[clang] [llvm] [NFC][OpenMP] Add tests for mapping pointers and their dereferences. (PR #146934)

[Abhinav Gaba via llvm-commits]

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@@ -0,0 +1,83 @@
+// RUN: %libomptarget-compilexx-run-and-check-generic
+
+#include <omp.h>
+#include <stdio.h>
+
+int x[10];
+
+void f1() {
+  int *p;
+  p = &x[0];
+  p[0] = 111;
+  p[1] = 222;
+  p[2] = 333;
+  p[3] = 444;
+
+#pragma omp target enter data map(to : p)
+#pragma omp target enter data map(to : p[0 : 5])
+
+  int **p_mappedptr = (int **)omp_get_mapped_ptr(&p, omp_get_default_device());
+  int *x0_mappedptr =
+      (int *)omp_get_mapped_ptr(&x[0], omp_get_default_device());
+  int *x0_hostaddr = &x[0];
+
+  printf("p_mappedptr %s null\n", p_mappedptr == (int **)NULL ? "==" : "!=");
+  printf("x0_mappedptr %s null\n", x0_mappedptr == (int *)NULL ? "==" : "!=");
+
+// CHECK: p_mappedptr != null
+// CHECK: x0_mappedptr != null
+
+// p is predetermined firstprivate, so its address will be different from
+// the mapped address for this construct. So, any changes to p within the
+// region will not be visible after the construct.
+#pragma omp target map(p[0]) map(to : p_mappedptr, x0_mappedptr, x0_hostaddr)
+  {
+    printf("%d %d %d %d\n", p[0], p_mappedptr == &p, x0_mappedptr == &p[0],
+           x0_hostaddr == &p[0]);
+    // CHECK:    111 0 1 0
+    p++;
+  }
+
+// For the remaining constructs, p is not firstprivate, so its address will
+// be the same as the mapped address, and changes to p will be visible to any
+// subsequent regions.
+#pragma omp target map(to : p[0], p)                                           \
+    map(to : p_mappedptr, x0_mappedptr, x0_hostaddr)
+  {
+    printf("%d %d %d %d\n", p[0], p_mappedptr == &p, x0_mappedptr == &p[0],
+           x0_hostaddr == &p[0]);
+    // EXPECTED: 111 1 1 0
+    // CHECK:    111 0 1 0
+    p++;
+  }
+
+#pragma omp target map(to : p, p[0])                                           \
+    map(to : p_mappedptr, x0_mappedptr, x0_hostaddr)
+  {
+    printf("%d %d %d %d\n", p[0], p_mappedptr == &p, x0_mappedptr == &p[-1],
+           x0_hostaddr == &p[-1]);
+    // EXPECTED: 222 1 1 0
+    // CHECK:    111 0 0 0
----------------
abhinavgaba wrote:

I kept the expected output here as a comment, instead of using that for CHECKs, so that we can track the current status of the compiler/runtime, instead of marking this as UNSUPPORTED/XFAIL. I can change that and mark these as XFAIL if that's preferable.

https://github.com/llvm/llvm-project/pull/146934