[Clang][OpenMP] Enable tile/unroll on iterator- and foreach-loops (#91459)

OpenMP loop transformation did not work on a for-loop using an iterator
or range-based for-loops. The first reason is that it combined the
iterator's type for generated loops with the type of `NumIterations` as
generated for any `OMPLoopBasedDirective` which is an integer. Fixed by
basing all generated loop variables on `NumIterations`.

Second, C++11 range-based for-loops include syntactic sugar that needs
to be executed before the loop. This additional code is now added to the
construct's Pre-Init lists.

Third, C++20 added an initializer statement to range-based for-loops
which is also added to the pre-init statement. PreInits used to be a
`DeclStmt` which made it difficult to add arbitrary statements from
`CXXRangeForStmt`'s syntactic sugar, especially the for-loops init
statement which does not need to be a declaration. Change it to be a
general `Stmt` that can be a `CompoundStmt` to hold arbitrary Stmts,
including DeclStmts. This also avoids the `PointerUnion` workaround used
by `checkTransformableLoopNest`.

End-to-end tests are added to verify the expected number and order of
loop execution and evaluations of expressions (such as iterator
dereference). The order and number of evaluations of expressions in
canonical loops is explicitly undefined by OpenMP but checked here for
clarification and for changes to be noticed.

12 files changed, 1493 insertions, 0 deletions

diff --git a/openmp/runtime/test/lit.cfg b/openmp/runtime/test/lit.cfg
index e8f7f34..14c7468 100644
--- a/openmp/runtime/test/lit.cfg
+++ b/openmp/runtime/test/lit.cfg
@@ -171,10 +171,14 @@ config.substitutions.append(("%libomp-c99-compile-and-run", \
     "%libomp-c99-compile && %libomp-run"))
 config.substitutions.append(("%libomp-cxx-compile-and-run", \
     "%libomp-cxx-compile && %libomp-run"))
+config.substitutions.append(("%libomp-cxx20-compile-and-run", \
+    "%libomp-cxx20-compile && %libomp-run"))
 config.substitutions.append(("%libomp-cxx-compile-c", \
     "%clangXX %openmp_flags %flags -std=c++17 -x c++ %s -o %t" + libs))
 config.substitutions.append(("%libomp-cxx-compile", \
     "%clangXX %openmp_flags %flags -std=c++17 %s -o %t" + libs))
+config.substitutions.append(("%libomp-cxx20-compile", \
+    "%clangXX %openmp_flags %flags -std=c++20 %s -o %t" + libs))
 config.substitutions.append(("%libomp-compile", \
     "%clang %openmp_flags %flags %s -o %t" + libs))
 config.substitutions.append(("%libomp-irbuilder-compile", \
diff --git a/openmp/runtime/test/transform/tile/foreach.cpp b/openmp/runtime/test/transform/tile/foreach.cpp
new file mode 100644
index 0000000..4fb3595
--- /dev/null
+++ b/openmp/runtime/test/transform/tile/foreach.cpp
@@ -0,0 +1,228 @@
+// RUN: %libomp-cxx20-compile-and-run | FileCheck %s --match-full-lines
+
+#ifndef HEADER
+#define HEADER
+
+#include <cstdlib>
+#include <cstdarg>
+#include <cstdio>
+#include <vector>
+
+struct Reporter {
+  const char *name;
+
+  Reporter(const char *name) : name(name) { print("ctor"); }
+
+  Reporter() : name("<anon>") { print("ctor"); }
+
+  Reporter(const Reporter &that) : name(that.name) { print("copy ctor"); }
+
+  Reporter(Reporter &&that) : name(that.name) { print("move ctor"); }
+
+  ~Reporter() { print("dtor"); }
+
+  const Reporter &operator=(const Reporter &that) {
+    print("copy assign");
+    this->name = that.name;
+    return *this;
+  }
+
+  const Reporter &operator=(Reporter &&that) {
+    print("move assign");
+    this->name = that.name;
+    return *this;
+  }
+
+  struct Iterator {
+    const Reporter *owner;
+    int pos;
+
+    Iterator(const Reporter *owner, int pos) : owner(owner), pos(pos) {}
+
+    Iterator(const Iterator &that) : owner(that.owner), pos(that.pos) {
+      owner->print("iterator copy ctor");
+    }
+
+    Iterator(Iterator &&that) : owner(that.owner), pos(that.pos) {
+      owner->print("iterator move ctor");
+    }
+
+    ~Iterator() { owner->print("iterator dtor"); }
+
+    const Iterator &operator=(const Iterator &that) {
+      owner->print("iterator copy assign");
+      this->owner = that.owner;
+      this->pos = that.pos;
+      return *this;
+    }
+
+    const Iterator &operator=(Iterator &&that) {
+      owner->print("iterator move assign");
+      this->owner = that.owner;
+      this->pos = that.pos;
+      return *this;
+    }
+
+    bool operator==(const Iterator &that) const {
+      owner->print("iterator %d == %d", 2 - this->pos, 2 - that.pos);
+      return this->pos == that.pos;
+    }
+
+    Iterator &operator++() {
+      owner->print("iterator prefix ++");
+      pos -= 1;
+      return *this;
+    }
+
+    Iterator operator++(int) {
+      owner->print("iterator postfix ++");
+      auto result = *this;
+      pos -= 1;
+      return result;
+    }
+
+    int operator*() const {
+      int result = 2 - pos;
+      owner->print("iterator deref: %i", result);
+      return result;
+    }
+
+    size_t operator-(const Iterator &that) const {
+      int result = (2 - this->pos) - (2 - that.pos);
+      owner->print("iterator distance: %d", result);
+      return result;
+    }
+
+    Iterator operator+(int steps) const {
+      owner->print("iterator advance: %i += %i", 2 - this->pos, steps);
+      return Iterator(owner, pos - steps);
+    }
+
+    void print(const char *msg) const { owner->print(msg); }
+  };
+
+  Iterator begin() const {
+    print("begin()");
+    return Iterator(this, 2);
+  }
+
+  Iterator end() const {
+    print("end()");
+    return Iterator(this, -1);
+  }
+
+  void print(const char *msg, ...) const {
+    va_list args;
+    va_start(args, msg);
+    printf("[%s] ", name);
+    vprintf(msg, args);
+    printf("\n");
+    va_end(args);
+  }
+};
+
+int main() {
+  printf("do\n");
+#pragma omp tile sizes(2, 2)
+  for (Reporter c{"C"}; auto &&v : Reporter("A"))
+    for (Reporter d{"D"}; auto &&w : Reporter("B"))
