[clang] Replace llvm.memcpy et al's i1 isVolatile with i8 VolFlags (PR #65748)

[Mehdi Amini via cfe-commits]

================
@@ -214,14 +214,14 @@ class LLVM_MemcpyIntrOpBase<string name> :
     /*requiresAccessGroup=*/1, /*requiresAliasAnalysis=*/1> {
   dag args = (ins Arg<LLVM_AnyPointer,"",[MemWrite]>:$dst,
                   Arg<LLVM_AnyPointer,"",[MemRead]>:$src,
-                  AnySignlessInteger:$len, I1Attr:$isVolatile);
----------------
joker-eph wrote:

Seems to me that should handle this as we do with the FastMathFlags: that is a enum attribute modeling the bitfields.

https://github.com/llvm/llvm-project/pull/65748