[clang] [X86][ByteCode] Allow PSHUFB intrinsics to be used in constexpr #156612 (PR #163148)

[Shafik Yaghmour via cfe-commits]

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@@ -2790,6 +2790,34 @@ static bool interp__builtin_blend(InterpState &S, CodePtr OpPC,
   return true;
 }
 
+static bool interp__builtin_ia32_pshufb(InterpState &S, CodePtr OpPC,
+                                        const CallExpr *Call) {
+  assert(Call->getNumArgs() == 2 && "masked forms handled via select*");
+  const Pointer &Control = S.Stk.pop<Pointer>();
+  const Pointer &Src = S.Stk.pop<Pointer>();
+  const Pointer &Dst = S.Stk.peek<Pointer>();
+
+  unsigned NumElems = Dst.getNumElems();
+  assert(NumElems == Control.getNumElems());
+  assert(NumElems == Dst.getNumElems());
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shafik wrote:

You are asserting the assignment right before the asserts? Was that what you meant to do?

https://github.com/llvm/llvm-project/pull/163148