+      printf("v=%d w=%d\n", v, w);
+  printf("done\n");
+  return EXIT_SUCCESS;
+}
+
+#endif /* HEADER */
+
+// CHECK:      do
+// CHECK-NEXT: [C] ctor
+// CHECK-NEXT: [A] ctor
+// CHECK-NEXT: [A] end()
+// CHECK-NEXT: [A] begin()
+// CHECK-NEXT: [A] begin()
+// CHECK-NEXT: [A] iterator distance: 3
+// CHECK-NEXT: [D] ctor
+// CHECK-NEXT: [B] ctor
+// CHECK-NEXT: [B] end()
+// CHECK-NEXT: [B] begin()
+// CHECK-NEXT: [B] begin()
+// CHECK-NEXT: [B] iterator distance: 3
+// CHECK-NEXT: [A] iterator advance: 0 += 0
+// CHECK-NEXT: [A] iterator move assign
+// CHECK-NEXT: [A] iterator deref: 0
+// CHECK-NEXT: [B] iterator advance: 0 += 0
+// CHECK-NEXT: [B] iterator move assign
+// CHECK-NEXT: [B] iterator deref: 0
+// CHECK-NEXT: v=0 w=0
+// CHECK-NEXT: [B] iterator dtor
+// CHECK-NEXT: [B] iterator advance: 0 += 1
+// CHECK-NEXT: [B] iterator move assign
+// CHECK-NEXT: [B] iterator deref: 1
+// CHECK-NEXT: v=0 w=1
+// CHECK-NEXT: [B] iterator dtor
+// CHECK-NEXT: [A] iterator dtor
+// CHECK-NEXT: [A] iterator advance: 0 += 1
+// CHECK-NEXT: [A] iterator move assign
+// CHECK-NEXT: [A] iterator deref: 1
+// CHECK-NEXT: [B] iterator advance: 0 += 0
+// CHECK-NEXT: [B] iterator move assign
+// CHECK-NEXT: [B] iterator deref: 0
+// CHECK-NEXT: v=1 w=0
+// CHECK-NEXT: [B] iterator dtor
+// CHECK-NEXT: [B] iterator advance: 0 += 1
+// CHECK-NEXT: [B] iterator move assign
+// CHECK-NEXT: [B] iterator deref: 1
+// CHECK-NEXT: v=1 w=1
+// CHECK-NEXT: [B] iterator dtor
+// CHECK-NEXT: [A] iterator dtor
+// CHECK-NEXT: [A] iterator advance: 0 += 0
+// CHECK-NEXT: [A] iterator move assign
+// CHECK-NEXT: [A] iterator deref: 0
+// CHECK-NEXT: [B] iterator advance: 0 += 2
+// CHECK-NEXT: [B] iterator move assign
+// CHECK-NEXT: [B] iterator deref: 2
+// CHECK-NEXT: v=0 w=2
+// CHECK-NEXT: [B] iterator dtor
+// CHECK-NEXT: [A] iterator dtor
+// CHECK-NEXT: [A] iterator advance: 0 += 1
+// CHECK-NEXT: [A] iterator move assign
+// CHECK-NEXT: [A] iterator deref: 1
+// CHECK-NEXT: [B] iterator advance: 0 += 2
+// CHECK-NEXT: [B] iterator move assign
+// CHECK-NEXT: [B] iterator deref: 2
+// CHECK-NEXT: v=1 w=2
+// CHECK-NEXT: [B] iterator dtor
+// CHECK-NEXT: [A] iterator dtor
+// CHECK-NEXT: [A] iterator advance: 0 += 2
+// CHECK-NEXT: [A] iterator move assign
+// CHECK-NEXT: [A] iterator deref: 2
+// CHECK-NEXT: [B] iterator advance: 0 += 0
+// CHECK-NEXT: [B] iterator move assign
+// CHECK-NEXT: [B] iterator deref: 0
+// CHECK-NEXT: v=2 w=0
+// CHECK-NEXT: [B] iterator dtor
+// CHECK-NEXT: [B] iterator advance: 0 += 1
+// CHECK-NEXT: [B] iterator move assign
+// CHECK-NEXT: [B] iterator deref: 1
+// CHECK-NEXT: v=2 w=1
+// CHECK-NEXT: [B] iterator dtor
+// CHECK-NEXT: [A] iterator dtor
+// CHECK-NEXT: [A] iterator advance: 0 += 2
+// CHECK-NEXT: [A] iterator move assign
+// CHECK-NEXT: [A] iterator deref: 2
+// CHECK-NEXT: [B] iterator advance: 0 += 2
+// CHECK-NEXT: [B] iterator move assign
+// CHECK-NEXT: [B] iterator deref: 2
+// CHECK-NEXT: v=2 w=2
+// CHECK-NEXT: [B] iterator dtor
+// CHECK-NEXT: [A] iterator dtor
+// CHECK-NEXT: [B] iterator dtor
+// CHECK-NEXT: [B] iterator dtor
+// CHECK-NEXT: [B] iterator dtor
+// CHECK-NEXT: [B] dtor
+// CHECK-NEXT: [D] dtor
+// CHECK-NEXT: [A] iterator dtor
+// CHECK-NEXT: [A] iterator dtor
+// CHECK-NEXT: [A] iterator dtor
+// CHECK-NEXT: [A] dtor
+// CHECK-NEXT: [C] dtor
+// CHECK-NEXT: done
diff --git a/openmp/runtime/test/transform/tile/iterfor.cpp b/openmp/runtime/test/transform/tile/iterfor.cpp
new file mode 100644
index 0000000..1261354
--- /dev/null
+++ b/openmp/runtime/test/transform/tile/iterfor.cpp
@@ -0,0 +1,233 @@
+// RUN: %libomp-cxx20-compile-and-run | FileCheck %s --match-full-lines
+
+#ifndef HEADER
+#define HEADER
+
+#include <cstdlib>
+#include <cstdarg>
+#include <cstdio>
+#include <vector>
+
+struct Reporter {
+  const char *name;
+
+  Reporter(const char *name) : name(name) { print("ctor"); }
+
+  Reporter() : name("<anon>") { print("ctor"); }
+
+  Reporter(const Reporter &that) : name(that.name) { print("copy ctor"); }
+
+  Reporter(Reporter &&that) : name(that.name) { print("move ctor"); }
+
+  ~Reporter() { print("dtor"); }
+
+  const Reporter &operator=(const Reporter &that) {
+    print("copy assign");
+    this->name = that.name;
+    return *this;
+  }
+
+  const Reporter &operator=(Reporter &&that) {
+    print("move assign");
+    this->name = that.name;
+    return *this;
+  }
+
+  struct Iterator {
+    const Reporter *owner;
+    int pos;
+
+    Iterator(const Reporter *owner, int pos) : owner(owner), pos(pos) {}
+
+    Iterator(const Iterator &that) : owner(that.owner), pos(that.pos) {
+      owner->print("iterator copy ctor");
+    }
+
+    Iterator(Iterator &&that) : owner(that.owner), pos(that.pos) {
+      owner->print("iterator move ctor");
+    }
+
+    ~Iterator() { owner->print("iterator dtor"); }
+
+    const Iterator &operator=(const Iterator &that) {
+      owner->print("iterator copy assign");
+      this->owner = that.owner;
+      this->pos = that.pos;
+      return *this;
+    }
+
+    const Iterator &operator=(Iterator &&that) {
+      owner->print("iterator move assign");
+      this->owner = that.owner;
+      this->pos = that.pos;
+      return *this;
+    }
+
+    bool operator==(const Iterator &that) const {
+      owner->print("iterator %d == %d", 2 - this->pos, 2 - that.pos);
+      return this->pos == that.pos;
+    }
+
+    bool operator!=(const Iterator &that) const {
+      owner->print("iterator %d != %d", 2 - this->pos, 2 - that.pos);
+      return this->pos == that.pos;
+    }
+
+    Iterator &operator++() {
+      owner->print("iterator prefix ++");
+      pos -= 1;
+      return *this;
+    }
+
+    Iterator operator++(int) {
+      owner->print("iterator postfix ++");
+      auto result = *this;
+      pos -= 1;
+      return result;
+    }
+
+    int operator*() const {
+      int result = 2 - pos;
