[libc] Enable missing memory tests on the GPU (#68111)

Summary:
There were a few tests that weren't enabled on the GPU. This is because
the logic caused them to be skipped as we don't use CPU featured on the
host. This also disables the logic making multiple versions of the
memory functions.

Author: jhuber6

libc/cmake/modules/LLVMLibCCheckCpuFeatures.cmake

@@ -22,10 +22,6 @@ list(SORT ALL_CPU_FEATURES)
 #   <list of cpu features>
 # )
 function(cpu_supports output_var features)
-  if(LIBC_TARGET_ARCHITECTURE_IS_GPU)
-    unset(${output_var} PARENT_SCOPE)
-    return()
-  endif()
   _intersection(var "${LIBC_CPU_FEATURES}" "${features}")
   if("${var}" STREQUAL "${features}")
     set(${output_var} TRUE PARENT_SCOPE)

libc/src/string/CMakeLists.txt

@@ -498,6 +498,8 @@ if(${LIBC_TARGET_ARCHITECTURE_IS_X86})
   add_bcmp(bcmp_x86_64_opt_avx512 COMPILE_OPTIONS -march=skylake-avx512 REQUIRE AVX512BW)
   add_bcmp(bcmp_opt_host          COMPILE_OPTIONS ${LIBC_COMPILE_OPTIONS_NATIVE})
   add_bcmp(bcmp)
+elseif(LIBC_TARGET_ARCHITECTURE_IS_GPU)
+  add_bcmp(bcmp)
 else()
   add_bcmp(bcmp_opt_host          COMPILE_OPTIONS ${LIBC_COMPILE_OPTIONS_NATIVE})
   add_bcmp(bcmp)
@@ -525,6 +527,8 @@ if(${LIBC_TARGET_ARCHITECTURE_IS_X86})
   add_bzero(bzero_x86_64_opt_avx512 COMPILE_OPTIONS -march=skylake-avx512 REQUIRE AVX512F)
   add_bzero(bzero_opt_host          COMPILE_OPTIONS ${LIBC_COMPILE_OPTIONS_NATIVE})
   add_bzero(bzero)
+elseif(LIBC_TARGET_ARCHITECTURE_IS_GPU)
+  add_bzero(bzero)
 else()
   add_bzero(bzero_opt_host          COMPILE_OPTIONS ${LIBC_COMPILE_OPTIONS_NATIVE})
   add_bzero(bzero)
@@ -555,6 +559,8 @@ if(${LIBC_TARGET_ARCHITECTURE_IS_X86})
 elseif(${LIBC_TARGET_ARCHITECTURE_IS_AARCH64})
   add_memcmp(memcmp_opt_host          COMPILE_OPTIONS ${LIBC_COMPILE_OPTIONS_NATIVE})
   add_memcmp(memcmp)
+elseif(LIBC_TARGET_ARCHITECTURE_IS_GPU)
+  add_memcmp(memcmp)
 else()
   add_memcmp(memcmp_opt_host          COMPILE_OPTIONS ${LIBC_COMPILE_OPTIONS_NATIVE})
   add_memcmp(memcmp)
@@ -589,6 +595,8 @@ elseif(${LIBC_TARGET_ARCHITECTURE_IS_AARCH64})
   add_memcpy(memcpy_opt_host          COMPILE_OPTIONS ${LIBC_COMPILE_OPTIONS_NATIVE}
                                       MLLVM_COMPILE_OPTIONS "-tail-merge-threshold=0")
   add_memcpy(memcpy                   MLLVM_COMPILE_OPTIONS "-tail-merge-threshold=0")
+elseif(LIBC_TARGET_ARCHITECTURE_IS_GPU)
+  add_memcpy(memcpy)
 else()
   add_memcpy(memcpy_opt_host          COMPILE_OPTIONS ${LIBC_COMPILE_OPTIONS_NATIVE})
   add_memcpy(memcpy)
@@ -621,6 +629,8 @@ elseif(${LIBC_TARGET_ARCHITECTURE_IS_AARCH64})
   add_memmove(memmove_opt_host          COMPILE_OPTIONS ${LIBC_COMPILE_OPTIONS_NATIVE}
                                         MLLVM_COMPILE_OPTIONS "-tail-merge-threshold=0")
   add_memmove(memmove                   MLLVM_COMPILE_OPTIONS "-tail-merge-threshold=0")
+elseif(LIBC_TARGET_ARCHITECTURE_IS_GPU)
+  add_memmove(memmove)
 else()
   add_memmove(memmove_opt_host          COMPILE_OPTIONS ${LIBC_COMPILE_OPTIONS_NATIVE})
   add_memmove(memmove)
@@ -653,6 +663,8 @@ elseif(${LIBC_TARGET_ARCHITECTURE_IS_AARCH64})
   add_memset(memset_opt_host          COMPILE_OPTIONS ${LIBC_COMPILE_OPTIONS_NATIVE}
                                       MLLVM_COMPILE_OPTIONS "-tail-merge-threshold=0")
   add_memset(memset                   MLLVM_COMPILE_OPTIONS "-tail-merge-threshold=0")
+elseif(LIBC_TARGET_ARCHITECTURE_IS_GPU)
+  add_memset(memset)
 else()
   add_memset(memset_opt_host          COMPILE_OPTIONS ${LIBC_COMPILE_OPTIONS_NATIVE})
   add_memset(memset)

libc/test/src/string/CMakeLists.txt

@@ -425,8 +425,11 @@ function(add_libc_multi_impl_test name)
     get_target_property(required_cpu_features ${fq_config_name} REQUIRE_CPU_FEATURES)
     cpu_supports(can_run "${required_cpu_features}")
     if(can_run)
+      string(FIND ${fq_config_name} "." last_dot_loc REVERSE)
+      math(EXPR name_loc "${last_dot_loc} + 1")
+      string(SUBSTRING ${fq_config_name} ${name_loc} -1 target_name)
       add_libc_test(
-        ${fq_config_name}_test
+        ${target_name}_test
         SUITE
           libc-string-tests
         COMPILE_OPTIONS