Rewrite code for AVX handling to deal with broken cpuid states.

1 files changed, 59 insertions, 53 deletions

diff --git a/config.guess b/config.guess
index 1f37b3f50..fc4c54188 100755
--- a/config.guess
+++ b/config.guess
@@ -766,25 +766,23 @@ int
 main ()
 {
   char vendor_string[13];
-  char dummy_string[12];
+  char feature_string[12];
   long fms;
-  int family, model, stepping;
+  int family, model;
   const char *modelstr, *suffix;
-  int cpu_64bit = 0;
+  int cpu_64bit = 0, cpu_avx = 0;
   int cpuid_64bit, cpuid_avx, cpuid_osxsave;
 
   CPUID (vendor_string, 0);
   vendor_string[12] = 0;
 
-  fms = CPUID (dummy_string, 1);
+  fms = CPUID (feature_string, 1);
 
   family = ((fms >> 8) & 0xf) + ((fms >> 20) & 0xff);
   model = ((fms >> 4) & 0xf) + ((fms >> 12) & 0xf0);
-  stepping = fms & 0xf;
 
-  cpuid_avx     = (dummy_string[11] >> 4) & 1;
-  cpuid_osxsave = (dummy_string[11] >> 3) & 1;
-  suffix = cpuid_avx > cpuid_osxsave ? "noavx" : "";
+  cpuid_avx     = (feature_string[11] >> 4) & 1;
+  cpuid_osxsave = (feature_string[11] >> 3) & 1;
 
   modelstr = "$guess_cpu";
 
