[flang-commits] [flang] c2e41be - [flang][Parser] Add whitespace token after the sentinel in fixed form (#148825)

[via flang-commits]

Author: Tom Eccles
Date: 2025-07-15T16:39:34+01:00
New Revision: c2e41be50f2cc3d1e99c30b1996b8873b05c4b0e

URL: https://github.com/llvm/llvm-project/commit/c2e41be50f2cc3d1e99c30b1996b8873b05c4b0e
DIFF: https://github.com/llvm/llvm-project/commit/c2e41be50f2cc3d1e99c30b1996b8873b05c4b0e.diff

LOG: [flang][Parser] Add whitespace token after the sentinel in fixed form (#148825)

Fixes #148386

The first time the line was classified (using
`Prescanner::ClassifyLine(const char *)`) the line was correctly
classified as a compiler directive. But then later on the token form is
invoked (`Prescanner::ClassifyLine(TokenSequence, Provenance)`). This
one incorrectly classified the line as a comment because there was no
whitespace token right after the sentinel. This fixes the issue by
ensuring this whitespace is added.

Added: 
    flang/test/Preprocessing/omp-sentinel-fixed-form.F

Modified: 
    flang/lib/Parser/prescan.cpp

Removed: 
    


################################################################################
diff  --git a/flang/lib/Parser/prescan.cpp b/flang/lib/Parser/prescan.cpp
index ec894ab8513d2..3a9a475c365ee 100644
--- a/flang/lib/Parser/prescan.cpp
+++ b/flang/lib/Parser/prescan.cpp
@@ -179,7 +179,9 @@ void Prescanner::Statement() {
         EmitChar(tokens, *sp);
       }
       if (inFixedForm_) {
-        while (column_ < 6) {
+        // We need to add the whitespace after the sentinel because otherwise
+        // the line cannot be re-categorised as a compiler directive.
+        while (column_ <= 6) {
           if (*at_ == '\t') {
             tabInCurrentLine_ = true;
             ++at_;

diff  --git a/flang/test/Preprocessing/omp-sentinel-fixed-form.F b/flang/test/Preprocessing/omp-sentinel-fixed-form.F
new file mode 100644
index 0000000000000..c8271682a5b92
--- /dev/null
+++ b/flang/test/Preprocessing/omp-sentinel-fixed-form.F
@@ -0,0 +1,21 @@
+! RUN: %flang_fc1 -fdebug-unparse -fopenmp -fopenmp-version=50 %s | FileCheck %s
+
+#define OMP_TARGET        .true.
+#define OMP_SIMD    .false.
+      program test
+      implicit none
+      integer     i,j,n
+      n = 100
+! CHECK: !$OMP METADIRECTIVE  WHEN(USER={CONDITION(.true._4)}: TARGET TEAMS DISTRIBUTE PARALLEL&
+! CHECK: !$OMP& DO) DEFAULT(TARGET TEAMS LOOP)
+!$omp  metadirective
+!$omp& when(user={condition(OMP_TARGET.or.OMP_SIMD)}:
+!$omp&      target teams distribute parallel do )
+!$omp& default(target teams loop)
+      do i=0,n
+        do j=0,n
+          write(*,*) "Test"
+        enddo
+      enddo
+      return
+      end program