[OpenMP][DeviceRTL] Fix the issue that multiple calls to `omp_get_wtime` is optimized out by mistake

Multiple calls to `omp_get_wtime` could be optimized out due to the function
is mistakenly marked as `readnone`. This patch fixes the issue, and also add the
support to run optimization on `libomptarget` tests.

Reviewed By: jdoerfert

Differential Revision: https://reviews.llvm.org/D130179

3 files changed, 78 insertions, 2 deletions

diff --git a/openmp/libomptarget/DeviceRTL/src/Misc.cpp b/openmp/libomptarget/DeviceRTL/src/Misc.cpp
index 554a13a..7166925 100644
--- a/openmp/libomptarget/DeviceRTL/src/Misc.cpp
+++ b/openmp/libomptarget/DeviceRTL/src/Misc.cpp
@@ -52,7 +52,7 @@ double getWTick() {
 
 double getWTime() {
   unsigned long long nsecs;
-  asm("mov.u64  %0, %%globaltimer;" : "=l"(nsecs));
+  asm volatile("mov.u64  %0, %%globaltimer;" : "=l"(nsecs));
   return (double)nsecs * getWTick();
 }
 
diff --git a/openmp/libomptarget/test/lit.cfg b/openmp/libomptarget/test/lit.cfg
index 5436d32..f0eadea 100644
--- a/openmp/libomptarget/test/lit.cfg
+++ b/openmp/libomptarget/test/lit.cfg
@@ -128,7 +128,7 @@ for libomptarget_target in config.libomptarget_all_targets:
     # Is this target in the current system? If so create a compile, run and test
     # command. Otherwise create command that return false.
     if libomptarget_target == config.libomptarget_current_target:
-        config.substitutions.append(("%libomptarget-compilexx-run-and-check-generic", 
+        config.substitutions.append(("%libomptarget-compilexx-run-and-check-generic",
             "%libomptarget-compilexx-run-and-check-" + libomptarget_target))
         config.substitutions.append(("%libomptarget-compile-run-and-check-generic",
             "%libomptarget-compile-run-and-check-" + libomptarget_target))
@@ -140,6 +140,18 @@ for libomptarget_target in config.libomptarget_all_targets:
             "%libomptarget-compilexx-" + libomptarget_target))
         config.substitutions.append(("%libomptarget-compile-generic",
             "%libomptarget-compile-" + libomptarget_target))
+        config.substitutions.append(("%libomptarget-compileoptxx-run-and-check-generic",
+            "%libomptarget-compileoptxx-run-and-check-" + libomptarget_target))
+        config.substitutions.append(("%libomptarget-compileopt-run-and-check-generic",
+            "%libomptarget-compileopt-run-and-check-" + libomptarget_target))
+        config.substitutions.append(("%libomptarget-compileoptxx-and-run-generic",
+            "%libomptarget-compileoptxx-and-run-" + libomptarget_target))
+        config.substitutions.append(("%libomptarget-compileopt-and-run-generic",
+            "%libomptarget-compileopt-and-run-" + libomptarget_target))
+        config.substitutions.append(("%libomptarget-compileoptxx-generic",
+            "%libomptarget-compileoptxx-" + libomptarget_target))
+        config.substitutions.append(("%libomptarget-compileopt-generic",
+            "%libomptarget-compileopt-" + libomptarget_target))
         config.substitutions.append(("%libomptarget-run-generic",
             "%libomptarget-run-" + libomptarget_target))
         config.substitutions.append(("%libomptarget-run-fail-generic",
@@ -174,6 +186,28 @@ for libomptarget_target in config.libomptarget_all_targets:
         config.substitutions.append(("%libomptarget-compile-" + \
             libomptarget_target, \
             "%clang-" + libomptarget_target + " %s -o %t"))
+        config.substitutions.append(("%libomptarget-compileoptxx-run-and-check-" + \
+            libomptarget_target, \
+            "%libomptarget-compileoptxx-and-run-" + libomptarget_target + \
+            " | " + config.libomptarget_filecheck + " %s"))
+        config.substitutions.append(("%libomptarget-compileopt-run-and-check-" + \
+            libomptarget_target, \
+            "%libomptarget-compileopt-and-run-" + libomptarget_target + \
+            " | " + config.libomptarget_filecheck + " %s"))
+        config.substitutions.append(("%libomptarget-compileoptxx-and-run-" + \
+            libomptarget_target, \
+            "%libomptarget-compileoptxx-" + libomptarget_target + " && " + \
+            "%libomptarget-run-" + libomptarget_target))
+        config.substitutions.append(("%libomptarget-compileopt-and-run-" + \
+            libomptarget_target, \
+            "%libomptarget-compileopt-" + libomptarget_target + " && " + \
+            "%libomptarget-run-" + libomptarget_target))
+        config.substitutions.append(("%libomptarget-compileoptxx-" + \
+            libomptarget_target, \
+            "%clangxx-" + libomptarget_target + " -O3 %s -o %t"))
+        config.substitutions.append(("%libomptarget-compileopt-" + \
+            libomptarget_target, \
+            "%clang-" + libomptarget_target + " -O3 %s -o %t"))
         config.substitutions.append(("%libomptarget-run-" + \
             libomptarget_target, \
             "%t"))
@@ -207,6 +241,24 @@ for libomptarget_target in config.libomptarget_all_targets:
         config.substitutions.append(("%libomptarget-compile-" + \
             libomptarget_target, \
             "echo ignored-command"))
+        config.substitutions.append(("%libomptarget-compileopt-run-and-check-" + \
+            libomptarget_target, \
+            "echo ignored-command"))
+        config.substitutions.append(("%libomptarget-compileoptxx-run-and-check-" + \
+            libomptarget_target, \
+            "echo ignored-command"))
+        config.substitutions.append(("%libomptarget-compileopt-and-run-" + \
+            libomptarget_target, \
+            "echo ignored-command"))
+        config.substitutions.append(("%libomptarget-compileoptxx-and-run-" + \
+            libomptarget_target, \
+            "echo ignored-command"))
+        config.substitutions.append(("%libomptarget-compileoptxx-" + \
+            libomptarget_target, \
+            "echo ignored-command"))
+        config.substitutions.append(("%libomptarget-compileopt-" + \
+            libomptarget_target, \
+            "echo ignored-command"))
         config.substitutions.append(("%libomptarget-run-" + \
             libomptarget_target, \
             "echo ignored-command"))
diff --git a/openmp/libomptarget/test/offloading/wtime.c b/openmp/libomptarget/test/offloading/wtime.c
new file mode 100644
index 0000000..bc2e1f7
--- /dev/null
+++ b/openmp/libomptarget/test/offloading/wtime.c
@@ -0,0 +1,24 @@
+// RUN: %libomptarget-compileopt-run-and-check-generic
+
+// UNSUPPORTED: amdgcn-amd-amdhsa
+// UNSUPPORTED: amdgcn-amd-amdhsa-oldDriver
+// UNSUPPORTED: amdgcn-amd-amdhsa-LTO
+
+#include <omp.h>
+#include <stdio.h>
+
+int main(int argc, char *argv[]) {
+  int data[1024];
+#pragma omp target
+  {
+    double start = omp_get_wtime();
+    for (int i = 0; i < 1024; ++i)
+      data[i] = i;
+    double end = omp_get_wtime();
+    double duration = end - start;
+    printf("duration: %lfs\n", duration);
+  }
+  return 0;
+}
+
+// CHECK: duration: [1-9]+