subgroups: Fix setting cl_halfs and progress check. (#1278)

* subgroups: Fix setting cl_halfs and progress check.

cl_float testing uses set_value such that a generated cl_ulong of 1 is
stored as 1.0F in a logical sense. However, cl_half values aren't
intrinsic to C++ and generated cl_ulongs less than 1024 in particular
are interpreted bitwise as subnormals. The test fails on compute devices
lacking subnormal support. Perform the logical conversion to cl_half.

Fix independent forward progress check.

* subgroups_half: Address review comments

* subgroups_half: Formatting fixes required by check-format

* subgroups_half: Modified to query and use rounding mode supported by device

Co-authored-by: spauls <spauls@qti.qualcomm.com>

test_conformance/subgroups/main.cpp

@@ -19,8 +19,10 @@
 #include <string.h>
 #include "procs.h"
 #include "harness/testHarness.h"
+#include "CL/cl_half.h"
 
 MTdata gMTdata;
+cl_half_rounding_mode g_rounding_mode;
 
 test_definition test_list[] = {
     ADD_TEST_VERSION(sub_group_info_ext, Version(2, 0)),
@@ -66,6 +68,22 @@ static test_status InitCL(cl_device_id device)
             ret = TEST_SKIP;
         }
     }
+    // Determine the rounding mode to be used in float to half conversions in
+    // init and reference code
+    const cl_device_fp_config fpConfig = get_default_rounding_mode(device);
+
+    if (fpConfig == CL_FP_ROUND_TO_NEAREST)
+    {
+        g_rounding_mode = CL_HALF_RTE;
+    }
+    else if (fpConfig == CL_FP_ROUND_TO_ZERO && gIsEmbedded)
+    {
+        g_rounding_mode = CL_HALF_RTZ;
+    }
+    else
+    {
+        assert(false && "Unreachable");
+    }
     return ret;
 }
 

test_conformance/subgroups/subgroup_common_templates.h

@@ -301,7 +301,7 @@ static float to_float(subgroups::cl_half x) { return cl_half_to_float(x.data); }
 static subgroups::cl_half to_half(float x)
 {
     subgroups::cl_half value;
-    value.data = cl_half_from_float(x, CL_HALF_RTE);
+    value.data = cl_half_from_float(x, g_rounding_mode);
     return value;
 }
 

test_conformance/subgroups/subhelpers.h

@@ -28,6 +28,7 @@
 #define NR_OF_ACTIVE_WORK_ITEMS 4
 
 extern MTdata gMTdata;
+extern cl_half_rounding_mode g_rounding_mode;
 
 struct WorkGroupParams
 {
@@ -1080,7 +1081,7 @@ template <typename Ty>
 typename std::enable_if<TypeManager<Ty>::is_sb_scalar_type::value>::type
 set_value(Ty &lhs, const cl_ulong &rhs)
 {
-    lhs.data = rhs;
+    lhs.data = cl_half_from_float(static_cast<cl_float>(rhs), g_rounding_mode);
 }
 
 // compare for common vectors

test_conformance/subgroups/test_ifp.cpp

@@ -360,17 +360,21 @@ int test_ifp_ext(cl_device_id device, cl_context context,
     }
     // ifp only in subgroup functions tests:
     test_status error;
-    error = checkIFPSupport(device, ifpSupport);
+    auto device_cl_version = get_device_cl_version(device);
-    if (error != TEST_PASS)
+    if (device_cl_version >= Version(2, 1))
     {
-        return error;
+        error = checkIFPSupport(device, ifpSupport);
-    }
+        if (error != TEST_PASS)
-    if (ifpSupport == false)
+        {
-    {
+            return error;
-        log_info(
+        }
-            "Error reason: the extension cl_khr_subgroups requires that "
+        if (ifpSupport == false)
-            "Independed forward progress has to be supported by device.\n");
+        {
-        return TEST_FAIL;
+            log_info(
+                "Error reason: the extension cl_khr_subgroups requires that "
+                "Independed forward progress has to be supported by device.\n");
+            return TEST_FAIL;
+        }
     }
     return test_ifp(device, context, queue, num_elements, false);
-}
+}