microarchitectures: fix ppc flags for clang (#14196)

lib/spack/llnl/util/cpu/microarchitectures.json

@@ -994,8 +994,7 @@
         },
         "clang": {
           "versions": ":",
-          "family": "ppc64",
-          "flags": "-march={family} -mcpu=generic"
+          "flags": "-mcpu={name} -mtune={name}"
         }
       }
     },
@@ -1011,9 +1010,7 @@
         },
         "clang": {
           "versions": "3.9:",
-          "family": "ppc64",
-          "name": "pwr7",
-          "flags": "-march={family} -mcpu={name}"
+          "flags": "-mcpu={name} -mtune={name}"
         }
       }
     },
@@ -1036,9 +1033,7 @@
         ],
         "clang": {
           "versions": "3.9:",
-          "family": "ppc64",
-          "name": "pwr8",
-          "flags": "-march={family} -mcpu={name}"
+          "flags": "-mcpu={name} -mtune={name}"
         }
       }
     },
@@ -1054,9 +1049,7 @@
         },
         "clang": {
           "versions": "3.9:",
-          "family": "ppc64",
-          "name": "pwr9",
-          "flags": "-march={family} -mcpu={name}"
+          "flags": "-mcpu={name} -mtune={name}"
         }
       }
     },
@@ -1072,8 +1065,7 @@
         },
         "clang": {
           "versions": ":",
-          "family": "ppc64le",
-          "flags": "-march={family} -mcpu=generic"
+          "flags": "-mcpu={name} -mtune={name}"
         }
       }
     },
@@ -1099,8 +1091,8 @@
         "clang": {
           "versions": "3.9:",
           "family": "ppc64le",
-          "name": "pwr8",
-          "flags": "-march={family} -mcpu={name}"
+          "name": "power8",
+          "flags": "-mcpu={name} -mtune={name}"
         }
       }
     },
@@ -1118,8 +1110,8 @@
         "clang": {
           "versions": "3.9:",
           "family": "ppc64le",
-          "name": "pwr9",
-          "flags": "-march={family} -mcpu={name}"
+          "name": "power9",
+          "flags": "-mcpu={name} -mtune={name}"
         }
       }
     },

lib/spack/spack/test/llnl/util/cpu.py

@@ -218,7 +218,7 @@ def test_target_json_schema():
     ('icelake', 'clang', '8.0.0',
      '-march=icelake-client -mtune=icelake-client'),
     ('zen2', 'clang', '9.0.0', '-march=znver2 -mtune=znver2'),
-    ('power9le', 'clang', '8.0.0', '-march=ppc64le -mcpu=pwr9'),
+    ('power9le', 'clang', '8.0.0', '-mcpu=power9 -mtune=power9'),
     ('thunderx2', 'clang', '6.0.0', '-mcpu=thunderx2t99'),
     # Test Intel on Intel CPUs
     ('sandybridge', 'intel', '17.0.2', '-march=corei7-avx -mtune=corei7-avx'),