[llvm] r308163 - [X86] Use MSVC's __cpuidex intrinsic instead of inline assembly in getHostCPUName/getHostCPUFeatures for 32-bit builds too.

[Craig Topper via llvm-commits]

Author: ctopper
Date: Sun Jul 16 22:16:16 2017
New Revision: 308163

URL: http://llvm.org/viewvc/llvm-project?rev=308163&view=rev
Log:
[X86] Use MSVC's __cpuidex intrinsic instead of inline assembly in getHostCPUName/getHostCPUFeatures for 32-bit builds too.

We're already using it in 64-bit builds because 64-bit MSVC doesn't support inline assembly.

As far as I know we were using inline assembly because at the time the code was added we had to support MSVC 2008 pre-SP1 while the intrinsic was added to MSVC in SP1. Now that we don't have to support that we should be able to just use the intrinsic.

Modified:
    llvm/trunk/lib/Support/Host.cpp

Modified: llvm/trunk/lib/Support/Host.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Support/Host.cpp?rev=308163&r1=308162&r2=308163&view=diff
==============================================================================
--- llvm/trunk/lib/Support/Host.cpp (original)
+++ llvm/trunk/lib/Support/Host.cpp Sun Jul 16 22:16:16 2017
@@ -460,8 +460,8 @@ static bool getX86CpuIDAndInfo(unsigned
 static bool getX86CpuIDAndInfoEx(unsigned value, unsigned subleaf,
                                  unsigned *rEAX, unsigned *rEBX, unsigned *rECX,
                                  unsigned *rEDX) {
-#if defined(__x86_64__) || defined(_M_X64)
 #if defined(__GNUC__) || defined(__clang__)
+#if defined(__x86_64__)
   // gcc doesn't know cpuid would clobber ebx/rbx. Preserve it manually.
   // FIXME: should we save this for Clang?
   __asm__("movq\t%%rbx, %%rsi\n\t"
@@ -470,43 +470,24 @@ static bool getX86CpuIDAndInfoEx(unsigne
           : "=a"(*rEAX), "=S"(*rEBX), "=c"(*rECX), "=d"(*rEDX)
           : "a"(value), "c"(subleaf));
   return false;
-#elif defined(_MSC_VER)
-  int registers[4];
-  __cpuidex(registers, value, subleaf);
-  *rEAX = registers[0];
-  *rEBX = registers[1];
-  *rECX = registers[2];
-  *rEDX = registers[3];
-  return false;
-#else
-  return true;
-#endif
-#elif defined(__i386__) || defined(_M_IX86)
-#if defined(__GNUC__) || defined(__clang__)
+#elif defined(__i386__)
   __asm__("movl\t%%ebx, %%esi\n\t"
           "cpuid\n\t"
           "xchgl\t%%ebx, %%esi\n\t"
           : "=a"(*rEAX), "=S"(*rEBX), "=c"(*rECX), "=d"(*rEDX)
           : "a"(value), "c"(subleaf));
   return false;
-#elif defined(_MSC_VER)
-  __asm {
-      mov   eax,value
-      mov   ecx,subleaf
-      cpuid
-      mov   esi,rEAX
-      mov   dword ptr [esi],eax
-      mov   esi,rEBX
-      mov   dword ptr [esi],ebx
-      mov   esi,rECX
-      mov   dword ptr [esi],ecx
-      mov   esi,rEDX
-      mov   dword ptr [esi],edx
-  }
-  return false;
 #else
   return true;
 #endif
+#elif defined(_MSC_VER)
+  int registers[4];
+  __cpuidex(registers, value, subleaf);
+  *rEAX = registers[0];
+  *rEBX = registers[1];
+  *rECX = registers[2];
+  *rEDX = registers[3];
+  return false;
 #else
   return true;
 #endif