[clang] [clang][OpenMP] Add error for large expr in collapse clause (PR #138592)

[Amr Hesham via cfe-commits]

https://github.com/AmrDeveloper updated https://github.com/llvm/llvm-project/pull/138592

>From af3e49f1290c61d5856a5ddf600cfd19ef485e25 Mon Sep 17 00:00:00 2001
From: AmrDeveloper <amr96 at programmer.net>
Date: Mon, 5 May 2025 23:01:02 +0200
Subject: [PATCH 1/3] [clang][OpenMP] Add error for large expr in collapse

---
 clang/docs/ReleaseNotes.rst                      | 2 ++
 clang/include/clang/Basic/DiagnosticSemaKinds.td | 2 ++
 clang/lib/Sema/SemaOpenMP.cpp                    | 7 +++++++
 clang/test/OpenMP/simd_collapse_messages.cpp     | 4 ++++
 4 files changed, 15 insertions(+)

diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst
index 7f68fd877e4e2..6ff63e8ffe012 100644
--- a/clang/docs/ReleaseNotes.rst
+++ b/clang/docs/ReleaseNotes.rst
@@ -510,6 +510,8 @@ Improvements to Clang's diagnostics
 - Several compatibility diagnostics that were incorrectly being grouped under
   ``-Wpre-c++20-compat`` are now part of ``-Wc++20-compat``. (#GH138775)
 
+- An error is now emitted when OpenMP ``collapse`` and ``ordered`` clauses has expression larger than 64 bit.
+
 Improvements to Clang's time-trace
 ----------------------------------
 
diff --git a/clang/include/clang/Basic/DiagnosticSemaKinds.td b/clang/include/clang/Basic/DiagnosticSemaKinds.td
index e1b9ed0647bb9..cf6990ff6f3c1 100644
--- a/clang/include/clang/Basic/DiagnosticSemaKinds.td
+++ b/clang/include/clang/Basic/DiagnosticSemaKinds.td
@@ -11523,6 +11523,8 @@ def note_omp_collapse_ordered_expr : Note<
   "as specified in %select{'collapse'|'ordered'|'collapse' and 'ordered'}0 clause%select{||s}0">;
 def err_omp_negative_expression_in_clause : Error<
   "argument to '%0' clause must be a %select{non-negative|strictly positive}1 integer value">;
+def err_omp_large_expression_in_clause : Error<
+  "argument to '%0' clause cannot have more than 64 bits size">;
 def err_omp_not_integral : Error<
   "expression must have integral or unscoped enumeration "
   "type, not %0">;
diff --git a/clang/lib/Sema/SemaOpenMP.cpp b/clang/lib/Sema/SemaOpenMP.cpp
index 835dba22a858d..52cb5b1fb5d71 100644
--- a/clang/lib/Sema/SemaOpenMP.cpp
+++ b/clang/lib/Sema/SemaOpenMP.cpp
@@ -15901,6 +15901,13 @@ ExprResult SemaOpenMP::VerifyPositiveIntegerConstantInClause(
         << E->getSourceRange();
     return ExprError();
   }
+
+  if (!Result.isRepresentableByInt64()) {
+    Diag(E->getExprLoc(), diag::err_omp_large_expression_in_clause)
+        << getOpenMPClauseNameForDiag(CKind) << E->getSourceRange();
+    return ExprError();
+  }
+
   if (CKind == OMPC_collapse && DSAStack->getAssociatedLoops() == 1)
     DSAStack->setAssociatedLoops(Result.getExtValue());
   else if (CKind == OMPC_ordered)
diff --git a/clang/test/OpenMP/simd_collapse_messages.cpp b/clang/test/OpenMP/simd_collapse_messages.cpp
index 1ce3bef3535ce..135b48eea739a 100644
--- a/clang/test/OpenMP/simd_collapse_messages.cpp
+++ b/clang/test/OpenMP/simd_collapse_messages.cpp
@@ -43,6 +43,10 @@ T tmain(T argc, S **argv) {
   for (int i = ST; i < N; i++) argv[0][i] = argv[0][i] - argv[0][i-ST];
   #pragma omp simd collapse (S) // expected-error {{'S' does not refer to a value}}
   for (int i = ST; i < N; i++) argv[0][i] = argv[0][i] - argv[0][i-ST];
+  #pragma omp for collapse (0xFFFFFFFFFFFFFFFF) // expected-error {{argument to 'collapse' clause cannot have more than 64 bits size}}
+  for (int i = ST; i < N; i++) argv[0][i] = argv[0][i] - argv[0][i-ST];
+  #pragma omp simd collapse (0xFFFFFFFFFFFFFFFF) // expected-error {{argument to 'collapse' clause cannot have more than 64 bits size}}
+  for (int i = ST; i < N; i++) argv[0][i] = argv[0][i] - argv[0][i-ST];
 #if __cplusplus <= 199711L
   // expected-error at +4 2 {{integral constant expression}} expected-note at +4 0+{{constant expression}}
 #else

