Add constexpr.

Author: Mel-Chen

llvm/include/llvm/Transforms/Utils/LoopUtils.h

@@ -361,7 +361,7 @@ bool canSinkOrHoistInst(Instruction &I, AAResults *AA, DominatorTree *DT,
 
 /// Returns the llvm.vector.reduce intrinsic that corresponds to the recurrence
 /// kind.
-Intrinsic::ID getReductionIntrinsicID(RecurKind RK);
+constexpr Intrinsic::ID getReductionIntrinsicID(RecurKind RK);
 
 /// Returns the arithmetic instruction opcode used when expanding a reduction.
 unsigned getArithmeticReductionInstruction(Intrinsic::ID RdxID);

llvm/lib/IR/IntrinsicInst.cpp

@@ -599,14 +599,13 @@ Intrinsic::ID VPIntrinsic::getForOpcode(unsigned IROPC) {
   return Intrinsic::not_intrinsic;
 }
 
-Intrinsic::ID VPIntrinsic::getForIntrinsic(Intrinsic::ID Id) {
-  if (isVPIntrinsic(Id))
+constexpr static Intrinsic::ID getForIntrinsic(Intrinsic::ID Id) {
+  if (::isVPIntrinsic(Id))
     return Id;
 
   switch (Id) {
   default:
     break;
-
 #define BEGIN_REGISTER_VP_INTRINSIC(VPID, ...) break;
 #define VP_PROPERTY_FUNCTIONAL_INTRINSIC(INTRIN) case Intrinsic::INTRIN:
 #define END_REGISTER_VP_INTRINSIC(VPID) return Intrinsic::VPID;
@@ -615,6 +614,10 @@ Intrinsic::ID VPIntrinsic::getForIntrinsic(Intrinsic::ID Id) {
   return Intrinsic::not_intrinsic;
 }
 
+Intrinsic::ID VPIntrinsic::getForIntrinsic(Intrinsic::ID Id) {
+  return ::getForIntrinsic(Id);
+}
+
 bool VPIntrinsic::canIgnoreVectorLengthParam() const {
   using namespace PatternMatch;
 

llvm/lib/Transforms/Utils/LoopUtils.cpp

@@ -918,7 +918,7 @@ bool llvm::hasIterationCountInvariantInParent(Loop *InnerLoop,
   return true;
 }
 
-Intrinsic::ID llvm::getReductionIntrinsicID(RecurKind RK) {
+constexpr Intrinsic::ID llvm::getReductionIntrinsicID(RecurKind RK) {
   switch (RK) {
   default:
     llvm_unreachable("Unexpected recurrence kind");