[SystemZ] Automatically detect zEC12 and z196 hosts

As on other hosts, the CPU identification instruction is priveleged,
so we need to look through /proc/cpuinfo.  I copied the PowerPC way of
handling "generic".

Several tests were implicitly assuming z10 and so failed on z196.

llvm-svn: 193742

2 files changed, 9 insertions, 3 deletions

diff --git a/llvm/lib/Target/SystemZ/SystemZProcessors.td b/llvm/lib/Target/SystemZ/SystemZProcessors.td
index 00d4338af55..f241fb0c222 100644
--- a/llvm/lib/Target/SystemZ/SystemZProcessors.td
+++ b/llvm/lib/Target/SystemZ/SystemZProcessors.td
@@ -36,8 +36,9 @@ def FeatureFPExtension : SystemZFeature<
   "Assume that the floating-point extension facility is installed"
 >;
 
-def : Processor<"z10",   NoItineraries, []>;
-def : Processor<"z196",  NoItineraries,
+def : Processor<"generic", NoItineraries, []>;
+def : Processor<"z10", NoItineraries, []>;
+def : Processor<"z196", NoItineraries,
                 [FeatureDistinctOps, FeatureLoadStoreOnCond, FeatureHighWord,
                  FeatureFPExtension]>;
 def : Processor<"zEC12", NoItineraries,
diff --git a/llvm/lib/Target/SystemZ/SystemZSubtarget.cpp b/llvm/lib/Target/SystemZ/SystemZSubtarget.cpp
index b6a63923cf5..474192099f2 100644
--- a/llvm/lib/Target/SystemZ/SystemZSubtarget.cpp
+++ b/llvm/lib/Target/SystemZ/SystemZSubtarget.cpp
@@ -9,6 +9,7 @@
 
 #include "SystemZSubtarget.h"
 #include "llvm/IR/GlobalValue.h"
+#include "llvm/Support/Host.h"
 #include "MCTargetDesc/SystemZMCTargetDesc.h"
 
 #define GET_SUBTARGETINFO_TARGET_DESC
@@ -25,7 +26,11 @@ SystemZSubtarget::SystemZSubtarget(const std::string &TT,
     TargetTriple(TT) {
   std::string CPUName = CPU;
   if (CPUName.empty())
-    CPUName = "z10";
+    CPUName = "generic";
+#if defined(__linux__) && defined(__s390x__)
+  if (CPUName == "generic")
+    CPUName = sys::getHostCPUName();
+#endif
 
   // Parse features string.
   ParseSubtargetFeatures(CPUName, FS);