>From 458a9d8cd4e3f5aaf70356517df17932e2b61224 Mon Sep 17 00:00:00 2001
From: AmrDeveloper <amr96 at programmer.net>
Date: Wed, 7 May 2025 21:50:46 +0200
Subject: [PATCH 2/3] Add more test cases

---
 clang/test/OpenMP/for_collapse_messages.cpp      | 2 ++
 clang/test/OpenMP/for_simd_collapse_messages.cpp | 2 ++
 clang/test/OpenMP/simd_collapse_messages.cpp     | 2 --
 3 files changed, 4 insertions(+), 2 deletions(-)

diff --git a/clang/test/OpenMP/for_collapse_messages.cpp b/clang/test/OpenMP/for_collapse_messages.cpp
index 07630ffaaed95..aacf6cb34724a 100644
--- a/clang/test/OpenMP/for_collapse_messages.cpp
+++ b/clang/test/OpenMP/for_collapse_messages.cpp
@@ -49,6 +49,8 @@ T tmain(T argc, S **argv) {
   for (int i = ST; i < N; i++) argv[0][i] = argv[0][i] - argv[0][i-ST];
   #pragma omp for collapse (S) // expected-error {{'S' does not refer to a value}}
   for (int i = ST; i < N; i++) argv[0][i] = argv[0][i] - argv[0][i-ST];
+  #pragma omp for collapse (0xFFFFFFFFFFFFFFFF) // expected-error {{argument to 'collapse' clause cannot have more than 64 bits size}}
+  for (int i = ST; i < N; i++) argv[0][i] = argv[0][i] - argv[0][i-ST];
 #if __cplusplus <= 199711L
   // expected-error at +4 2 {{integral constant expression}} expected-note at +4 0+{{constant expression}}
 #else
diff --git a/clang/test/OpenMP/for_simd_collapse_messages.cpp b/clang/test/OpenMP/for_simd_collapse_messages.cpp
index d9f8a2d971518..d996e6545c0a9 100644
--- a/clang/test/OpenMP/for_simd_collapse_messages.cpp
+++ b/clang/test/OpenMP/for_simd_collapse_messages.cpp
@@ -43,6 +43,8 @@ T tmain(T argc, S **argv) {
   for (int i = ST; i < N; i++) argv[0][i] = argv[0][i] - argv[0][i-ST];
   #pragma omp for simd collapse (S) // expected-error {{'S' does not refer to a value}}
   for (int i = ST; i < N; i++) argv[0][i] = argv[0][i] - argv[0][i-ST];
+  #pragma omp for simd collapse (0xFFFFFFFFFFFFFFFF) // expected-error {{argument to 'collapse' clause cannot have more than 64 bits size}}
+  for (int i = ST; i < N; i++) argv[0][i] = argv[0][i] - argv[0][i-ST];
 #if __cplusplus <= 199711L
   // expected-error at +4 2 {{integral constant expression}} expected-note at +4 0+{{constant expression}}
 #else
diff --git a/clang/test/OpenMP/simd_collapse_messages.cpp b/clang/test/OpenMP/simd_collapse_messages.cpp
index 135b48eea739a..3ae0a818284e9 100644
--- a/clang/test/OpenMP/simd_collapse_messages.cpp
+++ b/clang/test/OpenMP/simd_collapse_messages.cpp
@@ -43,8 +43,6 @@ T tmain(T argc, S **argv) {
   for (int i = ST; i < N; i++) argv[0][i] = argv[0][i] - argv[0][i-ST];
   #pragma omp simd collapse (S) // expected-error {{'S' does not refer to a value}}
   for (int i = ST; i < N; i++) argv[0][i] = argv[0][i] - argv[0][i-ST];
-  #pragma omp for collapse (0xFFFFFFFFFFFFFFFF) // expected-error {{argument to 'collapse' clause cannot have more than 64 bits size}}
-  for (int i = ST; i < N; i++) argv[0][i] = argv[0][i] - argv[0][i-ST];
   #pragma omp simd collapse (0xFFFFFFFFFFFFFFFF) // expected-error {{argument to 'collapse' clause cannot have more than 64 bits size}}
   for (int i = ST; i < N; i++) argv[0][i] = argv[0][i] - argv[0][i-ST];
 #if __cplusplus <= 199711L