+      owner->print("iterator deref: %i", result);
+      return result;
+    }
+
+    size_t operator-(const Iterator &that) const {
+      int result = (2 - this->pos) - (2 - that.pos);
+      owner->print("iterator distance: %d", result);
+      return result;
+    }
+
+    Iterator operator+(int steps) const {
+      owner->print("iterator advance: %i += %i", 2 - this->pos, steps);
+      return Iterator(owner, pos - steps);
+    }
+  };
+
+  Iterator begin() const {
+    print("begin()");
+    return Iterator(this, 2);
+  }
+
+  Iterator end() const {
+    print("end()");
+    return Iterator(this, -1);
+  }
+
+  void print(const char *msg, ...) const {
+    va_list args;
+    va_start(args, msg);
+    printf("[%s] ", name);
+    vprintf(msg, args);
+    printf("\n");
+    va_end(args);
+  }
+};
+
+int main() {
+  printf("do\n");
+  {
+    Reporter A("A"), B("B");
+#pragma omp tile sizes(2, 2)
+    for (auto it = A.begin(); it != A.end(); ++it)
+      for (auto jt = B.begin(); jt != B.end(); ++jt)
+        printf("i=%d j=%d\n", *it, *jt);
+  }
+  printf("done\n");
+  return EXIT_SUCCESS;
+}
+
+#endif /* HEADER */
+
+// CHECK:      do
+// CHECK-NEXT: [A] ctor
+// CHECK-NEXT: [B] ctor
+// CHECK-NEXT: [A] begin()
+// CHECK-NEXT: [A] begin()
+// CHECK-NEXT: [A] end()
+// CHECK-NEXT: [A] iterator distance: 3
+// CHECK-NEXT: [B] begin()
+// CHECK-NEXT: [B] begin()
+// CHECK-NEXT: [B] end()
+// CHECK-NEXT: [B] iterator distance: 3
+// CHECK-NEXT: [A] iterator advance: 0 += 0
+// CHECK-NEXT: [A] iterator move assign
+// CHECK-NEXT: [B] iterator advance: 0 += 0
+// CHECK-NEXT: [B] iterator move assign
+// CHECK-NEXT: [A] iterator deref: 0
+// CHECK-NEXT: [B] iterator deref: 0
+// CHECK-NEXT: i=0 j=0
+// CHECK-NEXT: [B] iterator dtor
+// CHECK-NEXT: [B] iterator advance: 0 += 1
+// CHECK-NEXT: [B] iterator move assign
+// CHECK-NEXT: [A] iterator deref: 0
+// CHECK-NEXT: [B] iterator deref: 1
+// CHECK-NEXT: i=0 j=1
+// CHECK-NEXT: [B] iterator dtor
+// CHECK-NEXT: [A] iterator dtor
+// CHECK-NEXT: [A] iterator advance: 0 += 1
+// CHECK-NEXT: [A] iterator move assign
+// CHECK-NEXT: [B] iterator advance: 0 += 0
+// CHECK-NEXT: [B] iterator move assign
+// CHECK-NEXT: [A] iterator deref: 1
+// CHECK-NEXT: [B] iterator deref: 0
+// CHECK-NEXT: i=1 j=0
+// CHECK-NEXT: [B] iterator dtor
+// CHECK-NEXT: [B] iterator advance: 0 += 1
+// CHECK-NEXT: [B] iterator move assign
+// CHECK-NEXT: [A] iterator deref: 1
+// CHECK-NEXT: [B] iterator deref: 1
+// CHECK-NEXT: i=1 j=1
+// CHECK-NEXT: [B] iterator dtor
+// CHECK-NEXT: [A] iterator dtor
+// CHECK-NEXT: [A] iterator advance: 0 += 0
+// CHECK-NEXT: [A] iterator move assign
+// CHECK-NEXT: [B] iterator advance: 0 += 2
+// CHECK-NEXT: [B] iterator move assign
+// CHECK-NEXT: [A] iterator deref: 0
+// CHECK-NEXT: [B] iterator deref: 2
+// CHECK-NEXT: i=0 j=2
+// CHECK-NEXT: [B] iterator dtor
+// CHECK-NEXT: [A] iterator dtor
+// CHECK-NEXT: [A] iterator advance: 0 += 1
+// CHECK-NEXT: [A] iterator move assign
+// CHECK-NEXT: [B] iterator advance: 0 += 2
+// CHECK-NEXT: [B] iterator move assign
+// CHECK-NEXT: [A] iterator deref: 1
+// CHECK-NEXT: [B] iterator deref: 2
+// CHECK-NEXT: i=1 j=2
+// CHECK-NEXT: [B] iterator dtor
+// CHECK-NEXT: [A] iterator dtor
+// CHECK-NEXT: [A] iterator advance: 0 += 2
+// CHECK-NEXT: [A] iterator move assign
+// CHECK-NEXT: [B] iterator advance: 0 += 0
+// CHECK-NEXT: [B] iterator move assign
+// CHECK-NEXT: [A] iterator deref: 2
+// CHECK-NEXT: [B] iterator deref: 0
+// CHECK-NEXT: i=2 j=0
+// CHECK-NEXT: [B] iterator dtor
+// CHECK-NEXT: [B] iterator advance: 0 += 1
+// CHECK-NEXT: [B] iterator move assign
+// CHECK-NEXT: [A] iterator deref: 2
+// CHECK-NEXT: [B] iterator deref: 1
+// CHECK-NEXT: i=2 j=1
+// CHECK-NEXT: [B] iterator dtor
+// CHECK-NEXT: [A] iterator dtor
+// CHECK-NEXT: [A] iterator advance: 0 += 2
+// CHECK-NEXT: [A] iterator move assign
+// CHECK-NEXT: [B] iterator advance: 0 += 2
+// CHECK-NEXT: [B] iterator move assign
+// CHECK-NEXT: [A] iterator deref: 2
+// CHECK-NEXT: [B] iterator deref: 2
+// CHECK-NEXT: i=2 j=2
+// CHECK-NEXT: [B] iterator dtor
+// CHECK-NEXT: [A] iterator dtor
+// CHECK-NEXT: [B] iterator dtor
+// CHECK-NEXT: [B] iterator dtor
+// CHECK-NEXT: [A] iterator dtor
+// CHECK-NEXT: [A] iterator dtor
+// CHECK-NEXT: [B] iterator dtor
+// CHECK-NEXT: [A] iterator dtor
+// CHECK-NEXT: [B] dtor
+// CHECK-NEXT: [A] dtor
+// CHECK-NEXT: done
diff --git a/openmp/runtime/test/transform/tile/parallel-wsloop-collapse-foreach.cpp b/openmp/runtime/test/transform/tile/parallel-wsloop-collapse-foreach.cpp
new file mode 100644
index 0000000..b1f4d98
--- /dev/null
+++ b/openmp/runtime/test/transform/tile/parallel-wsloop-collapse-foreach.cpp
@@ -0,0 +1,366 @@
+// RUN: %libomp-cxx20-compile-and-run | FileCheck %s --match-full-lines
+
+#ifndef HEADER
+#define HEADER
+
+#include <cstdlib>
+#include <cstdarg>
+#include <cstdio>
+#include <vector>
+
+struct Reporter {
+  const char *name;
+
+  Reporter(const char *name) : name(name) { print("ctor"); }
+
+  Reporter() : name("<anon>") { print("ctor"); }
+
+  Reporter(const Reporter &that) : name(that.name) { print("copy ctor"); }
+
+  Reporter(Reporter &&that) : name(that.name) { print("move ctor"); }
+
+  ~Reporter() { print("dtor"); }
+
+  const Reporter &operator=(const Reporter &that) {
+    print("copy assign");
+    this->name = that.name;
+    return *this;
+  }
+
+  const Reporter &operator=(Reporter &&that) {
+    print("move assign");
+    this->name = that.name;
+    return *this;
+  }
+
+  struct Iterator {
+    const Reporter *owner;
+    int pos;
+
+    Iterator(const Reporter *owner, int pos) : owner(owner), pos(pos) {}
+
+    Iterator(const Iterator &that) : owner(that.owner), pos(that.pos) {
+      owner->print("iterator copy ctor");
+    }
+
+    Iterator(Iterator &&that) : owner(that.owner), pos(that.pos) {
+      owner->print("iterator move ctor");
+    }
