[Driver][SYCL] Improve diagnostic behaviors for intel_gpu targets

When using multiple targets, like
-fsycl-targets=intel_gpu_pvc,intel_gpu_bdw, we were emitting a
diagnostic that the latter value was being ignored as the values were
similar.  This is not a correct diagnostic, as the values have identical
triples, but not an identical arch target.

Update how these diagnostics are produced, depending on using the old or
the new offloading model.

Author: mdtoguchi

clang/lib/Driver/Driver.cpp

@@ -1396,14 +1396,28 @@ void Driver::CreateOffloadingDeviceToolChains(Compilation &C,
           } else
             TT = getSYCLDeviceTriple(Triple);
 
-          std::string NormalizedName = TT.normalize();
+          // For the new offloading model, we only want a single triple entry
+          // for each target, even if we have multiple intel_gpu* entries.  We
+          // will track triples for new model and unique strings for the old
+          // model.
+          std::string NormalizedName;
+          bool UseNewOffload =
+              (C.getArgs().hasFlag(options::OPT_offload_new_driver,
+                                   options::OPT_no_offload_new_driver, false));
+          NormalizedName = UseNewOffload
+                               ? TT.normalize()
+                               : getSYCLDeviceTriple(Triple).normalize();
 
           auto [TripleIt, Inserted] =
               FoundNormalizedTriples.try_emplace(NormalizedName, Triple);
 
           if (!Inserted) {
-            Diag(clang::diag::warn_drv_sycl_offload_target_duplicate)
-                << Triple << TripleIt->second;
+            // Only emit the diagnostic of duplicate targets with the new
+            // offloading model only when the found triple matches.  For the
+            // old model, we always emit the diagnostic.
+            if (!UseNewOffload || (UseNewOffload && Triple == TripleIt->second))
+              Diag(clang::diag::warn_drv_sycl_offload_target_duplicate)
+                  << Triple << TripleIt->second;
             continue;
           }
 

clang/test/Driver/sycl-offload-old-model.c

@@ -76,6 +76,16 @@
 // RUN:   | FileCheck -check-prefix=CHK-DUPLICATES %s
 // CHK-DUPLICATES: warning: SYCL offloading target 'spir64-unknown-unknown' is similar to target 'spir64-unknown-unknown' already specified; will be ignored
 
+// RUN:   %clang -### -ccc-print-phases -fsycl --no-offload-new-driver -fsycl-targets=intel_gpu_pvc,intel_gpu_pvc  %s 2>&1 \
+// RUN:   | FileCheck -check-prefix=CHK-DUPLICATES-GPU %s
+// CHK-DUPLICATES-GPU: warning: SYCL offloading target 'intel_gpu_pvc' is similar to target 'intel_gpu_pvc' already specified; will be ignored
+
+/// No duplicate warning should be emitted for 'like' triples but different
+/// arch targets.
+// RUN:   %clang -### -ccc-print-phases -fsycl --no-offload-new-driver -fsycl-targets=intel_gpu_pvc,intel_gpu_bdw  %s 2>&1 \
+// RUN:   | FileCheck -check-prefix=CHK-DIFF-GPU %s
+// CHK-DIFF-GPU-NOT: warning: SYCL offloading target 'intel_gpu_bdw' is similar to target 'intel_gpu_pvc' already specified; will be ignored
+
 /// ###########################################################################
 
 /// Check -Xsycl-target-frontend triggers error when multiple triples are used.

clang/test/Driver/sycl-offload.c

@@ -83,6 +83,16 @@
 // RUN:   | FileCheck -check-prefix=CHK-DUPLICATES %s
 // CHK-DUPLICATES: warning: SYCL offloading target 'spir64-unknown-unknown' is similar to target 'spir64-unknown-unknown' already specified; will be ignored
 
+// RUN:   %clang -### -ccc-print-phases -fsycl --offload-new-driver -fsycl-targets=intel_gpu_pvc,intel_gpu_pvc  %s 2>&1 \
+// RUN:   | FileCheck -check-prefix=CHK-DUPLICATES-GPU %s
+// CHK-DUPLICATES-GPU: warning: SYCL offloading target 'intel_gpu_pvc' is similar to target 'intel_gpu_pvc' already specified; will be ignored
+
+/// No duplicate warning should be emitted for 'like' triples but different
+/// arch targets.
+// RUN:   %clang -### -ccc-print-phases -fsycl --offload-new-driver -fsycl-targets=intel_gpu_pvc,intel_gpu_bdw  %s 2>&1 \
+// RUN:   | FileCheck -check-prefix=CHK-DIFF-GPU %s
+// CHK-DIFF-GPU-NOT: warning: SYCL offloading target 'intel_gpu_bdw' is similar to target 'intel_gpu_pvc' already specified; will be ignored
+
 /// ###########################################################################
 
 /// Check -Xsycl-target-frontend triggers error when multiple triples are used.