Minor comment update.
llvm-svn: 145905
diff --git a/clang/lib/CodeGen/TargetInfo.cpp b/clang/lib/CodeGen/TargetInfo.cpp
index 16d22dd..99cd579 100644
--- a/clang/lib/CodeGen/TargetInfo.cpp
+++ b/clang/lib/CodeGen/TargetInfo.cpp
@@ -988,7 +988,9 @@
// The default CC on x86-64 sets %al to the number of SSA
// registers used, and GCC sets this when calling an unprototyped
// function, so we override the default behavior. However, don't do
- // that when AVX types are involved.
+ // that when AVX types are involved: the ABI explicitly states it is
+ // undefined, and it doesn't work in practice because of how the ABI
+ // defines varargs anyway.
if (FI.getCallingConvention() == llvm::CallingConv::C) {
bool HasAVXType = false;
for (CGFunctionInfo::const_arg_iterator it = FI.arg_begin(),