i386: Enable AVX/AVX512 features only if supported by OSXSAVE

Enable AVX and AVX512 features only if their states are supported by
OSXSAVE.

	PR target/85100
	* config/i386/cpuinfo.c (XCR_XFEATURE_ENABLED_MASK): New.
	(XSTATE_FP): Likewise.
	(XSTATE_SSE): Likewise.
	(XSTATE_YMM): Likewise.
	(XSTATE_OPMASK): Likewise.
	(XSTATE_ZMM): Likewise.
	(XSTATE_HI_ZMM): Likewise.
	(XCR_AVX_ENABLED_MASK): Likewise.
	(XCR_AVX512F_ENABLED_MASK): Likewise.
	(get_available_features): Enable AVX and AVX512 features only
	if their states are supported by OSXSAVE.

From-SVN: r258954

libgcc/ChangeLog

+2018-03-29  H.J. Lu  <hongjiu.lu@intel.com>
+
+	PR target/85100
+	* config/i386/cpuinfo.c (XCR_XFEATURE_ENABLED_MASK): New.
+	(XSTATE_FP): Likewise.
+	(XSTATE_SSE): Likewise.
+	(XSTATE_YMM): Likewise.
+	(XSTATE_OPMASK): Likewise.
+	(XSTATE_ZMM): Likewise.
+	(XSTATE_HI_ZMM): Likewise.
+	(XCR_AVX_ENABLED_MASK): Likewise.
+	(XCR_AVX512F_ENABLED_MASK): Likewise.
+	(get_available_features): Enable AVX and AVX512 features only
+	if their states are supported by OSXSAVE.
+
 2018-03-22  Igor Tsimbalist  <igor.v.tsimbalist@intel.com>
 
 	PR target/85025

libgcc/config/i386/cpuinfo.c

@@ -240,6 +240,40 @@ get_available_features (unsigned int ecx, unsigned int edx,
   unsigned int features = 0;
   unsigned int features2 = 0;
 
+  /* Get XCR_XFEATURE_ENABLED_MASK register with xgetbv.  */
+#define XCR_XFEATURE_ENABLED_MASK	0x0
+#define XSTATE_FP			0x1
+#define XSTATE_SSE			0x2
+#define XSTATE_YMM			0x4
+#define XSTATE_OPMASK			0x20
+#define XSTATE_ZMM			0x40
+#define XSTATE_HI_ZMM			0x80
+
+#define XCR_AVX_ENABLED_MASK \
+  (XSTATE_SSE | XSTATE_YMM)
+#define XCR_AVX512F_ENABLED_MASK \
+  (XSTATE_SSE | XSTATE_YMM | XSTATE_OPMASK | XSTATE_ZMM | XSTATE_HI_ZMM)
+
+  /* Check if AVX and AVX512 are usable.  */
+  int avx_usable = 0;
+  int avx512_usable = 0;
+  if ((ecx & bit_OSXSAVE))
+    {
+      /* Check if XMM, YMM, OPMASK, upper 256 bits of ZMM0-ZMM15 and
+         ZMM16-ZMM31 states are supported by OSXSAVE.  */
+      unsigned int xcrlow;
+      unsigned int xcrhigh;
+      asm (".byte 0x0f, 0x01, 0xd0"
+	   : "=a" (xcrlow), "=d" (xcrhigh)
+	   : "c" (XCR_XFEATURE_ENABLED_MASK));
+      if ((xcrlow & XCR_AVX_ENABLED_MASK) == XCR_AVX_ENABLED_MASK)
+	{
+	  avx_usable = 1;
+	  avx512_usable = ((xcrlow & XCR_AVX512F_ENABLED_MASK)
+			   == XCR_AVX512F_ENABLED_MASK);
+	}
+    }
+
 #define set_feature(f) \
   if (f < 32) features |= (1U << f); else features2 |= (1U << (f - 32))
 
@@ -265,10 +299,13 @@ get_available_features (unsigned int ecx, unsigned int edx,
     set_feature (FEATURE_SSE4_1);
   if (ecx & bit_SSE4_2)
     set_feature (FEATURE_SSE4_2);
-  if (ecx & bit_AVX)
-    set_feature (FEATURE_AVX);
-  if (ecx & bit_FMA)
-    set_feature (FEATURE_FMA);
+  if (avx_usable)
+    {
+      if (ecx & bit_AVX)
+	set_feature (FEATURE_AVX);
+      if (ecx & bit_FMA)
+	set_feature (FEATURE_FMA);
+    }
 
