[clang] [X86][Clang] Add AVX512 Integer Comparison Intrinsics for constexpr Evaluation (PR #164026)

[Simon Pilgrim via cfe-commits]

================
@@ -15449,6 +15449,91 @@ bool IntExprEvaluator::VisitBuiltinCallExpr(const CallExpr *E,
     unsigned Idx = static_cast<unsigned>(IdxAPS.getZExtValue() & (N - 1));
     return Success(Vec.getVectorElt(Idx).getInt(), E);
   }
+
+  case clang::X86::BI__builtin_ia32_cmpb128_mask:
+  case clang::X86::BI__builtin_ia32_cmpw128_mask:
+  case clang::X86::BI__builtin_ia32_cmpd128_mask:
+  case clang::X86::BI__builtin_ia32_cmpq128_mask:
+  case clang::X86::BI__builtin_ia32_cmpb256_mask:
+  case clang::X86::BI__builtin_ia32_cmpw256_mask:
+  case clang::X86::BI__builtin_ia32_cmpd256_mask:
+  case clang::X86::BI__builtin_ia32_cmpq256_mask:
+  case clang::X86::BI__builtin_ia32_cmpb512_mask:
+  case clang::X86::BI__builtin_ia32_cmpw512_mask:
+  case clang::X86::BI__builtin_ia32_cmpd512_mask:
+  case clang::X86::BI__builtin_ia32_cmpq512_mask:
+  case clang::X86::BI__builtin_ia32_ucmpb128_mask:
+  case clang::X86::BI__builtin_ia32_ucmpw128_mask:
+  case clang::X86::BI__builtin_ia32_ucmpd128_mask:
+  case clang::X86::BI__builtin_ia32_ucmpq128_mask:
+  case clang::X86::BI__builtin_ia32_ucmpb256_mask:
+  case clang::X86::BI__builtin_ia32_ucmpw256_mask:
+  case clang::X86::BI__builtin_ia32_ucmpd256_mask:
+  case clang::X86::BI__builtin_ia32_ucmpq256_mask:
+  case clang::X86::BI__builtin_ia32_ucmpb512_mask:
+  case clang::X86::BI__builtin_ia32_ucmpw512_mask:
+  case clang::X86::BI__builtin_ia32_ucmpd512_mask:
+  case clang::X86::BI__builtin_ia32_ucmpq512_mask: {
+    assert(E->getNumArgs() == 4);
+
+    bool IsUnsigned =
+        (BuiltinOp >= clang::X86::BI__builtin_ia32_ucmpb128_mask &&
+         BuiltinOp <= clang::X86::BI__builtin_ia32_ucmpq512_mask);
+
+    APValue LHS, RHS;
+    APSInt Mask, Opcode;
+    if (!EvaluateVector(E->getArg(0), LHS, Info) ||
+        !EvaluateVector(E->getArg(1), RHS, Info) ||
+        !EvaluateInteger(E->getArg(2), Opcode, Info) ||
+        !EvaluateInteger(E->getArg(3), Mask, Info))
+      return false;
+
+    assert(LHS.getVectorLength() == RHS.getVectorLength());
+
+    unsigned VectorLen = LHS.getVectorLength();
+    unsigned RetWidth = VectorLen ? VectorLen : 1;
+    if (Mask.getBitWidth() > RetWidth)
+      RetWidth = Mask.getBitWidth();
+
+    APSInt RetMask(llvm::APInt(RetWidth, 0), /*isUnsigned=*/true);
+    for (unsigned ElemNum = 0; ElemNum < VectorLen; ++ElemNum) {
+      APSInt A = LHS.getVectorElt(ElemNum).getInt();
+      APSInt B = RHS.getVectorElt(ElemNum).getInt();
----------------
RKSimon wrote:

```
      const APSInt &A = LHS.getVectorElt(ElemNum).getInt();
      const APSInt &B = RHS.getVectorElt(ElemNum).getInt();
```

https://github.com/llvm/llvm-project/pull/164026