src/cpu/x86/vm/vm_version_x86.cpp

@@ -467,10 +467,11 @@
       __ addptr(rsp, 64);
 #endif // _LP64
       __ evmovdqul(xmm7, Address(rsp, 0), Assembler::AVX_512bit);
       __ addptr(rsp, 64);
 #endif // _WINDOWS
+      __ vzeroupper();
       VM_Version::clean_cpuFeatures();
       UseAVX = saved_useavx;
       UseSSE = saved_usesse;
       __ jmp(wrapup);
     }

@@ -496,10 +497,11 @@
     __ addptr(rsp, 32);
 #endif // _LP64
     __ vmovdqu(xmm7, Address(rsp, 0));
     __ addptr(rsp, 32);
 #endif // _WINDOWS
+    __ vzeroupper();
     VM_Version::clean_cpuFeatures();
     UseAVX = saved_useavx;
     UseSSE = saved_usesse;
 
     __ bind(wrapup);

@@ -617,21 +619,31 @@
   }
 
   if (UseAVX < 2)
     _features &= ~CPU_AVX2;
 
-  if (UseAVX < 1)
+  if (UseAVX < 1) {
     _features &= ~CPU_AVX;
+    _features &= ~CPU_VZEROUPPER;
+  }
 
   if (!UseAES && !FLAG_IS_DEFAULT(UseAES))
     _features &= ~CPU_AES;
 
   if (logical_processors_per_package() == 1) {
     // HT processor could be installed on a system which doesn't support HT.
     _features &= ~CPU_HT;
   }
 
+  if( is_intel() ) { // Intel cpus specific settings
+    if ((cpu_family() == 0x06) &&
+        ((extended_cpu_model() == 0x57) ||   // Xeon Phi 3200/5200/7200
+        (extended_cpu_model() == 0x85))) {  // Future Xeon Phi
+      _features &= ~CPU_VZEROUPPER;
+    }
+  }
+
   char buf[256];
   jio_snprintf(buf, sizeof(buf), "(%u cores per cpu, %u threads per core) family %d model %d stepping %d%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s",
                cores_per_cpu(), threads_per_core(),
                cpu_family(), _model, _stepping,
                (supports_cmov() ? ", cmov" : ""),

@@ -916,20 +928,40 @@
   if (MaxVectorSize > 0) {
     if (!is_power_of_2(MaxVectorSize)) {
       warning("MaxVectorSize must be a power of 2");
       FLAG_SET_DEFAULT(MaxVectorSize, 64);
     }
-    if (MaxVectorSize > 64) {
-      FLAG_SET_DEFAULT(MaxVectorSize, 64);
+    if (UseSSE < 2) {
+      // Vectors (in XMM) are only supported with SSE2+
+      if (MaxVectorSize > 0) {
+        if (!FLAG_IS_DEFAULT(MaxVectorSize))
+          warning("MaxVectorSize must be 0");
+        FLAG_SET_DEFAULT(MaxVectorSize, 0);
     }
-    if (MaxVectorSize > 16 && (UseAVX == 0 || !os_supports_avx_vectors())) {
+    }
+    else if (UseAVX == 0 || !os_supports_avx_vectors()) {
       // 32 bytes vectors (in YMM) are only supported with AVX+
+      if (MaxVectorSize > 16) {
+        if (!FLAG_IS_DEFAULT(MaxVectorSize))
+          warning("MaxVectorSize must be <= 16");
       FLAG_SET_DEFAULT(MaxVectorSize, 16);
     }
-    if (UseSSE < 2) {
-      // Vectors (in XMM) are only supported with SSE2+
-      FLAG_SET_DEFAULT(MaxVectorSize, 0);
+    }
+    else if (UseAVX == 1 || UseAVX == 2) {
+      // 64 bytes vectors (in ZMM) are only supported with AVX 3
+      if (MaxVectorSize > 32) {
+        if (!FLAG_IS_DEFAULT(MaxVectorSize))
+          warning("MaxVectorSize must be <= 32");
+        FLAG_SET_DEFAULT(MaxVectorSize, 32);
+      }
+    }
+    else if (UseAVX > 2 ) {
+      if (MaxVectorSize > 64) {
+        if (!FLAG_IS_DEFAULT(MaxVectorSize))
+          warning("MaxVectorSize must be <= 64");
+        FLAG_SET_DEFAULT(MaxVectorSize, 64);
+      }
     }
 #if defined(COMPILER2) && defined(ASSERT)
     if (supports_avx() && PrintMiscellaneous && Verbose && TraceNewVectors) {
       tty->print_cr("State of YMM registers after signal handle:");
       int nreg = 2 LP64_ONLY(+2);