[llvm] X86: don't fallback to X86-32 calling convention in 64bit mode. (PR #225820)

[Phoebe Wang via llvm-commits]

================
@@ -513,7 +513,7 @@ def RetCC_X86 : CallingConv<[
   CCIfCC<"CallingConv::Intel_OCL_BI", CCDelegateTo<RetCC_Intel_OCL_BI>>,
 
   CCIfSubtarget<"is64Bit()", CCDelegateTo<RetCC_X86_64>>,
-  CCDelegateTo<RetCC_X86_32>
+  CCIfNotSubtarget<"is64Bit()", CCDelegateTo<RetCC_X86_32>>
----------------
phoebewang wrote:

This looks confusing, can we switch it to
```
CCIfNotSubtarget<"is64Bit()", CCDelegateTo<RetCC_X86_32>>,
CCDelegateTo<RetCC_X86_64>
```

https://github.com/llvm/llvm-project/pull/225820