+
+    ~Iterator() { owner->print("iterator dtor"); }
+
+    const Iterator &operator=(const Iterator &that) {
+      owner->print("iterator copy assign");
+      this->owner = that.owner;
+      this->pos = that.pos;
+      return *this;
+    }
+
+    const Iterator &operator=(Iterator &&that) {
+      owner->print("iterator move assign");
+      this->owner = that.owner;
+      this->pos = that.pos;
+      return *this;
+    }
+
+    bool operator==(const Iterator &that) const {
+      owner->print("iterator %d == %d", 2 - this->pos, 2 - that.pos);
+      return this->pos == that.pos;
+    }
+
+    Iterator &operator++() {
+      owner->print("iterator prefix ++");
+      pos -= 1;
+      return *this;
+    }
+
+    Iterator operator++(int) {
+      owner->print("iterator postfix ++");
+      auto result = *this;
+      pos -= 1;
+      return result;
+    }
+
+    int operator*() const {
+      int result = 2 - pos;
+      owner->print("iterator deref: %i", result);
+      return result;
+    }
+
+    size_t operator-(const Iterator &that) const {
+      int result = (2 - this->pos) - (2 - that.pos);
+      owner->print("iterator distance: %d", result);
+      return result;
+    }
+
+    Iterator operator+(int steps) const {
+      owner->print("iterator advance: %i += %i", 2 - this->pos, steps);
+      return Iterator(owner, pos - steps);
+    }
+  };
+
+  Iterator begin() const {
+    print("begin()");
+    return Iterator(this, 2);
+  }
+
+  Iterator end() const {
+    print("end()");
+    return Iterator(this, -1);
+  }
+
+  void print(const char *msg, ...) const {
+    va_list args;
+    va_start(args, msg);
+    printf("[%s] ", name);
+    vprintf(msg, args);
+    printf("\n");
+    va_end(args);
+  }
+};
+
+int main() {
+  printf("do\n");
+#pragma omp parallel for collapse(3) num_threads(1)
+  for (int i = 0; i < 3; ++i)
+#pragma omp tile sizes(2, 2)
+    for (Reporter c{"C"}; auto &&v : Reporter("A"))
+      for (Reporter d{"D"}; auto &&w : Reporter("B"))
+        printf("i=%d v=%d w=%d\n", i, v, w);
+  printf("done\n");
+  return EXIT_SUCCESS;
+}
+
+#endif /* HEADER */
+
+// CHECK:      do
+// CHECK-NEXT: [C] ctor
+// CHECK-NEXT: [A] ctor
+// CHECK-NEXT: [A] end()
+// CHECK-NEXT: [A] begin()
+// CHECK-NEXT: [A] begin()
+// CHECK-NEXT: [A] iterator distance: 3
+// CHECK-NEXT: [D] ctor
+// CHECK-NEXT: [B] ctor
+// CHECK-NEXT: [B] end()
+// CHECK-NEXT: [B] begin()
+// CHECK-NEXT: [B] begin()
+// CHECK-NEXT: [B] iterator distance: 3
+// CHECK-NEXT: [A] iterator advance: 0 += 0
+// CHECK-NEXT: [A] iterator move assign
+// CHECK-NEXT: [A] iterator deref: 0
+// CHECK-NEXT: [B] iterator advance: 0 += 0
+// CHECK-NEXT: [B] iterator move assign
+// CHECK-NEXT: [B] iterator deref: 0
+// CHECK-NEXT: i=0 v=0 w=0
+// CHECK-NEXT: [B] iterator dtor
+// CHECK-NEXT: [B] iterator advance: 0 += 1
+// CHECK-NEXT: [B] iterator move assign
+// CHECK-NEXT: [B] iterator deref: 1
+// CHECK-NEXT: i=0 v=0 w=1
+// CHECK-NEXT: [B] iterator dtor
+// CHECK-NEXT: [A] iterator dtor
+// CHECK-NEXT: [A] iterator advance: 0 += 1
+// CHECK-NEXT: [A] iterator move assign
+// CHECK-NEXT: [A] iterator deref: 1
+// CHECK-NEXT: [B] iterator advance: 0 += 0
+// CHECK-NEXT: [B] iterator move assign
+// CHECK-NEXT: [B] iterator deref: 0
+// CHECK-NEXT: i=0 v=1 w=0
+// CHECK-NEXT: [B] iterator dtor
+// CHECK-NEXT: [B] iterator advance: 0 += 1
+// CHECK-NEXT: [B] iterator move assign
+// CHECK-NEXT: [B] iterator deref: 1
+// CHECK-NEXT: i=0 v=1 w=1
+// CHECK-NEXT: [B] iterator dtor
+// CHECK-NEXT: [A] iterator dtor
+// CHECK-NEXT: [A] iterator advance: 0 += 0
+// CHECK-NEXT: [A] iterator move assign
+// CHECK-NEXT: [A] iterator deref: 0
+// CHECK-NEXT: [B] iterator advance: 0 += 2
+// CHECK-NEXT: [B] iterator move assign
+// CHECK-NEXT: [B] iterator deref: 2
+// CHECK-NEXT: i=0 v=0 w=2
+// CHECK-NEXT: [B] iterator dtor
+// CHECK-NEXT: [A] iterator dtor
+// CHECK-NEXT: [A] iterator advance: 0 += 1
+// CHECK-NEXT: [A] iterator move assign
+// CHECK-NEXT: [A] iterator deref: 1
+// CHECK-NEXT: [B] iterator advance: 0 += 2
+// CHECK-NEXT: [B] iterator move assign
+// CHECK-NEXT: [B] iterator deref: 2
+// CHECK-NEXT: i=0 v=1 w=2
+// CHECK-NEXT: [B] iterator dtor
+// CHECK-NEXT: [A] iterator dtor
+// CHECK-NEXT: [A] iterator advance: 0 += 2
+// CHECK-NEXT: [A] iterator move assign
+// CHECK-NEXT: [A] iterator deref: 2
+// CHECK-NEXT: [B] iterator advance: 0 += 0
+// CHECK-NEXT: [B] iterator move assign
+// CHECK-NEXT: [B] iterator deref: 0
+// CHECK-NEXT: i=0 v=2 w=0
+// CHECK-NEXT: [B] iterator dtor
+// CHECK-NEXT: [B] iterator advance: 0 += 1
+// CHECK-NEXT: [B] iterator move assign
+// CHECK-NEXT: [B] iterator deref: 1
+// CHECK-NEXT: i=0 v=2 w=1
+// CHECK-NEXT: [B] iterator dtor
+// CHECK-NEXT: [A] iterator dtor
+// CHECK-NEXT: [A] iterator advance: 0 += 2
+// CHECK-NEXT: [A] iterator move assign
+// CHECK-NEXT: [A] iterator deref: 2
+// CHECK-NEXT: [B] iterator advance: 0 += 2
+// CHECK-NEXT: [B] iterator move assign
+// CHECK-NEXT: [B] iterator deref: 2
+// CHECK-NEXT: i=0 v=2 w=2
+// CHECK-NEXT: [B] iterator dtor
+// CHECK-NEXT: [A] iterator dtor
+// CHECK-NEXT: [A] iterator advance: 0 += 0
+// CHECK-NEXT: [A] iterator move assign
+// CHECK-NEXT: [A] iterator deref: 0
+// CHECK-NEXT: [B] iterator advance: 0 += 0
+// CHECK-NEXT: [B] iterator move assign
+// CHECK-NEXT: [B] iterator deref: 0
+// CHECK-NEXT: i=1 v=0 w=0
+// CHECK-NEXT: [B] iterator dtor
+// CHECK-NEXT: [B] iterator advance: 0 += 1
+// CHECK-NEXT: [B] iterator move assign
+// CHECK-NEXT: [B] iterator deref: 1
+// CHECK-NEXT: i=1 v=0 w=1
+// CHECK-NEXT: [B] iterator dtor
+// CHECK-NEXT: [A] iterator dtor
+// CHECK-NEXT: [A] iterator advance: 0 += 1
+// CHECK-NEXT: [A] iterator move assign
+// CHECK-NEXT: [A] iterator deref: 1
+// CHECK-NEXT: [B] iterator advance: 0 += 0
+// CHECK-NEXT: [B] iterator move assign
+// CHECK-NEXT: [B] iterator deref: 0
+// CHECK-NEXT: i=1 v=1 w=0
