Rename and move utility function getLatchPredicateForGuard. NFC.

Rename getLatchPredicateForGuard to more common name
getFlippedStrictnessPredicate and move it to ICmpInst class.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@324717 91177308-0d34-0410-b5e6-96231b3b80d8

Author: Serguei Katkov

include/llvm/IR/InstrTypes.h

@@ -973,6 +973,21 @@ class CmpInst : public Instruction {
   /// @brief Return the predicate as if the operands were swapped.
   static Predicate getSwappedPredicate(Predicate pred);
 
+  /// For predicate of kind "is X or equal to 0" returns the predicate "is X".
+  /// For predicate of kind "is X" returns the predicate "is X or equal to 0".
+  /// does not support other kind of predicates.
+  /// @returns the predicate that does not contains is equal to zero if
+  /// it had and vice versa.
+  /// @brief Return the flipped strictness of predicate
+  Predicate getFlippedStrictnessPredicate() const {
+    return getFlippedStrictnessPredicate(getPredicate());
+  }
+
+  /// This is a static version that you can use without an instruction
+  /// available.
+  /// @brief Return the flipped strictness of predicate
+  static Predicate getFlippedStrictnessPredicate(Predicate pred);
+
   /// For example, SGT -> SGE, SLT -> SLE, ULT -> ULE, UGT -> UGE.
   /// @brief Returns the non-strict version of strict comparisons.
   Predicate getNonStrictPredicate() const {

lib/IR/Instructions.cpp

@@ -3437,6 +3437,29 @@ ICmpInst::Predicate ICmpInst::getUnsignedPredicate(Predicate pred) {
   }
 }
 
+CmpInst::Predicate CmpInst::getFlippedStrictnessPredicate(Predicate pred) {
+  switch (pred) {
+    default: llvm_unreachable("Unknown or unsupported cmp predicate!");
+    case ICMP_SGT: return ICMP_SGE;
+    case ICMP_SLT: return ICMP_SLE;
+    case ICMP_SGE: return ICMP_SGT;
+    case ICMP_SLE: return ICMP_SLT;
+    case ICMP_UGT: return ICMP_UGE;
+    case ICMP_ULT: return ICMP_ULE;
+    case ICMP_UGE: return ICMP_UGT;
+    case ICMP_ULE: return ICMP_ULT;
+
+    case FCMP_OGT: return FCMP_OGE;
+    case FCMP_OLT: return FCMP_OLE;
+    case FCMP_OGE: return FCMP_OGT;
+    case FCMP_OLE: return FCMP_OLT;
+    case FCMP_UGT: return FCMP_UGE;
+    case FCMP_ULT: return FCMP_ULE;
+    case FCMP_UGE: return FCMP_UGT;
+    case FCMP_ULE: return FCMP_ULT;
+  }
+}
+
 CmpInst::Predicate CmpInst::getSwappedPredicate(Predicate pred) {
   switch (pred) {
     default: llvm_unreachable("Unknown cmp predicate!");

lib/Transforms/Scalar/LoopPredication.cpp

@@ -271,10 +271,6 @@ class LoopPredication {
   // so.
   Optional<LoopICmp> generateLoopLatchCheck(Type *RangeCheckType);
 
-  // Returns the latch predicate for guard. SGT -> SGE, UGT -> UGE, SGE -> SGT,
-  // UGE -> UGT, etc.
-  ICmpInst::Predicate getLatchPredicateForGuard(ICmpInst::Predicate Pred);
-
 public:
   LoopPredication(ScalarEvolution *SE) : SE(SE){};
   bool runOnLoop(Loop *L);
@@ -400,30 +396,6 @@ bool LoopPredication::CanExpand(const SCEV* S) {
   return SE->isLoopInvariant(S, L) && isSafeToExpand(S, *SE);
 }
 
-ICmpInst::Predicate
-LoopPredication::getLatchPredicateForGuard(ICmpInst::Predicate Pred) {
-  switch (LatchCheck.Pred) {
-  case ICmpInst::ICMP_ULT:
-    return ICmpInst::ICMP_ULE;
-  case ICmpInst::ICMP_ULE:
-    return ICmpInst::ICMP_ULT;
-  case ICmpInst::ICMP_SLT:
-    return ICmpInst::ICMP_SLE;
-  case ICmpInst::ICMP_SLE:
-    return ICmpInst::ICMP_SLT;
-  case ICmpInst::ICMP_UGT:
-    return ICmpInst::ICMP_UGE;
-  case ICmpInst::ICMP_UGE:
-    return ICmpInst::ICMP_UGT;
-  case ICmpInst::ICMP_SGT:
-    return ICmpInst::ICMP_SGE;
-  case ICmpInst::ICMP_SGE:
-    return ICmpInst::ICMP_SGT;
-  default:
-    llvm_unreachable("Unsupported loop latch!");
-  }
-}
-
 Optional<Value *> LoopPredication::widenICmpRangeCheckIncrementingLoop(
     LoopPredication::LoopICmp LatchCheck, LoopPredication::LoopICmp RangeCheck,
     SCEVExpander &Expander, IRBuilder<> &Builder) {
@@ -448,7 +420,8 @@ Optional<Value *> LoopPredication::widenICmpRangeCheckIncrementingLoop(
     DEBUG(dbgs() << "Can't expand limit check!\n");
     return None;
   }
-  auto LimitCheckPred = getLatchPredicateForGuard(LatchCheck.Pred);
+  auto LimitCheckPred =
+      ICmpInst::getFlippedStrictnessPredicate(LatchCheck.Pred);
 
   DEBUG(dbgs() << "LHS: " << *LatchLimit << "\n");
   DEBUG(dbgs() << "RHS: " << *RHS << "\n");
@@ -489,7 +462,8 @@ Optional<Value *> LoopPredication::widenICmpRangeCheckDecrementingLoop(
   // latchLimit <pred> 1.
   // See the header comment for reasoning of the checks.
   Instruction *InsertAt = Preheader->getTerminator();
-  auto LimitCheckPred = getLatchPredicateForGuard(LatchCheck.Pred);
+  auto LimitCheckPred =
+      ICmpInst::getFlippedStrictnessPredicate(LatchCheck.Pred);
   auto *FirstIterationCheck = expandCheck(Expander, Builder, ICmpInst::ICMP_ULT,
                                           GuardStart, GuardLimit, InsertAt);
   auto *LimitCheck = expandCheck(Expander, Builder, LimitCheckPred, LatchLimit,