[llvm] [VPlan] Separate out logic to manage IR flags to VPIRFlags (NFC). (PR #140621)

[via llvm-commits]

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@@ -164,25 +164,19 @@ class VPBuilder {
                               DebugLoc DL, const Twine &Name = "") {
     return createInstruction(Opcode, Operands, DL, Name);
   }
-  VPInstruction *createNaryOp(unsigned Opcode,
-                              std::initializer_list<VPValue *> Operands,
-                              std::optional<FastMathFlags> FMFs = {},
-                              DebugLoc DL = {}, const Twine &Name = "") {
-    if (FMFs)
-      return tryInsertInstruction(
-          new VPInstruction(Opcode, Operands, *FMFs, DL, Name));
-    return createInstruction(Opcode, Operands, DL, Name);
+  VPInstruction *createNaryOp(unsigned Opcode, ArrayRef<VPValue *> Operands,
+                              const VPIRFlags &Flags, DebugLoc DL = {},
+                              const Twine &Name = "") {
+    return tryInsertInstruction(
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ayalz wrote:

Consistency nit: worth overloading `createInstruction()` with a Flags-supporting version, to be used here and below?

https://github.com/llvm/llvm-project/pull/140621