https://github.com/zahiraam created 
https://github.com/llvm/llvm-project/pull/224019

None

>From b925b2c3fa0f15b20898bd6456329eddfdb027ea Mon Sep 17 00:00:00 2001
From: Zahira Ammarguellat <[email protected]>
Date: Wed, 20 May 2026 05:48:13 -0700
Subject: [PATCH 1/2] [OpenMP] Prevent parser infinite loop on unimplemented
 clauses

---
 clang/lib/Basic/OpenMPKinds.cpp               |  1 +
 clang/lib/Parse/ParseOpenMP.cpp               |  9 ++
 clang/lib/Sema/SemaOpenMP.cpp                 |  4 +
 .../OpenMP/unimplemented_clause_messages.cpp  | 93 +++++++++++++++++++
 4 files changed, 107 insertions(+)
 create mode 100644 clang/test/OpenMP/unimplemented_clause_messages.cpp

diff --git a/clang/lib/Basic/OpenMPKinds.cpp b/clang/lib/Basic/OpenMPKinds.cpp
index 287eb217ba458..675d86349c933 100644
--- a/clang/lib/Basic/OpenMPKinds.cpp
+++ b/clang/lib/Basic/OpenMPKinds.cpp
@@ -965,6 +965,7 @@ void clang::getOpenMPCaptureRegions(
     case OMPD_simd:
     case OMPD_single:
     case OMPD_target_data:
+    case OMPD_taskgraph:
     case OMPD_taskgroup:
     case OMPD_stripe:
       // These directives (when standalone) use OMPD_unknown as the region,
diff --git a/clang/lib/Parse/ParseOpenMP.cpp b/clang/lib/Parse/ParseOpenMP.cpp
index 45a47ec797f01..ba3d3113700ff 100644
--- a/clang/lib/Parse/ParseOpenMP.cpp
+++ b/clang/lib/Parse/ParseOpenMP.cpp
@@ -2388,6 +2388,8 @@ StmtResult Parser::ParseOpenMPExecutableDirective(
     ImplicitClauseAllowed = false;
     Actions.OpenMP().StartOpenMPClause(CKind);
     HasImplicitClause = false;
+    SourceLocation ClauseLoc = Tok.getLocation();
+
     OMPClause *Clause =
         ParseOpenMPClause(DKind, CKind, !SeenClauses[unsigned(CKind)]);
     SeenClauses[unsigned(CKind)] = true;
@@ -2398,6 +2400,13 @@ StmtResult Parser::ParseOpenMPExecutableDirective(
     if (Tok.is(tok::comma))
       ConsumeToken();
     Actions.OpenMP().EndOpenMPClause();
+
+    // If ParseOpenMPClause returned without consuming any tokens, skip
+    // to end to avoid an infinite loop.
+    if (Tok.getLocation() == ClauseLoc) {
+      skipUntilPragmaOpenMPEnd(DKind);
+      break;
+    }
   }
   // End location of the directive.
   EndLoc = Tok.getLocation();
diff --git a/clang/lib/Sema/SemaOpenMP.cpp b/clang/lib/Sema/SemaOpenMP.cpp
index d6f6bc919a31b..76b40a5039180 100644
--- a/clang/lib/Sema/SemaOpenMP.cpp
+++ b/clang/lib/Sema/SemaOpenMP.cpp
@@ -6778,6 +6778,10 @@ StmtResult SemaOpenMP::ActOnOpenMPExecutableDirective(
   case OMPD_begin_declare_variant:
   case OMPD_end_declare_variant:
     llvm_unreachable("OpenMP Directive is not allowed");
+  case OMPD_taskgraph:
+    Diag(StartLoc, diag::err_omp_unexpected_directive)
+        << 1 << getOpenMPDirectiveName(OMPD_taskgraph);
+    return StmtError();
   case OMPD_unknown:
   default:
     llvm_unreachable("Unknown OpenMP directive");
diff --git a/clang/test/OpenMP/unimplemented_clause_messages.cpp 
b/clang/test/OpenMP/unimplemented_clause_messages.cpp
new file mode 100644
index 0000000000000..172203ea5d040
--- /dev/null
+++ b/clang/test/OpenMP/unimplemented_clause_messages.cpp
@@ -0,0 +1,93 @@
+// RUN: %clang_cc1 -verify=expected,omp60 -fopenmp -fopenmp-version=60 %s
+// RUN: %clang_cc1 -verify=expected,omp51 -fopenmp -fopenmp-version=51 %s
+// RUN: %clang_cc1 -verify=expected,omp60 -fopenmp-simd -fopenmp-version=60 %s
+// RUN: %clang_cc1 -verify=expected,omp51 -fopenmp-simd -fopenmp-version=51 %s
+
+
+void test_induction_basic() {