+// CHECK-NEXT: [B] iterator dtor
+// CHECK-NEXT: [B] iterator advance: 0 += 1
+// CHECK-NEXT: [B] iterator move assign
+// CHECK-NEXT: [B] iterator deref: 1
+// CHECK-NEXT: i=1 v=1 w=1
+// CHECK-NEXT: [B] iterator dtor
+// CHECK-NEXT: [A] iterator dtor
+// CHECK-NEXT: [A] iterator advance: 0 += 0
+// CHECK-NEXT: [A] iterator move assign
+// CHECK-NEXT: [A] iterator deref: 0
+// CHECK-NEXT: [B] iterator advance: 0 += 2
+// CHECK-NEXT: [B] iterator move assign
+// CHECK-NEXT: [B] iterator deref: 2
+// CHECK-NEXT: i=1 v=0 w=2
+// CHECK-NEXT: [B] iterator dtor
+// CHECK-NEXT: [A] iterator dtor
+// CHECK-NEXT: [A] iterator advance: 0 += 1
+// CHECK-NEXT: [A] iterator move assign
+// CHECK-NEXT: [A] iterator deref: 1
+// CHECK-NEXT: [B] iterator advance: 0 += 2
+// CHECK-NEXT: [B] iterator move assign
+// CHECK-NEXT: [B] iterator deref: 2
+// CHECK-NEXT: i=1 v=1 w=2
+// CHECK-NEXT: [B] iterator dtor
+// CHECK-NEXT: [A] iterator dtor
+// CHECK-NEXT: [A] iterator advance: 0 += 2
+// CHECK-NEXT: [A] iterator move assign
+// CHECK-NEXT: [A] iterator deref: 2
+// CHECK-NEXT: [B] iterator advance: 0 += 0
+// CHECK-NEXT: [B] iterator move assign
+// CHECK-NEXT: [B] iterator deref: 0
+// CHECK-NEXT: i=1 v=2 w=0
+// CHECK-NEXT: [B] iterator dtor
+// CHECK-NEXT: [B] iterator advance: 0 += 1
+// CHECK-NEXT: [B] iterator move assign
+// CHECK-NEXT: [B] iterator deref: 1
+// CHECK-NEXT: i=1 v=2 w=1
+// CHECK-NEXT: [B] iterator dtor
+// CHECK-NEXT: [A] iterator dtor
+// CHECK-NEXT: [A] iterator advance: 0 += 2
+// CHECK-NEXT: [A] iterator move assign
+// CHECK-NEXT: [A] iterator deref: 2
+// CHECK-NEXT: [B] iterator advance: 0 += 2
+// CHECK-NEXT: [B] iterator move assign
+// CHECK-NEXT: [B] iterator deref: 2
+// CHECK-NEXT: i=1 v=2 w=2
+// CHECK-NEXT: [B] iterator dtor
+// CHECK-NEXT: [A] iterator dtor
+// CHECK-NEXT: [A] iterator advance: 0 += 0
+// CHECK-NEXT: [A] iterator move assign
+// CHECK-NEXT: [A] iterator deref: 0
+// CHECK-NEXT: [B] iterator advance: 0 += 0
+// CHECK-NEXT: [B] iterator move assign
+// CHECK-NEXT: [B] iterator deref: 0
+// CHECK-NEXT: i=2 v=0 w=0
+// CHECK-NEXT: [B] iterator dtor
+// CHECK-NEXT: [B] iterator advance: 0 += 1
+// CHECK-NEXT: [B] iterator move assign
+// CHECK-NEXT: [B] iterator deref: 1
+// CHECK-NEXT: i=2 v=0 w=1
+// CHECK-NEXT: [B] iterator dtor
+// CHECK-NEXT: [A] iterator dtor
+// CHECK-NEXT: [A] iterator advance: 0 += 1
+// CHECK-NEXT: [A] iterator move assign
+// CHECK-NEXT: [A] iterator deref: 1
+// CHECK-NEXT: [B] iterator advance: 0 += 0
+// CHECK-NEXT: [B] iterator move assign
+// CHECK-NEXT: [B] iterator deref: 0
+// CHECK-NEXT: i=2 v=1 w=0
+// CHECK-NEXT: [B] iterator dtor
+// CHECK-NEXT: [B] iterator advance: 0 += 1
+// CHECK-NEXT: [B] iterator move assign
+// CHECK-NEXT: [B] iterator deref: 1
+// CHECK-NEXT: i=2 v=1 w=1
+// CHECK-NEXT: [B] iterator dtor
+// CHECK-NEXT: [A] iterator dtor
+// CHECK-NEXT: [A] iterator advance: 0 += 0
+// CHECK-NEXT: [A] iterator move assign
+// CHECK-NEXT: [A] iterator deref: 0
+// CHECK-NEXT: [B] iterator advance: 0 += 2
+// CHECK-NEXT: [B] iterator move assign
+// CHECK-NEXT: [B] iterator deref: 2
+// CHECK-NEXT: i=2 v=0 w=2
+// CHECK-NEXT: [B] iterator dtor
+// CHECK-NEXT: [A] iterator dtor
+// CHECK-NEXT: [A] iterator advance: 0 += 1
+// CHECK-NEXT: [A] iterator move assign
+// CHECK-NEXT: [A] iterator deref: 1
+// CHECK-NEXT: [B] iterator advance: 0 += 2
+// CHECK-NEXT: [B] iterator move assign
+// CHECK-NEXT: [B] iterator deref: 2
+// CHECK-NEXT: i=2 v=1 w=2
+// CHECK-NEXT: [B] iterator dtor
+// CHECK-NEXT: [A] iterator dtor
+// CHECK-NEXT: [A] iterator advance: 0 += 2
+// CHECK-NEXT: [A] iterator move assign
+// CHECK-NEXT: [A] iterator deref: 2
+// CHECK-NEXT: [B] iterator advance: 0 += 0
+// CHECK-NEXT: [B] iterator move assign
+// CHECK-NEXT: [B] iterator deref: 0
+// CHECK-NEXT: i=2 v=2 w=0
+// CHECK-NEXT: [B] iterator dtor
+// CHECK-NEXT: [B] iterator advance: 0 += 1
+// CHECK-NEXT: [B] iterator move assign
+// CHECK-NEXT: [B] iterator deref: 1
+// CHECK-NEXT: i=2 v=2 w=1
+// CHECK-NEXT: [B] iterator dtor
+// CHECK-NEXT: [A] iterator dtor
+// CHECK-NEXT: [A] iterator advance: 0 += 2
+// CHECK-NEXT: [A] iterator move assign
+// CHECK-NEXT: [A] iterator deref: 2
+// CHECK-NEXT: [B] iterator advance: 0 += 2
+// CHECK-NEXT: [B] iterator move assign
+// CHECK-NEXT: [B] iterator deref: 2
+// CHECK-NEXT: i=2 v=2 w=2
+// CHECK-NEXT: [B] iterator dtor
+// CHECK-NEXT: [A] iterator dtor
+// CHECK-NEXT: [B] iterator dtor
+// CHECK-NEXT: [B] iterator dtor
+// CHECK-NEXT: [B] iterator dtor
+// CHECK-NEXT: [B] dtor
+// CHECK-NEXT: [D] dtor
+// CHECK-NEXT: [A] iterator dtor
+// CHECK-NEXT: [A] iterator dtor
+// CHECK-NEXT: [A] iterator dtor
+// CHECK-NEXT: [A] dtor
+// CHECK-NEXT: [C] dtor
+// CHECK-NEXT: done
diff --git a/openmp/runtime/test/transform/unroll/factor_foreach.cpp b/openmp/runtime/test/transform/unroll/factor_foreach.cpp
new file mode 100644
index 0000000..29fef7c
--- /dev/null
+++ b/openmp/runtime/test/transform/unroll/factor_foreach.cpp
@@ -0,0 +1,162 @@
+// RUN: %libomp-cxx20-compile-and-run | FileCheck %s --match-full-lines
+
+#ifndef HEADER
+#define HEADER
+
+#include <cstdlib>
+#include <cstdarg>
+#include <cstdio>
+#include <vector>
+
+struct Reporter {
+  const char *name;
+
+  Reporter(const char *name) : name(name) { print("ctor"); }
+
+  Reporter() : name("<anon>") { print("ctor"); }
+
+  Reporter(const Reporter &that) : name(that.name) { print("copy ctor"); }
+
+  Reporter(Reporter &&that) : name(that.name) { print("move ctor"); }
+
+  ~Reporter() { print("dtor"); }
+
+  const Reporter &operator=(const Reporter &that) {
+    print("copy assign");
+    this->name = that.name;
+    return *this;
+  }
+
+  const Reporter &operator=(Reporter &&that) {
+    print("move assign");
+    this->name = that.name;
+    return *this;
+  }
+
+  struct Iterator {
+    const Reporter *owner;
+    int pos;
+
