[Clang][OpenMP] Fixing Clang error for metadirective with multiple when clauses and no otherwise

[Ritanya-B-Bharadwaj]

Fixing - #147336

[llvmbot]

@llvm/pr-subscribers-clang

Author: None (Ritanya-B-Bharadwaj)

Changes

Fixing - #147336

---

Full diff: https://github.com/llvm/llvm-project/pull/148583.diff

1 Files Affected:

• (modified) clang/lib/Parse/ParseOpenMP.cpp (+1-1)

diff --git a/clang/lib/Parse/ParseOpenMP.cpp b/clang/lib/Parse/ParseOpenMP.cpp
index aa6a0c61a2c17..5db2f2e2ccf86 100644
--- a/clang/lib/Parse/ParseOpenMP.cpp
+++ b/clang/lib/Parse/ParseOpenMP.cpp
@@ -2704,7 +2704,7 @@ StmtResult Parser::ParseOpenMPDeclarativeOrExecutableDirective(
     // If no match is found and no otherwise clause is present, skip
     // OMP5.2 Chapter 7.4: If no otherwise clause is specified the effect is as
     // if one was specified without an associated directive variant.
-    if (BestIdx == -1 && Idx == 1) {
+    if (BestIdx == -1 && Idx > 0) {
       assert(Tok.is(tok::annot_pragma_openmp_end) &&
              "Expecting the end of the pragma here");
       ConsumeAnnotationToken();

[zahiraam]

You need to add a LIT test.

[Ritanya-B-Bharadwaj]

You need to add a LIT test.

Done!

[zahiraam]

The LIT test is passing even without your change above. It needs a bit more work. Furthermore your patch doesn't seem to be enough. The reproducer in #147336 is still failing with your patch.

[Ritanya-B-Bharadwaj]

I have changed the lit test case. The reproducer passes with this patch.

[zahiraam]

I would suggest adding this:
#pragma omp metadirective when(user = {condition(0)} \
: parallel for) when(user = {condition(0)} \
: target teams distribute parallel for)
for (int i = 0; i < 100; i++)
;

to OpenMP/metadirective_otherwise.cpp instead. You will need to edit the IR generated.

[Ritanya-B-Bharadwaj]

Since there's no IR change involved and the bug occurs during parsing, I think it's appropriate to keep the test in the messages lit test.
Also the issue being fixed here affects metadirectives that use non-constant conditions, like condition(x), where x is a variable or identifier. It doesn't occur with simple constants like condition(0) or condition(1).