[NFC][Driver][HIP] Fix mixing amdgcnspirv and gfxXXX via --offload-arch (#133024)

Due to `amdgcnspirv` piggybacking on the HIPAMDToolchain, it loses its
immediately apparent SPIR-Vness, which makes the Driver want to go all
the way to Assembly emmission. This was problematic as we were trying to
`llvm-link` SPIR-V, before trying to translate it. This patch ensures
that we do the right thing and stop at bitcode emission if we are mixing
`amdgcnspirv` and concrete targets.

Author: AlexVlx

clang/lib/Driver/Driver.cpp

@@ -3750,9 +3750,12 @@ class OffloadingActionBuilder final {
             // compiler phases, including backend and assemble phases.
             ActionList AL;
             Action *BackendAction = nullptr;
-            if (ToolChains.front()->getTriple().isSPIRV()) {
+            if (ToolChains.front()->getTriple().isSPIRV() ||
+                (ToolChains.front()->getTriple().isAMDGCN() &&
+                 GpuArchList[I] == StringRef("amdgcnspirv"))) {
               // Emit LLVM bitcode for SPIR-V targets. SPIR-V device tool chain
-              // (HIPSPVToolChain) runs post-link LLVM IR passes.
+              // (HIPSPVToolChain or HIPAMDToolChain) runs post-link LLVM IR
+              // passes.
               types::ID Output = Args.hasArg(options::OPT_S)
                                      ? types::TY_LLVM_IR
                                      : types::TY_LLVM_BC;

clang/test/Driver/hip-toolchain-no-rdc.hip

@@ -187,8 +187,8 @@
 // Check mixed AMDGCNSPIRV and concrete GPU arch.
 //
 
-// AMDGCNSPIRV: "-cc1" "-triple" "spirv64-amd-amdhsa" {{.*}}"-emit-obj" {{.*}} "-o" "[[AMDGCNSPV_OBJ:.*o]]"
-// AMDGCNSPIRV: {{".*llvm-link.*"}} "-o" "[[AMDGCNSPV_TMP:.*out]]" "[[AMDGCNSPV_OBJ]]"
+// AMDGCNSPIRV: "-cc1" "-triple" "spirv64-amd-amdhsa" {{.*}}"-emit-llvm-bc" {{.*}} "-o" "[[AMDGCNSPV_BC:.*bc]]"
+// AMDGCNSPIRV: {{".*llvm-link.*"}} "-o" "[[AMDGCNSPV_TMP:.*out]]" "[[AMDGCNSPV_BC]]"
 // AMDGCNSPIRV: {{".*llvm-spirv.*"}} "--spirv-max-version=1.6" "--spirv-ext=+all" {{.*}} "[[AMDGCNSPV_TMP]]" {{.*}}"-o" "[[AMDGCNSPV_CO:.*out]]"
 // AMDGCNSPIRV: "-cc1" "-triple" "amdgcn-amd-amdhsa" {{.*}}"-emit-obj" {{.*}}"-target-cpu" "gfx900"{{.*}} "-o" "[[GFX900_OBJ:.*o]]"
 // AMDGCNSPIRV: {{".*lld.*"}} {{.*}}"-plugin-opt=mcpu=gfx900" {{.*}} "-o" "[[GFX900_CO:.*out]]" {{.*}}"[[GFX900_OBJ]]"