+  int i;
+  // omp60-warning@+4{{extra tokens at the end of '#pragma omp parallel for' 
are ignored}}
+  // omp60-error@+3{{unexpected OpenMP clause 'induction' in directive 
'#pragma omp parallel for'}}
+  // omp51-warning@+2{{extra tokens at the end of '#pragma omp parallel for' 
are ignored}}
+  // omp51-error@+1{{unexpected OpenMP clause 'induction' in directive 
'#pragma omp parallel for'}}
+#pragma omp parallel for induction(i)
+  for (i = 0; i < 10; ++i)
+    ;
+}
+
+void test_apply() {
+  // omp60-warning@+4{{extra tokens at the end of '#pragma omp tile' are 
ignored}}
+  // omp60-error@+3{{unexpected OpenMP clause 'apply' in directive '#pragma 
omp tile'}}
+  // omp51-error@+2{{unexpected OpenMP clause 'apply' in directive '#pragma 
omp tile'}}
+  // omp51-warning@+1{{extra tokens at the end of '#pragma omp tile' are 
ignored}}
+#pragma omp tile sizes(10) apply(intratile: unroll)
+  for (int i = 0; i < 10; ++i)
+    ;
+}
+
+void test_empty_apply() {
+ // omp60-warning@+4{{extra tokens at the end of '#pragma omp tile' are 
ignored}}
+  // omp60-error@+3{{unexpected OpenMP clause 'apply' in directive '#pragma 
omp tile'}}
+  // omp51-error@+2{{unexpected OpenMP clause 'apply' in directive '#pragma 
omp tile'}}
+  // omp51-warning@+1{{extra tokens at the end of '#pragma omp tile' are 
ignored}}
+#pragma omp tile sizes(10) apply()
+  for (int i = 0; i < 10; ++i)
+    ;
+}
+
+void test_nested_apply()
+{
+  // omp60-error@+5{{unexpected OpenMP clause 'apply' in directive '#pragma 
omp tile'}}
+  // omp60-warning@+4{{extra tokens at the end of '#pragma omp tile' are 
ignored}}
+  //omp51-error@+3{{unexpected OpenMP clause 'apply' in directive '#pragma omp 
tile'}}
+  // omp51-warning@+2{{extra tokens at the end of '#pragma omp tile' are 
ignored}}
+#pragma omp tile sizes(10) \
+            apply(intratile: unroll partial(2) apply(reverse))
+  for (int i = 0; i < 100; ++i)
+    ;
+}
+
+void test_induction_with_following_clause() {
+  int i;
+  // omp60-warning@+4{{extra tokens at the end of '#pragma omp parallel for' 
are ignored}}
+  // omp60-error@+3{{unexpected OpenMP clause 'induction' in directive 
'#pragma omp parallel for'}}
+  // omp51-error@+2{{unexpected OpenMP clause 'induction' in directive 
'#pragma omp parallel for'}}
+  // omp51-warning@+1{{extra tokens at the end of '#pragma omp parallel for' 
are ignored}}
+#pragma omp parallel for induction(i) num_threads(4)
+  for (i = 0; i < 10; ++i)
+    ;
+}
+
+class Point {
+  float x, y, m;
+  char color;
+
+};
+
+void processPointsInLine() {
+  float separation;
+  // omp60-error@+4{{unexpected OpenMP clause 'induction' in directive 
'#pragma omp parallel for'}}
+  // omp60-warning@+3{{extra tokens at the end of '#pragma omp parallel for' 
are ignored}}
+  // omp51-error@+2{{unexpected OpenMP clause 'induction' in directive 
'#pragma omp parallel for'}}
+  // omp51-warning@+1{{extra tokens at the end of '#pragma omp parallel for' 
are ignored}}
+#pragma omp parallel for induction(step(Separation))
+  for (int i = 0; i < 10; ++i) {
+    ;
+  }
+}
+
+// Make sure test doesn't crash.
+void test_tasgraph()
+{
+  // omp60-error@+2{{unexpected OpenMP directive '#pragma omp taskgraph'}}
+  // omp51-error@+1{{unexpected OpenMP directive '#pragma omp taskgraph'}}
+#pragma omp taskgraph
+  for (int i = 0; i < 10; ++i)
+    ;
+}
+
+void test_implemented_clause() {
+#pragma omp tile sizes(10)
+  for (int i = 0; i < 10; ++i)
+    ;
+}

