[llvm] r307520 - [X86] Remove asserts from getX86CpuIDAndInfo/getX86CpuIDAndInfoEx. Restore past behavior of returning an unsupported indication to the caller instead.

[Craig Topper via llvm-commits]

Author: ctopper
Date: Sun Jul  9 23:04:11 2017
New Revision: 307520

URL: http://llvm.org/viewvc/llvm-project?rev=307520&view=rev
Log:
[X86] Remove asserts from getX86CpuIDAndInfo/getX86CpuIDAndInfoEx. Restore past behavior of returning an unsupported indication to the caller instead.

These asserts could only occur if we fail to properly detect the compiler, but an assert is not a good way to do that because it doesn't work in release builds.

I wonder if we could use #error?

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=307520&r1=307519&r2=307520&view=diff
==============================================================================
--- llvm/trunk/lib/Support/Host.cpp (original)
+++ llvm/trunk/lib/Support/Host.cpp Sun Jul  9 23:04:11 2017
@@ -406,7 +406,6 @@ static bool isCpuIdSupported() {
 /// the specified arguments.  If we can't run cpuid on the host, return true.
 static bool getX86CpuIDAndInfo(unsigned value, unsigned *rEAX, unsigned *rEBX,
                                unsigned *rECX, unsigned *rEDX) {
-#if defined(__GNUC__) || defined(__clang__) || defined(_MSC_VER)
 #if defined(__GNUC__) || defined(__clang__)
 #if defined(__x86_64__)
   // gcc doesn't know cpuid would clobber ebx/rbx. Preserve it manually.
@@ -416,14 +415,16 @@ static bool getX86CpuIDAndInfo(unsigned
           "xchgq\t%%rbx, %%rsi\n\t"
           : "=a"(*rEAX), "=S"(*rEBX), "=c"(*rECX), "=d"(*rEDX)
           : "a"(value));
+  return false;
 #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));
+  return false;
 #else
-  assert(0 && "This method is defined only for x86.");
+  return true;
 #endif
 #elif defined(_MSC_VER)
   // The MSVC intrinsic is portable across x86 and x64.
@@ -433,7 +434,6 @@ static bool getX86CpuIDAndInfo(unsigned
   *rEBX = registers[1];
   *rECX = registers[2];
   *rEDX = registers[3];
-#endif
   return false;
 #else
   return true;
@@ -446,7 +446,6 @@ static bool getX86CpuIDAndInfo(unsigned
 static bool getX86CpuIDAndInfoEx(unsigned value, unsigned subleaf,
                                  unsigned *rEAX, unsigned *rEBX, unsigned *rECX,
                                  unsigned *rEDX) {
-#if defined(__GNUC__) || defined(__clang__) || defined(_MSC_VER)
 #if defined(__x86_64__) || defined(_M_X64)
 #if defined(__GNUC__) || defined(__clang__)
   // gcc doesn't know cpuid would clobber ebx/rbx. Preseve it manually.
@@ -456,6 +455,7 @@ static bool getX86CpuIDAndInfoEx(unsigne
           "xchgq\t%%rbx, %%rsi\n\t"
           : "=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);
@@ -463,6 +463,9 @@ static bool getX86CpuIDAndInfoEx(unsigne
   *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__)
@@ -471,6 +474,7 @@ static bool getX86CpuIDAndInfoEx(unsigne
           "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
@@ -485,11 +489,10 @@ static bool getX86CpuIDAndInfoEx(unsigne
       mov   esi,rEDX
       mov   dword ptr [esi],edx
   }
-#endif
+  return false;
 #else
-  assert(0 && "This method is defined only for x86.");
+  return true;
 #endif
-  return false;
 #else
   return true;
 #endif