Reword this comment to reference a more fundamental issue.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@93154 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/X86/X86FastISel.cpp b/lib/Target/X86/X86FastISel.cpp
index 10fba24..7e02d59 100644
--- a/lib/Target/X86/X86FastISel.cpp
+++ b/lib/Target/X86/X86FastISel.cpp
@@ -1230,8 +1230,8 @@
CC != CallingConv::X86_FastCall)
return false;
- // On X86, -tailcallopt changes the fastcc ABI. FastISel doesn't
- // handle this for now.
+ // fastcc with -tailcallopt is intended to provide a guaranteed
+ // tail call optimization. Fastisel doesn't know how to do that.
if (CC == CallingConv::Fast && PerformTailCallOpt)
return false;