+    Iterator(const Reporter *owner, int pos) : owner(owner), pos(pos) {}
+
+    Iterator(const Iterator &that) : owner(that.owner), pos(that.pos) {
+      owner->print("iterator copy ctor");
+    }
+
+    Iterator(Iterator &&that) : owner(that.owner), pos(that.pos) {
+      owner->print("iterator move ctor");
+    }
+
+    ~Iterator() { owner->print("iterator dtor"); }
+
+    const Iterator &operator=(const Iterator &that) {
+      owner->print("iterator copy assign");
+      this->owner = that.owner;
+      this->pos = that.pos;
+      return *this;
+    }
+
+    const Iterator &operator=(Iterator &&that) {
+      owner->print("iterator move assign");
+      this->owner = that.owner;
+      this->pos = that.pos;
+      return *this;
+    }
+
+    bool operator==(const Iterator &that) const {
+      owner->print("iterator %d == %d", 2 - this->pos, 2 - that.pos);
+      return this->pos == that.pos;
+    }
+
+    bool operator!=(const Iterator &that) const {
+      owner->print("iterator %d != %d", 2 - this->pos, 2 - that.pos);
+      return this->pos != that.pos;
+    }
+
+    Iterator &operator++() {
+      owner->print("iterator prefix ++");
+      pos -= 1;
+      return *this;
+    }
+
+    Iterator operator++(int) {
+      owner->print("iterator postfix ++");
+      auto result = *this;
+      pos -= 1;
+      return result;
+    }
+
+    int operator*() const {
+      int result = 2 - pos;
+      owner->print("iterator deref: %i", result);
+      return result;
+    }
+
+    size_t operator-(const Iterator &that) const {
+      int result = (2 - this->pos) - (2 - that.pos);
+      owner->print("iterator distance: %d", result);
+      return result;
+    }
+
+    Iterator operator+(int steps) const {
+      owner->print("iterator advance: %i += %i", 2 - this->pos, steps);
+      return Iterator(owner, pos - steps);
+    }
+
+    void print(const char *msg) const { owner->print(msg); }
+  };
+
+  Iterator begin() const {
+    print("begin()");
+    return Iterator(this, 2);
+  }
+
+  Iterator end() const {
+    print("end()");
+    return Iterator(this, -1);
+  }
+
+  void print(const char *msg, ...) const {
+    va_list args;
+    va_start(args, msg);
+    printf("[%s] ", name);
+    vprintf(msg, args);
+    printf("\n");
+    va_end(args);
+  }
+};
+
+int main() {
+  printf("do\n");
+#pragma omp unroll partial(2)
+  for (Reporter c{"init-stmt"}; auto &&v : Reporter("range"))
+    printf("v=%d\n", v);
+  printf("done\n");
+  return EXIT_SUCCESS;
+}
+
+#endif /* HEADER */
+
+// CHECK:      do
+// CHECK-NEXT: [init-stmt] ctor
+// CHECK-NEXT: [range] ctor
+// CHECK-NEXT: [range] begin()
+// CHECK-NEXT: [range] end()
+// CHECK-NEXT: [range] iterator 0 != 3
+// CHECK-NEXT: [range] iterator deref: 0
+// CHECK-NEXT: v=0
+// CHECK-NEXT: [range] iterator prefix ++
+// CHECK-NEXT: [range] iterator 1 != 3
+// CHECK-NEXT: [range] iterator deref: 1
+// CHECK-NEXT: v=1
+// CHECK-NEXT: [range] iterator prefix ++
+// CHECK-NEXT: [range] iterator 2 != 3
+// CHECK-NEXT: [range] iterator deref: 2
+// CHECK-NEXT: v=2
+// CHECK-NEXT: [range] iterator prefix ++
+// CHECK-NEXT: [range] iterator 3 != 3
+// CHECK-NEXT: [range] iterator dtor
+// CHECK-NEXT: [range] iterator dtor
+// CHECK-NEXT: [range] dtor
+// CHECK-NEXT: [init-stmt] dtor
+// CHECK-NEXT: done
diff --git a/openmp/runtime/test/transform/unroll/factor_intfor.c b/openmp/runtime/test/transform/unroll/factor_intfor.c
new file mode 100644
index 0000000..42ebeb4
--- /dev/null
+++ b/openmp/runtime/test/transform/unroll/factor_intfor.c
@@ -0,0 +1,25 @@
+// RUN: %libomp-compile-and-run | FileCheck %s --match-full-lines
+
+#ifndef HEADER
+#define HEADER
+
+#include <stdlib.h>
+#include <stdio.h>
+
+int main() {
+  printf("do\n");
+#pragma omp unroll partial(2)
+  for (int i = 7; i < 19; i += 3)
+    printf("i=%d\n", i);
+  printf("done\n");
+  return EXIT_SUCCESS;
+}
+
+#endif /* HEADER */
+
+// CHECK:      do
+// CHECK-NEXT: i=7
+// CHECK-NEXT: i=10
+// CHECK-NEXT: i=13
+// CHECK-NEXT: i=16
+// CHECK-NEXT: done
diff --git a/openmp/runtime/test/transform/unroll/factor_iterfor.cpp b/openmp/runtime/test/transform/unroll/factor_iterfor.cpp
new file mode 100644
index 0000000..0298477
--- /dev/null
+++ b/openmp/runtime/test/transform/unroll/factor_iterfor.cpp
@@ -0,0 +1,169 @@
+// RUN: %libomp-cxx20-compile-and-run | FileCheck %s --match-full-lines
+
+#ifndef HEADER
+#define HEADER
+
+#include <cstdlib>
+#include <cstdarg>
+#include <cstdio>
+#include <vector>
+
+struct Reporter {
+  const char *name;
+
+  Reporter(const char *name) : name(name) { print("ctor"); }
+
+  Reporter() : name("<anon>") { print("ctor"); }
+
+  Reporter(const Reporter &that) : name(that.name) { print("copy ctor"); }
+
+  Reporter(Reporter &&that) : name(that.name) { print("move ctor"); }
+
+  ~Reporter() { print("dtor"); }
+
+  const Reporter &operator=(const Reporter &that) {
+    print("copy assign");
+    this->name = that.name;
+    return *this;
+  }
+
+  const Reporter &operator=(Reporter &&that) {
+    print("move assign");
+    this->name = that.name;
+    return *this;
+  }
+
+  struct Iterator {
+    const Reporter *owner;
+    int pos;
+
+    Iterator(const Reporter *owner, int pos) : owner(owner), pos(pos) {}
+
+    Iterator(const Iterator &that) : owner(that.owner), pos(that.pos) {
+      print("iterator copy ctor");
+    }
+
+    Iterator(Iterator &&that) : owner(that.owner), pos(that.pos) {
+      print("iterator move ctor");
+    }
+
+    ~Iterator() { print("iterator dtor"); }
+
+    const Iterator &operator=(const Iterator &that) {
+      print("iterator copy assign");
+      this->owner = that.owner;
+      this->pos = that.pos;
+      return *this;
+    }
+
+    const Iterator &operator=(Iterator &&that) {
+      print("iterator move assign");
+      this->owner = that.owner;
+      this->pos = that.pos;
+      return *this;
+    }
+
+    bool operator==(const Iterator &that) const {