>From dc940a3fb7b686f79b87829f288276486d386612 Mon Sep 17 00:00:00 2001
From: AmrDeveloper <amr96 at programmer.net>
Date: Thu, 8 May 2025 18:30:41 +0200
Subject: [PATCH 3/3] Add test cases for omp ordered

---
 clang/test/OpenMP/for_ordered_clause.cpp     | 3 +++
 clang/test/OpenMP/for_simd_loop_messages.cpp | 3 +++
 2 files changed, 6 insertions(+)

diff --git a/clang/test/OpenMP/for_ordered_clause.cpp b/clang/test/OpenMP/for_ordered_clause.cpp
index d9dbb828f6452..40a219953d7a3 100644
--- a/clang/test/OpenMP/for_ordered_clause.cpp
+++ b/clang/test/OpenMP/for_ordered_clause.cpp
@@ -53,6 +53,9 @@ T tmain(T argc, S **argv) {
 #pragma omp for ordered(S) // expected-error {{'S' does not refer to a value}}
   for (int i = ST; i < N; i++)
     argv[0][i] = argv[0][i] - argv[0][i - ST];
+#pragma omp for ordered (0xFFFFFFFFFFFFFFFF) // expected-error {{argument to 'ordered' clause cannot have more than 64 bits size}}
+  for (int i = ST; i < N; i++)
+    argv[0][i] = argv[0][i] - argv[0][i-ST];
 #if __cplusplus <= 199711L
 // expected-error at +4 2 {{integral constant expression}} expected-note at +4 0+{{constant expression}}
 #else
diff --git a/clang/test/OpenMP/for_simd_loop_messages.cpp b/clang/test/OpenMP/for_simd_loop_messages.cpp
index 74a52f3f5d694..9d6c45614a257 100644
--- a/clang/test/OpenMP/for_simd_loop_messages.cpp
+++ b/clang/test/OpenMP/for_simd_loop_messages.cpp
@@ -735,6 +735,9 @@ void test_ordered() {
 #pragma omp for simd ordered(1)
   for (int i = 0; i < 16; ++i)
     ;
+#pragma omp for simd ordered (0xFFFFFFFFFFFFFFFF) // expected-error {{argument to 'ordered' clause cannot have more than 64 bits size}}
+  for (int i = 0; i < 10; i++)
+    ;
 }
 
 void test_nowait() {