backward
-I../../../src/libstdc++-v3/testsuite/util -std=c++2a -fmodule-header -E
-fdirectives-only -o 99072_a.ii 99072_a.H
devvm1702:46>./xg++ -B./ -nostdinc++
-I../x86_64-pc-linux-gnu/libstdc++-v3/include/x86_64-pc-linux-gnu
-I../x86_64-pc-linux-gnu/libstdc++-v3/include
-I../../..//src/libstdc++-v3/libsupc++
-I../../../src/libstdc++-v3/include/backward
-I../../../src/libstdc++-v3/testsuite/util -std=c++2a -fmodule-header
-fpreprocessed -fdirectives-only -c 99072_a.ii

# build main
devvm1702:47>./xg++ -B./ -nostdinc++
-I../x86_64-pc-linux-gnu/libstdc++-v3/include/x86_64-pc-linux-gnu
-I../x86_64-pc-linux-gnu/libstdc++-v3/include
-I../../..//src/libstdc++-v3/libsupc++
-I../../../src/libstdc++-v3/include/backward
-I../../../src/libstdc++-v3/testsuite/util -std=c++2a -fmodules-ts -c 99072_c.C

# no error