+      owner->print("iterator %d == %d", 2 - this->pos, 2 - that.pos);
+      return this->pos == that.pos;
+    }
+
+    bool operator!=(const Iterator &that) const {
+      owner->print("iterator %d != %d", 2 - this->pos, 2 - that.pos);
+      return this->pos != that.pos;
+    }
+
+    Iterator &operator++() {
+      print("iterator prefix ++");
+      pos -= 1;
+      return *this;
+    }
+
+    Iterator operator++(int) {
+      print("iterator postfix ++");
+      auto result = *this;
+      pos -= 1;
+      return result;
+    }
+
+    int operator*() const {
+      int result = 2 - pos;
+      owner->print("iterator deref: %i", result);
+      return result;
+    }
+
+    size_t operator-(const Iterator &that) const {
+      int result = (2 - this->pos) - (2 - that.pos);
+      owner->print("iterator distance: %d", result);
+      return result;
+    }
+
+    Iterator operator+(int steps) const {
+      owner->print("iterator advance: %i += %i", 2 - this->pos, steps);
+      return Iterator(owner, pos - steps);
+    }
+
+    void print(const char *msg) const { owner->print(msg); }
+  };
+
+  Iterator begin() const {
+    print("begin()");
+    return Iterator(this, 2);
+  }
+
+  Iterator end() const {
+    print("end()");
+    return Iterator(this, -1);
+  }
+
+  void print(const char *msg, ...) const {
+    va_list args;
+    va_start(args, msg);
+    printf("[%s] ", name);
+    vprintf(msg, args);
+    printf("\n");
+    va_end(args);
+  }
+};
+
+int main() {
+  printf("do\n");
+  {
+    Reporter range("range");
+#pragma omp unroll partial(2)
+    for (auto it = range.begin(); it != range.end(); ++it)
+      printf("v=%d\n", *it);
+  }
+  printf("done\n");
+  return EXIT_SUCCESS;
+}
+
+#endif /* HEADER */
+
+// CHECK:      do
+// CHECK-NEXT: [range] ctor
+// CHECK-NEXT: [range] begin()
+// CHECK-NEXT: [range] end()
+// CHECK-NEXT: [range] iterator 0 != 3
+// CHECK-NEXT: [range] iterator deref: 0
+// CHECK-NEXT: v=0
+// CHECK-NEXT: [range] iterator prefix ++
+// CHECK-NEXT: [range] iterator dtor
+// CHECK-NEXT: [range] end()
+// CHECK-NEXT: [range] iterator 1 != 3
+// CHECK-NEXT: [range] iterator deref: 1
+// CHECK-NEXT: v=1
+// CHECK-NEXT: [range] iterator prefix ++
+// CHECK-NEXT: [range] iterator dtor
+// CHECK-NEXT: [range] end()
+// CHECK-NEXT: [range] iterator 2 != 3
+// CHECK-NEXT: [range] iterator deref: 2
+// CHECK-NEXT: v=2
+// CHECK-NEXT: [range] iterator prefix ++
+// CHECK-NEXT: [range] iterator dtor
+// CHECK-NEXT: [range] end()
+// CHECK-NEXT: [range] iterator 3 != 3
+// CHECK-NEXT: [range] iterator dtor
+// CHECK-NEXT: [range] iterator dtor
+// CHECK-NEXT: [range] dtor
+// CHECK-NEXT: done
diff --git a/openmp/runtime/test/transform/unroll/factor_parallel-wsloop-collapse-foreach.cpp b/openmp/runtime/test/transform/unroll/factor_parallel-wsloop-collapse-foreach.cpp
new file mode 100644
index 0000000..71567fa
--- /dev/null
+++ b/openmp/runtime/test/transform/unroll/factor_parallel-wsloop-collapse-foreach.cpp
@@ -0,0 +1,199 @@
+// RUN: %libomp-cxx20-compile-and-run | FileCheck %s --match-full-lines
+
+#ifndef HEADER
+#define HEADER
+
+#include <cstdlib>
+#include <cstdarg>
+#include <cstdio>
+#include <vector>
+
+struct Reporter {
+  const char *name;
+
+  Reporter(const char *name) : name(name) { print("ctor"); }
+
+  Reporter() : name("<anon>") { print("ctor"); }
+
+  Reporter(const Reporter &that) : name(that.name) { print("copy ctor"); }
+
+  Reporter(Reporter &&that) : name(that.name) { print("move ctor"); }
+
+  ~Reporter() { print("dtor"); }
+
+  const Reporter &operator=(const Reporter &that) {
+    print("copy assign");
+    this->name = that.name;
+    return *this;
+  }
+
+  const Reporter &operator=(Reporter &&that) {
+    print("move assign");
+    this->name = that.name;
+    return *this;
+  }
+
+  struct Iterator {
+    const Reporter *owner;
+    int pos;
+
+    Iterator(const Reporter *owner, int pos) : owner(owner), pos(pos) {}
+
+    Iterator(const Iterator &that) : owner(that.owner), pos(that.pos) {
+      owner->print("iterator copy ctor");
+    }
+
+    Iterator(Iterator &&that) : owner(that.owner), pos(that.pos) {
+      owner->print("iterator move ctor");
+    }
+
+    ~Iterator() { owner->print("iterator dtor"); }
+
+    const Iterator &operator=(const Iterator &that) {
+      owner->print("iterator copy assign");
+      this->owner = that.owner;
+      this->pos = that.pos;
+      return *this;
+    }
+
+    const Iterator &operator=(Iterator &&that) {
+      owner->print("iterator move assign");
+      this->owner = that.owner;
+      this->pos = that.pos;
+      return *this;
+    }
+
+    bool operator==(const Iterator &that) const {
+      owner->print("iterator %d == %d", 2 - this->pos, 2 - that.pos);
+      return this->pos == that.pos;
+    }
+
+    bool operator!=(const Iterator &that) const {
+      owner->print("iterator %d != %d", 2 - this->pos, 2 - that.pos);
+      return this->pos != that.pos;
+    }
+
+    Iterator &operator++() {
+      owner->print("iterator prefix ++");
+      pos -= 1;
+      return *this;
+    }
+
+    Iterator operator++(int) {
+      owner->print("iterator postfix ++");
+      auto result = *this;
+      pos -= 1;
+      return result;
+    }
+
+    int operator*() const {
+      int result = 2 - pos;
+      owner->print("iterator deref: %i", result);
+      return result;
+    }
+
+    size_t operator-(const Iterator &that) const {
+      int result = (2 - this->pos) - (2 - that.pos);
+      owner->print("iterator distance: %d", result);
+      return result;
+    }
+
+    Iterator operator+(int steps) const {
+      owner->print("iterator advance: %i += %i", 2 - this->pos, steps);
+      return Iterator(owner, pos - steps);
+    }
+
+    void print(const char *msg) const { owner->print(msg); }
+  };
+
+  Iterator begin() const {
+    print("begin()");
+    return Iterator(this, 2);
+  }
+
+  Iterator end() const {
+    print("end()");