   /* Get Advanced Features at level 7 (eax = 7, ecx = 0). */
   if (max_cpuid_level >= 7)
@@ -276,44 +313,50 @@ get_available_features (unsigned int ecx, unsigned int edx,
       __cpuid_count (7, 0, eax, ebx, ecx, edx);
       if (ebx & bit_BMI)
 	set_feature (FEATURE_BMI);
-      if (ebx & bit_AVX2)
-	set_feature (FEATURE_AVX2);
+      if (avx_usable)
+	{
+	  if (ebx & bit_AVX2)
+	    set_feature (FEATURE_AVX2);
+	}
       if (ebx & bit_BMI2)
 	set_feature (FEATURE_BMI2);
-      if (ebx & bit_AVX512F)
-	set_feature (FEATURE_AVX512F);
-      if (ebx & bit_AVX512VL)
-	set_feature (FEATURE_AVX512VL);
-      if (ebx & bit_AVX512BW)
-	set_feature (FEATURE_AVX512BW);
-      if (ebx & bit_AVX512DQ)
-	set_feature (FEATURE_AVX512DQ);
-      if (ebx & bit_AVX512CD)
-	set_feature (FEATURE_AVX512CD);
-      if (ebx & bit_AVX512PF)
-	set_feature (FEATURE_AVX512PF);
-      if (ebx & bit_AVX512ER)
-	set_feature (FEATURE_AVX512ER);
-      if (ebx & bit_AVX512IFMA)
-	set_feature (FEATURE_AVX512IFMA);
-      if (ecx & bit_AVX512VBMI)
-	set_feature (FEATURE_AVX512VBMI);
-      if (ecx & bit_AVX512VBMI2)
-	set_feature (FEATURE_AVX512VBMI2);
-      if (ecx & bit_GFNI)
-	set_feature (FEATURE_GFNI);
-      if (ecx & bit_VPCLMULQDQ)
-	set_feature (FEATURE_VPCLMULQDQ);
-      if (ecx & bit_AVX512VNNI)
-	set_feature (FEATURE_AVX512VNNI);
-      if (ecx & bit_AVX512BITALG)
-	set_feature (FEATURE_AVX512BITALG);
-      if (ecx & bit_AVX512VPOPCNTDQ)
-	set_feature (FEATURE_AVX512VPOPCNTDQ);
-      if (edx & bit_AVX5124VNNIW)
-	set_feature (FEATURE_AVX5124VNNIW);
-      if (edx & bit_AVX5124FMAPS)
-	set_feature (FEATURE_AVX5124FMAPS);
+      if (avx512_usable)
+	{
+	  if (ebx & bit_AVX512F)
+	    set_feature (FEATURE_AVX512F);
+	  if (ebx & bit_AVX512VL)
+	    set_feature (FEATURE_AVX512VL);
+	  if (ebx & bit_AVX512BW)
+	    set_feature (FEATURE_AVX512BW);
+	  if (ebx & bit_AVX512DQ)
+	    set_feature (FEATURE_AVX512DQ);
+	  if (ebx & bit_AVX512CD)
+	    set_feature (FEATURE_AVX512CD);
+	  if (ebx & bit_AVX512PF)
+	    set_feature (FEATURE_AVX512PF);
+	  if (ebx & bit_AVX512ER)
+	    set_feature (FEATURE_AVX512ER);
+	  if (ebx & bit_AVX512IFMA)
+	    set_feature (FEATURE_AVX512IFMA);
+	  if (ecx & bit_AVX512VBMI)
+	    set_feature (FEATURE_AVX512VBMI);
+	  if (ecx & bit_AVX512VBMI2)
+	    set_feature (FEATURE_AVX512VBMI2);
+	  if (ecx & bit_GFNI)
+	    set_feature (FEATURE_GFNI);
+	  if (ecx & bit_VPCLMULQDQ)
+	    set_feature (FEATURE_VPCLMULQDQ);
+	  if (ecx & bit_AVX512VNNI)
+	    set_feature (FEATURE_AVX512VNNI);
+	  if (ecx & bit_AVX512BITALG)
+	    set_feature (FEATURE_AVX512BITALG);
+	  if (ecx & bit_AVX512VPOPCNTDQ)
+	    set_feature (FEATURE_AVX512VPOPCNTDQ);
+	  if (edx & bit_AVX5124VNNIW)
+	    set_feature (FEATURE_AVX5124VNNIW);
+	  if (edx & bit_AVX5124FMAPS)
+	    set_feature (FEATURE_AVX5124FMAPS);
+	}
     }
 
   /* Check cpuid level of extended features.  */
@@ -325,10 +368,13 @@ get_available_features (unsigned int ecx, unsigned int edx,
 
       if (ecx & bit_SSE4a)
 	set_feature (FEATURE_SSE4_A);
-      if (ecx & bit_FMA4)
-	set_feature (FEATURE_FMA4);
-      if (ecx & bit_XOP)
-	set_feature (FEATURE_XOP);
+      if (avx_usable)
+	{
+	  if (ecx & bit_FMA4)
+	    set_feature (FEATURE_FMA4);
+	  if (ecx & bit_XOP)
+	    set_feature (FEATURE_XOP);
+	}
     }
     
   __cpu_model.__cpu_features[0] = features;