This patch is about error diagnostic + an ICE for invalid code.
Before the patch, gfortran/f951 showed: ... Error: 'ancestor' device modifier not preceded by 'requires' directive with 'reverse_offload' clause 18 | end block | 1 Error: Expecting END PROGRAM statement at (1) gfortran: internal compiler error: Segmentation fault signal terminated program f951 * The first error is for a user error and fine. * A follow-up error is expected (due to the now dangling '!$omp end target'), but the error location and wording is misleading * And the ICE is plainly wrong. With the patch, there is no ICE and the the second error reads: 16 | !$omp end target Error: Unexpected !$OMP END TARGET statement at (1) The problem was due to nesting '!$omp target' (= same directive), where the outer one was a strictly structured block - and parsing the inner '!$omp target' failed with MATCH_ERROR, which ignored that line - while '!$omp end target' remained. (So far, so good, but then the parsing-code did run into a bug.) For the blocks, the following applies. OpenMP permits either * strictly structured blocks (with optional END_ST == 'end target') !$omp target block ... end block !$omp end target ! << this line is optional * loosely structured block !$omp target ... ! may not start with 'block' (and hence cannot end with 'end block') !$omp end target ! << required The parsing issue is in the following code, which first takes care of the 'strictly': 'end block' + optional 'end target' and then of the 'loosely structured' case with just: 'end target': else if (block_construct && st == ST_END_BLOCK) ... st = next_statement (); if (st == omp_end_st) accept_statement (st); ... else if (st != omp_end_st) { unexpected_statement (st); st = next_statement (); } The fix is to change the second if condition to: else if (st != omp_end_st || (block_construct && st == omp_end_st)) or rather to the following equivalent code: else if (st != omp_end_st || block_construct) OK for mainline and GCC 12?* Tobias *strictly structured blocks were added in r12-4592. ----------------- Siemens Electronic Design Automation GmbH; Anschrift: Arnulfstraße 201, 80634 München; Gesellschaft mit beschränkter Haftung; Geschäftsführer: Thomas Heurung, Frank Thürauf; Sitz der Gesellschaft: München; Registergericht München, HRB 106955
Fortran/OpenMP: Fix strictly structured blocks parsing gcc/fortran/ChangeLog: * parse.cc (parse_omp_structured_block): When parsin strictly structured blocks, issue an error if the end-directive comes before the 'end block'. gcc/testsuite/ChangeLog: * gfortran.dg/gomp/strictly-structured-block-4.f90: New test. gcc/fortran/parse.cc | 2 +- .../gomp/strictly-structured-block-4.f90 | 21 +++++++++++++++++++++ 2 files changed, 22 insertions(+), 1 deletion(-) diff --git a/gcc/fortran/parse.cc b/gcc/fortran/parse.cc index 0b4c596996c..80492c952aa 100644 --- a/gcc/fortran/parse.cc +++ b/gcc/fortran/parse.cc @@ -5709,7 +5709,7 @@ parse_omp_structured_block (gfc_statement omp_st, bool workshare_stmts_only) } return st; } - else if (st != omp_end_st) + else if (st != omp_end_st || block_construct) { unexpected_statement (st); st = next_statement (); diff --git a/gcc/testsuite/gfortran.dg/gomp/strictly-structured-block-4.f90 b/gcc/testsuite/gfortran.dg/gomp/strictly-structured-block-4.f90 new file mode 100644 index 00000000000..66cf0a3925e --- /dev/null +++ b/gcc/testsuite/gfortran.dg/gomp/strictly-structured-block-4.f90 @@ -0,0 +1,21 @@ +! { dg-do compile } +implicit none +integer ::x,z +x = 42 +print '(*(z16:" "))', loc(x) +!$omp target map(x, z) +block + integer :: y + x = 123 + y = 99 + !$omp target device(ancestor:1) map(always,tofrom:x) map(y) ! { dg-error "'ancestor' device modifier not preceded by 'requires' directive with 'reverse_offload' clause" } + print '(*(z16:" "))', loc(x), loc(y) + print * ,x, y + x = -x + y = -y + !$omp end target ! { dg-error "Unexpected ..OMP END TARGET statement" } + z = y +end block + print * ,x !, z +end +