@@ -800,48 +798,48 @@ main ()
 	  else if (model >= 4)	modelstr = "pentiummmx";
 	  break;
 	case 6:
-          if (model <= 1)                        modelstr = "pentiumpro";
-          else if (model <= 6)                   modelstr = "pentium2";
-          else if (model <= 8)                   modelstr = "pentium3";
-          else if (model <= 9)                   modelstr = "pentiumm";
-          else if (model <= 0x0c)                modelstr = "pentium3";
-          else if (model <= 0x0e)                modelstr = "pentiumm";
-          else if (model <= 0x19) cpu_64bit = 1, modelstr = "core2";
-          else if (model == 0x1a) cpu_64bit = 1, modelstr = "nehalem";    /* NHM Gainestown */
-          else if (model == 0x1c) cpu_64bit = 1, modelstr = "atom";       /* Silverthorne */
-          else if (model == 0x1d) cpu_64bit = 1, modelstr = "core2";      /* PNR Dunnington */
-          else if (model == 0x1e) cpu_64bit = 1, modelstr = "nehalem";    /* NHM Lynnfield/Jasper */
-          else if (model == 0x25) cpu_64bit = 1, modelstr = "westmere";   /* WSM Clarkdale/Arrandale */
-          else if (model == 0x26) cpu_64bit = 1, modelstr = "atom";       /* Lincroft */
-          else if (model == 0x27) cpu_64bit = 1, modelstr = "atom";       /* Saltwell */
-          else if (model == 0x2a) cpu_64bit = 1, modelstr = "sandybridge";/* SB */
-          else if (model == 0x2c) cpu_64bit = 1, modelstr = "westmere";   /* WSM Gulftown */
-          else if (model == 0x2d) cpu_64bit = 1, modelstr = "sandybridge";/* SBC-EP */
-          else if (model == 0x2e) cpu_64bit = 1, modelstr = "nehalem";    /* NHM Beckton */
-          else if (model == 0x2f) cpu_64bit = 1, modelstr = "westmere";   /* WSM Eagleton */
-          else if (model == 0x36) cpu_64bit = 1, modelstr = "atom";       /* Cedarview/Saltwell */
-          else if (model == 0x37) cpu_64bit = 1, modelstr = "silvermont"; /* Atom Silvermont */
-          else if (model == 0x3a) cpu_64bit = 1, modelstr = "ivybridge";  /* IBR */
-          else if (model == 0x3c) cpu_64bit = 1, modelstr = "haswell";    /* Haswell client */
-          else if (model == 0x3d) cpu_64bit = 1, modelstr = "broadwell";  /* Broadwell */
-          else if (model == 0x3e) cpu_64bit = 1, modelstr = "ivybridge";  /* Ivytown */
-          else if (model == 0x3f) cpu_64bit = 1, modelstr = "haswell";    /* Haswell server */
-          else if (model == 0x45) cpu_64bit = 1, modelstr = "haswell";    /* Haswell ULT */
-          else if (model == 0x46) cpu_64bit = 1, modelstr = "haswell";    /* Crystal Well */
-          else if (model == 0x47) cpu_64bit = 1, modelstr = "broadwell";  /* Broadwell */
-          else if (model == 0x4a) cpu_64bit = 1, modelstr = "silvermont"; /* Silvermont */
-          else if (model == 0x4c) cpu_64bit = 1, modelstr = "silvermont"; /* Airmont */
-          else if (model == 0x4d) cpu_64bit = 1, modelstr = "silvermont"; /* Silvermont/Avoton */
-          else if (model == 0x4f) cpu_64bit = 1, modelstr = "broadwell";  /* Broadwell server */
-          else if (model == 0x56) cpu_64bit = 1, modelstr = "broadwell";  /* Broadwell microserver */
-          else cpu_64bit = 1, modelstr = "nehalem"; /* default */
+          if (model <= 1)                                   modelstr = "pentiumpro";
+          else if (model <= 6)                              modelstr = "pentium2";
+          else if (model <= 8)                              modelstr = "pentium3";
+          else if (model <= 9)                              modelstr = "pentiumm";
+          else if (model <= 0x0c)                           modelstr = "pentium3";
+          else if (model <= 0x0e)                           modelstr = "pentiumm";
+          else if (model <= 0x19) cpu_64bit = 1,            modelstr = "core2";
+          else if (model == 0x1a) cpu_64bit = 1,            modelstr = "nehalem";    /* NHM Gainestown */
+          else if (model == 0x1c) cpu_64bit = 1,            modelstr = "atom";       /* Silverthorne */
+          else if (model == 0x1d) cpu_64bit = 1,            modelstr = "core2";      /* PNR Dunnington */
+          else if (model == 0x1e) cpu_64bit = 1,            modelstr = "nehalem";    /* NHM Lynnfield/Jasper */
+          else if (model == 0x25) cpu_64bit = 1,            modelstr = "westmere";   /* WSM Clarkdale/Arrandale */
+          else if (model == 0x26) cpu_64bit = 1,            modelstr = "atom";       /* Lincroft */
+          else if (model == 0x27) cpu_64bit = 1,            modelstr = "atom";       /* Saltwell */
+          else if (model == 0x2a) cpu_64bit = 1, cpu_avx=1, modelstr = "sandybridge";/* SB */
+          else if (model == 0x2c) cpu_64bit = 1,            modelstr = "westmere";   /* WSM Gulftown */
+          else if (model == 0x2d) cpu_64bit = 1, cpu_avx=1, modelstr = "sandybridge";/* SBC-EP */
+          else if (model == 0x2e) cpu_64bit = 1,            modelstr = "nehalem";    /* NHM Beckton */
+          else if (model == 0x2f) cpu_64bit = 1,            modelstr = "westmere";   /* WSM Eagleton */
+          else if (model == 0x36) cpu_64bit = 1,            modelstr = "atom";       /* Cedarview/Saltwell */
+          else if (model == 0x37) cpu_64bit = 1,            modelstr = "silvermont"; /* Atom Silvermont */
+          else if (model == 0x3a) cpu_64bit = 1, cpu_avx=1, modelstr = "ivybridge";  /* IBR */
+          else if (model == 0x3c) cpu_64bit = 1, cpu_avx=1, modelstr = "haswell";    /* Haswell client */
+          else if (model == 0x3d) cpu_64bit = 1, cpu_avx=1, modelstr = "broadwell";  /* Broadwell */
+          else if (model == 0x3e) cpu_64bit = 1, cpu_avx=1, modelstr = "ivybridge";  /* Ivytown */
+          else if (model == 0x3f) cpu_64bit = 1, cpu_avx=1, modelstr = "haswell";    /* Haswell server */
+          else if (model == 0x45) cpu_64bit = 1, cpu_avx=1, modelstr = "haswell";    /* Haswell ULT */
+          else if (model == 0x46) cpu_64bit = 1, cpu_avx=1, modelstr = "haswell";    /* Crystal Well */
+          else if (model == 0x47) cpu_64bit = 1, cpu_avx=1, modelstr = "broadwell";  /* Broadwell */
+          else if (model == 0x4a) cpu_64bit = 1,            modelstr = "silvermont"; /* Silvermont */
+          else if (model == 0x4c) cpu_64bit = 1,            modelstr = "silvermont"; /* Airmont */
+          else if (model == 0x4d) cpu_64bit = 1,            modelstr = "silvermont"; /* Silvermont/Avoton */
+          else if (model == 0x4f) cpu_64bit = 1, cpu_avx=1, modelstr = "broadwell";  /* Broadwell server */
+          else if (model == 0x56) cpu_64bit = 1, cpu_avx=1, modelstr = "broadwell";  /* Broadwell microserver */
+          else                    cpu_64bit = 1,            modelstr = "nehalem";    /* default */
 
