Revert "[VP] vp intrinsics are not speculatable"

This reverts commit 78a18d2.

Break MLIR bot: https://lab.llvm.org/buildbot/#/builders/61/builds/27127

llvm/include/llvm/Analysis/ValueTracking.h

@@ -463,28 +463,6 @@ constexpr unsigned MaxAnalysisRecursionDepth = 6;
                                     const DominatorTree *DT = nullptr,
                                     const TargetLibraryInfo *TLI = nullptr);
 
-  /// This returns the same result as isSafeToSpeculativelyExecute if Opcode is
-  /// the actual opcode of Inst. If the provided and actual opcode differ, the
-  /// function (virtually) overrides the opcode of Inst with the provided
-  /// Opcode. There are come constraints in this case:
-  /// * If Opcode has a fixed number of operands (eg, as binary operators do),
-  ///   then Inst has to have at least as many leading operands. The function
-  ///   will ignore all trailing operands beyond that number.
-  /// * If Opcode allows for an arbitrary number of operands (eg, as CallInsts
-  ///   do), then all operands are considered.
-  /// * The virtual instruction has to satisfy all typing rules of the provided
-  ///   Opcode.
-  /// * This function is pessimistic in the following sense: If one actually
-  ///   materialized the virtual instruction, then isSafeToSpeculativelyExecute
-  ///   may say that the materialized instruction is speculatable whereas this
-  ///   function may have said that the instruction wouldn't be speculatable.
-  ///   This behavior is a shortcoming in the current implementation and not
-  ///   intentional.
-  bool isSafeToSpeculativelyExecuteWithOpcode(
-      unsigned Opcode, const Operator *Inst, const Instruction *CtxI = nullptr,
-      const DominatorTree *DT = nullptr,
-      const TargetLibraryInfo *TLI = nullptr);
-
   /// Returns true if the result or effects of the given instructions \p I
   /// depend values not reachable through the def use graph.
   /// * Memory dependence arises for example if the instruction reads from