[clang] [OpenMP] Fix calculation of dependencies for multi-dimensional iteration space (PR #99347)

[via cfe-commits]

https://github.com/jprotze updated https://github.com/llvm/llvm-project/pull/99347

>From b45379e5317a00b91e514d89424da69c631ca514 Mon Sep 17 00:00:00 2001
From: Joachim Jenke <jenke at itc.rwth-aachen.de>
Date: Wed, 17 Jul 2024 17:08:59 +0200
Subject: [PATCH] Fix calculation of dependencies for multi-dimensional
 iteration space

---
 clang/lib/CodeGen/CGOpenMPRuntime.cpp   | 13 +++++++----
 clang/test/OpenMP/depend_iterator_bug.c | 29 +++++++++++++++++++++++++
 clang/test/OpenMP/task_codegen.c        |  3 ++-
 3 files changed, 40 insertions(+), 5 deletions(-)

diff --git a/clang/lib/CodeGen/CGOpenMPRuntime.cpp b/clang/lib/CodeGen/CGOpenMPRuntime.cpp
index 652fb700fc6af..541c2504bb73b 100644
--- a/clang/lib/CodeGen/CGOpenMPRuntime.cpp
+++ b/clang/lib/CodeGen/CGOpenMPRuntime.cpp
@@ -4259,14 +4259,19 @@ std::pair<llvm::Value *, Address> CGOpenMPRuntime::emitDependClause(
     // Include number of iterations, if any.
 
     if (const auto *IE = cast_or_null<OMPIteratorExpr>(D.IteratorExpr)) {
+      llvm::Value *ClauseIteratorSpace =
+          llvm::ConstantInt::get(CGF.IntPtrTy, 1);
       for (unsigned I = 0, E = IE->numOfIterators(); I < E; ++I) {
         llvm::Value *Sz = CGF.EmitScalarExpr(IE->getHelper(I).Upper);
         Sz = CGF.Builder.CreateIntCast(Sz, CGF.IntPtrTy, /*isSigned=*/false);
-        llvm::Value *NumClauseDeps = CGF.Builder.CreateNUWMul(
-            Sz, llvm::ConstantInt::get(CGF.IntPtrTy, D.DepExprs.size()));
-        NumOfRegularWithIterators =
-            CGF.Builder.CreateNUWAdd(NumOfRegularWithIterators, NumClauseDeps);
+        ClauseIteratorSpace = CGF.Builder.CreateNUWMul(Sz, ClauseIteratorSpace);
       }
+      llvm::Value *NumClauseDeps =
+          CGF.Builder.CreateNUWMul(
+          ClauseIteratorSpace, 
+          llvm::ConstantInt::get(CGF.IntPtrTy, D.DepExprs.size()));
+      NumOfRegularWithIterators =
+          CGF.Builder.CreateNUWAdd(NumOfRegularWithIterators, NumClauseDeps);
       HasRegularWithIterators = true;
       continue;
     }
diff --git a/clang/test/OpenMP/depend_iterator_bug.c b/clang/test/OpenMP/depend_iterator_bug.c
index b4aaaac08374f..ff11d8a5d0e40 100644
--- a/clang/test/OpenMP/depend_iterator_bug.c
+++ b/clang/test/OpenMP/depend_iterator_bug.c
@@ -5,6 +5,7 @@
 
 int x[100];
 int y[100];
+int z[100][100];
 
 // CHECK-LABEL: @many_iterators_single_clause(
 // CHECK:    [[VLA:%.*]] = alloca [[STRUCT_KMP_DEPEND_INFO:%.*]], i64 10, align 16
@@ -24,3 +25,31 @@ void many_iterators_many_clauses(void) {
     {
     }
 }
+
+// CHECK-LABEL: @multidim_iterators_clause1(
+// CHECK:    [[VLA:%.*]] = alloca [[STRUCT_KMP_DEPEND_INFO:%.*]], i64 1, align 16
+// CHECK:    = call i32 @__kmpc_omp_task_with_deps(ptr {{.*}}, i32 {{.*}}, ptr {{.*}}, i32 1, ptr {{.*}}, i32 0, ptr null)
+void multidim_iterators_clause1(void) {
+    #pragma omp task depend(iterator(i=0:1, j=0:1), in: z[i][j])
+    {
+    }
+}
+
+// CHECK-LABEL: @multidim_iterators_offset_clause(
+// CHECK:    [[VLA:%.*]] = alloca [[STRUCT_KMP_DEPEND_INFO:%.*]], i64 1, align 16
+// CHECK:    = call i32 @__kmpc_omp_task_with_deps(ptr {{.*}}, i32 {{.*}}, ptr {{.*}}, i32 1, ptr {{.*}}, i32 0, ptr null)
+void multidim_iterators_offset_clause(void) {
+    #pragma omp task depend(iterator(i=5:6, j=10:11), in: z[i][j])
+    {
+    }
+}
+
+// CHECK-LABEL: @multidim_iterators_clause25(
+// CHECK:    [[VLA:%.*]] = alloca [[STRUCT_KMP_DEPEND_INFO:%.*]], i64 25, align 16
+// CHECK:    = call i32 @__kmpc_omp_task_with_deps(ptr {{.*}}, i32 {{.*}}, ptr {{.*}}, i32 25, ptr {{.*}}, i32 0, ptr null)
+void multidim_iterators_clause25(void) {
+    #pragma omp task depend(iterator(i=0:5, j=0:5), in: z[i][j])
+    {
+    }
+}
+
diff --git a/clang/test/OpenMP/task_codegen.c b/clang/test/OpenMP/task_codegen.c
index be404827ce901..0ca815c0eccf1 100644
--- a/clang/test/OpenMP/task_codegen.c
+++ b/clang/test/OpenMP/task_codegen.c
@@ -139,7 +139,8 @@ for (int i = 0; i < 10; ++i)
   // CHECK: [[EB_SUB_2_ADD_1_SUB:%.+]] = sub i32 [[EB_SUB_2_ADD]], 1
   // CHECK: [[EB_SUB_2_ADD_1_SUB_2_DIV:%.+]] = udiv i32 [[EB_SUB_2_ADD_1_SUB]], 2
   // CHECK: [[ELEMS:%.+]] = zext i32 [[EB_SUB_2_ADD_1_SUB_2_DIV]] to i64
-  // CHECK: [[NELEMS:%.+]] = mul nuw i64 [[ELEMS]], 1
+  // CHECK: [[ELEMS2:%.+]] = mul nuw i64 [[ELEMS]], 1
+  // CHECK: [[NELEMS:%.+]] = mul nuw i64 [[ELEMS2]], 1
 
   // ITERATOR_TOTAL = NELEMS + 0;
   // CHECK: [[ITERATOR_TOTAL:%.+]] = add nuw i64 0, [[NELEMS]]