 	  if (strcmp (modelstr, "haswell") == 0)
 	    {
 	      /* Some Haswells lack BMI2.  Let them appear as Sandybridges for
 		 now.  */
-	      CPUID (dummy_string, 7);
-	      if ((dummy_string[0 + 8 / 8] & (1 << (8 % 8))) == 0)
+	      CPUID (feature_string, 7);
+	      if ((feature_string[0 + 8 / 8] & (1 << (8 % 8))) == 0)
 		modelstr = "sandybridge";
 	    }
 
@@ -885,7 +883,7 @@ main ()
 	  cpu_64bit = 1, modelstr = "bobcat";
 	  break;
 	case 21:		/* Bulldozer */
-	  cpu_64bit = 1;
+	  cpu_64bit = 1, cpu_avx = 1;
 	  if (model <= 1)
 	    modelstr = "bulldozer";
 	  else if (model < 0x20)	/* really 2, [0x10-0x20) */
@@ -896,7 +894,7 @@ main ()
 	    modelstr = "excavator";
 	  break;
 	case 22:		/* Jaguar, an improved bobcat */
-	  cpu_64bit = 1, modelstr = "jaguar";
+	  cpu_64bit = 1, cpu_avx = 1, modelstr = "jaguar";
 	  break;
 	}
     }
@@ -916,15 +914,23 @@ main ()
 	}
     }
 
-  CPUID (dummy_string, 0x80000001);
-  cpuid_64bit = (dummy_string[7] >> 5) & 1;
+  CPUID (feature_string, 0x80000001);
+  cpuid_64bit = (feature_string[7] >> 5) & 1;
+
+  suffix = "";
 
-  /* If our cpuid-based CPU identification thinks this is a 32-bit CPU but
-     cpuid claims AMD64 capabilities, then revert to the generic "x86_64".
-     This is of course wrong, but it can happen in some emulators, so this
-     workaround allows for successful 64-bit builds.  */
   if (cpuid_64bit && ! cpu_64bit)
+    /* If our cpuid-based CPU identification thinks this is a 32-bit CPU but
+       cpuid claims AMD64 capabilities, then revert to the generic "x86_64".
+       This is of course wrong, but it can happen in some virtualisers and
+       emulators, so this workaround allows for successful 64-bit builds.  */
     modelstr = "x86_64";
+  else if (cpu_avx && ! (cpuid_avx && cpuid_osxsave))
+    /* For CPUs nominally capable of executing AVX, append "noavx" when not
+       both the AVX and OSXSAVE cpuid bits are set.  We tolerate weirdness
+       here, as some virtualisers set a broken cpuid state here, while other
+       virtualisers allow users to set a broken state.  */
+    suffix = "noavx";
 
   printf ("%s%s", modelstr, suffix);
   return 0;