+    return Iterator(this, -1);
+  }
+
+  void print(const char *msg, ...) const {
+    va_list args;
+    va_start(args, msg);
+    printf("[%s] ", name);
+    vprintf(msg, args);
+    printf("\n");
+    va_end(args);
+  }
+};
+
+int main() {
+  printf("do\n");
+#pragma omp parallel for collapse(2) num_threads(1)
+  for (int i = 0; i < 3; ++i)
+#pragma omp unroll partial(2)
+    for (Reporter c{"init-stmt"}; auto &&v : Reporter("range"))
+      printf("i=%d v=%d\n", i, v);
+  printf("done\n");
+  return EXIT_SUCCESS;
+}
+
+#endif /* HEADER */
+
+// CHECK:      do
+// CHECK-NEXT: [init-stmt] ctor
+// CHECK-NEXT: [range] ctor
+// CHECK-NEXT: [range] end()
+// CHECK-NEXT: [range] begin()
+// CHECK-NEXT: [range] begin()
+// CHECK-NEXT: [range] iterator distance: 3
+// CHECK-NEXT: [range] iterator advance: 0 += 0
+// CHECK-NEXT: [range] iterator move assign
+// CHECK-NEXT: [range] iterator deref: 0
+// CHECK-NEXT: i=0 v=0
+// CHECK-NEXT: [range] iterator dtor
+// CHECK-NEXT: [range] iterator advance: 0 += 1
+// CHECK-NEXT: [range] iterator move assign
+// CHECK-NEXT: [range] iterator deref: 1
+// CHECK-NEXT: i=0 v=1
+// CHECK-NEXT: [range] iterator dtor
+// CHECK-NEXT: [range] iterator advance: 0 += 2
+// CHECK-NEXT: [range] iterator move assign
+// CHECK-NEXT: [range] iterator deref: 2
+// CHECK-NEXT: i=0 v=2
+// CHECK-NEXT: [range] iterator dtor
+// CHECK-NEXT: [range] iterator advance: 0 += 0
+// CHECK-NEXT: [range] iterator move assign
+// CHECK-NEXT: [range] iterator deref: 0
+// CHECK-NEXT: i=1 v=0
+// CHECK-NEXT: [range] iterator dtor
+// CHECK-NEXT: [range] iterator advance: 0 += 1
+// CHECK-NEXT: [range] iterator move assign
+// CHECK-NEXT: [range] iterator deref: 1
+// CHECK-NEXT: i=1 v=1
+// CHECK-NEXT: [range] iterator dtor
+// CHECK-NEXT: [range] iterator advance: 0 += 2
+// CHECK-NEXT: [range] iterator move assign
+// CHECK-NEXT: [range] iterator deref: 2
+// CHECK-NEXT: i=1 v=2
+// CHECK-NEXT: [range] iterator dtor
+// CHECK-NEXT: [range] iterator advance: 0 += 0
+// CHECK-NEXT: [range] iterator move assign
+// CHECK-NEXT: [range] iterator deref: 0
+// CHECK-NEXT: i=2 v=0
+// CHECK-NEXT: [range] iterator dtor
+// CHECK-NEXT: [range] iterator advance: 0 += 1
+// CHECK-NEXT: [range] iterator move assign
+// CHECK-NEXT: [range] iterator deref: 1
+// CHECK-NEXT: i=2 v=1
+// CHECK-NEXT: [range] iterator dtor
+// CHECK-NEXT: [range] iterator advance: 0 += 2
+// CHECK-NEXT: [range] iterator move assign
+// CHECK-NEXT: [range] iterator deref: 2
+// CHECK-NEXT: i=2 v=2
+// CHECK-NEXT: [range] iterator dtor
+// CHECK-NEXT: [range] iterator dtor
+// CHECK-NEXT: [range] iterator dtor
+// CHECK-NEXT: [range] iterator dtor
+// CHECK-NEXT: [range] dtor
+// CHECK-NEXT: [init-stmt] dtor
+// CHECK-NEXT: done
diff --git a/openmp/runtime/test/transform/unroll/factor_parallel-wsloop-collapse-intfor.cpp b/openmp/runtime/test/transform/unroll/factor_parallel-wsloop-collapse-intfor.cpp
new file mode 100644
index 0000000..0a31f8d
--- /dev/null
+++ b/openmp/runtime/test/transform/unroll/factor_parallel-wsloop-collapse-intfor.cpp
@@ -0,0 +1,32 @@
+// RUN: %libomp-cxx-compile-and-run | FileCheck %s --match-full-lines
+
+#ifndef HEADER
+#define HEADER
+
+#include <cstdlib>
+#include <cstdio>
+
+int main() {
+  printf("do\n");
+#pragma omp parallel for collapse(2) num_threads(1)
+  for (int i = 0; i < 3; ++i)
+#pragma omp unroll partial(2)
+    for (int j = 0; j < 3; ++j)
+      printf("i=%d j=%d\n", i, j);
+  printf("done\n");
+  return EXIT_SUCCESS;
+}
+
+#endif /* HEADER */
+
+// CHECK:      do
+// CHECK-NEXT: i=0 j=0
+// CHECK-NEXT: i=0 j=1
+// CHECK-NEXT: i=0 j=2
+// CHECK-NEXT: i=1 j=0
+// CHECK-NEXT: i=1 j=1
+// CHECK-NEXT: i=1 j=2
+// CHECK-NEXT: i=2 j=0
+// CHECK-NEXT: i=2 j=1
+// CHECK-NEXT: i=2 j=2
+// CHECK-NEXT: done
diff --git a/openmp/runtime/test/transform/unroll/full_intfor.c b/openmp/runtime/test/transform/unroll/full_intfor.c
new file mode 100644
index 0000000..0814511
--- /dev/null
+++ b/openmp/runtime/test/transform/unroll/full_intfor.c
@@ -0,0 +1,25 @@
+// RUN: %libomp-compile-and-run | FileCheck %s --match-full-lines
+
+#ifndef HEADER
+#define HEADER
+
+#include <stdlib.h>
+#include <stdio.h>
+
+int main() {
+  printf("do\n");
+#pragma omp unroll full
+  for (int i = 7; i < 19; i += 3)
+    printf("i=%d\n", i);
+  printf("done\n");
+  return EXIT_SUCCESS;
+}
+
+#endif /* HEADER */
+
+// CHECK:      do
+// CHECK-NEXT: i=7
+// CHECK-NEXT: i=10
+// CHECK-NEXT: i=13
+// CHECK-NEXT: i=16
+// CHECK-NEXT: done
diff --git a/openmp/runtime/test/transform/unroll/heuristic_intfor.c b/openmp/runtime/test/transform/unroll/heuristic_intfor.c
new file mode 100644
index 0000000..b07bec7
--- /dev/null
+++ b/openmp/runtime/test/transform/unroll/heuristic_intfor.c
@@ -0,0 +1,25 @@
+// RUN: %libomp-compile-and-run | FileCheck %s --match-full-lines
+
+#ifndef HEADER
+#define HEADER
+
+#include <stdlib.h>
+#include <stdio.h>
+
+int main() {
+  printf("do\n");
+#pragma omp unroll
+  for (int i = 7; i < 19; i += 3)
+    printf("i=%d\n", i);
+  printf("done\n");
+  return EXIT_SUCCESS;
+}
+
+#endif /* HEADER */
+
+// CHECK:      do
+// CHECK-NEXT: i=7
+// CHECK-NEXT: i=10
+// CHECK-NEXT: i=13
+// CHECK-NEXT: i=16
+// CHECK-NEXT: done
diff --git a/openmp/runtime/test/transform/unroll/partial_intfor.c b/openmp/runtime/test/transform/unroll/partial_intfor.c
new file mode 100644
index 0000000..2ede94e
--- /dev/null
+++ b/openmp/runtime/test/transform/unroll/partial_intfor.c
@@ -0,0 +1,25 @@
+// RUN: %libomp-compile-and-run | FileCheck %s --match-full-lines
+
+#ifndef HEADER
+#define HEADER
+
+#include <stdlib.h>
+#include <stdio.h>
+
+int main() {
+  printf("do\n");
+#pragma omp unroll partial
+  for (int i = 7; i < 19; i += 3)
+    printf("i=%d\n", i);
+  printf("done\n");
+  return EXIT_SUCCESS;
+}
+
+#endif /* HEADER */
+
+// CHECK:      do
+// CHECK-NEXT: i=7
+// CHECK-NEXT: i=10
+// CHECK-NEXT: i=13
+// CHECK-NEXT: i=16
+// CHECK-NEXT: done