>From a17d08bb350951da18541f0106e35bc726e6de39 Mon Sep 17 00:00:00 2001
From: Zahira Ammarguellat <[email protected]>
Date: Wed, 16 Sep 2026 06:49:13 -0700
Subject: [PATCH 2/2] [Clang][C23] Fix typedef-name after 'auto' as
 storage-class use

---
 clang/lib/Parse/ParseDecl.cpp | 31 +++++++++++++++++++++++++++++++
 clang/test/C/C23/n3007.c      | 18 ++++++++++++++++++
 2 files changed, 49 insertions(+)

diff --git a/clang/lib/Parse/ParseDecl.cpp b/clang/lib/Parse/ParseDecl.cpp
index 9fa3b96527c08..b1160063161b9 100644
--- a/clang/lib/Parse/ParseDecl.cpp
+++ b/clang/lib/Parse/ParseDecl.cpp
@@ -4147,6 +4147,27 @@ void Parser::ParseDeclarationSpecifiers(
       break;
     case tok::kw_auto:
       if (getLangOpts().CPlusPlus11 || getLangOpts().C23) {
+        // FIXME: In C++, `auto` as a storage-class specifier is a
+        // deprecated extension. This lookahead runs for C only; teaching it
+        // to also recognize typedef-names in C++ would require broader
+        // design discussion around `ext_auto_storage_class`. See
+        // https://github.com/llvm/llvm-project/issues/164930.
+        auto IsTypedefName = [&](const Token &T) {
+          if (!T.is(tok::identifier))
+            return false;
+          IdentifierInfo *II = T.getIdentifierInfo();
+          if (!II)
+            return false;
+          // Use a raw suppressed lookup (rather than Sema::getTypeName) to
+          // avoid emitting deprecation/availability diagnostics on the
+          // typedef during this speculative peek — the real parse will look
+          // the name up again and emit them at the right time.
+          LookupResult R(Actions, II, T.getLocation(), 
Sema::LookupOrdinaryName);
+          Actions.LookupName(R, getCurScope(),
+                             /*AllowBuiltinCreation=*/false);
+          R.suppressDiagnostics();
+          return R.isSingleResult() && isa<TypeDecl>(R.getFoundDecl());
+        };
         auto MayBeTypeSpecifier = [&]() {
           // In pre-C23 C, auto can be used as a storage-class specifier.
           // C23 removes auto from the storage-class specifiers and repurposes
@@ -4161,6 +4182,16 @@ void Parser::ParseDeclarationSpecifiers(
             if (isKnownToBeTypeSpecifier(T))
               return true;
 
+            // C23: a bare identifier that names a typedef is a type
+            // specifier here, so `auto typedefName varName;` should be
+            // parsed with `auto` as the storage-class specifier — not as
+            // type inference. Without this check the parser would consume
+            // `auto` as type-inference and then error on the missing
+            // initializer for what it thinks is `typedefName` (issue
+            // #164930).
+            if (getLangOpts().C23 && IsTypedefName(T))
+              return true;
+
             if (getLangOpts().C23 && isTypeSpecifierQualifier(T))
               ++I;
             else
diff --git a/clang/test/C/C23/n3007.c b/clang/test/C/C23/n3007.c
index a881b89443462..143a2fcc6796e 100644
--- a/clang/test/C/C23/n3007.c
+++ b/clang/test/C/C23/n3007.c
@@ -209,3 +209,21 @@ void test_macros(int in_int) {
   _Static_assert(_Generic(c, int : 1));
   _Static_assert(_Generic(result, int : 1));
 }
+
+// Regression test for #164930: `auto <typedef-name> <var>;` should parse as a
+// declaration of <var> with type <typedef-name> (auto used as storage-class in
+// C23 with an explicit type-name), not as inferred type deduction on the
+// typedef.
+void test_auto_typedef(void) {
+  typedef int T;
+  {
+    auto T at_local;
+    at_local = 42;
+    _Static_assert(_Generic(at_local, int : 1));
+  }
+  {
+    // Also works with qualifiers.
+    const auto T at_const = 1;
+    _Static_assert(_Generic(&at_const, const int * : 1));
+  }
+}

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