Make computeKnownBitsFromICmpCond part of the public API.

Author: wermos

llvm/include/llvm/Analysis/ValueTracking.h

@@ -102,6 +102,15 @@ LLVM_ABI void computeKnownBitsFromContext(const Value *V, KnownBits &Known,
                                           const SimplifyQuery &Q,
                                           unsigned Depth = 0);
 
+/// Update \p Known with bits of \p V that are implied by \p Cmp.
+/// Comparisons involving `trunc V` are handled specially: known
+/// bits are computed for the truncated value and then extended to the bitwidth
+/// of \p V.
+LLVM_ABI void computeKnownBitsFromICmpCond(const Value *V, ICmpInst *Cmp,
+                                           KnownBits &Known,
+                                           const SimplifyQuery &SQ,
+                                           bool Invert);
+
 /// Using KnownBits LHS/RHS produce the known bits for logic op (and/xor/or).
 LLVM_ABI KnownBits analyzeKnownBitsFromAndXorOr(const Operator *I,
                                                 const KnownBits &KnownLHS,

llvm/lib/Analysis/ValueTracking.cpp

@@ -968,9 +968,9 @@ static void computeKnownBitsFromCmp(const Value *V, CmpInst::Predicate Pred,
   }
 }
 
-static void computeKnownBitsFromICmpCond(const Value *V, ICmpInst *Cmp,
-                                         KnownBits &Known,
-                                         const SimplifyQuery &SQ, bool Invert) {
+void llvm::computeKnownBitsFromICmpCond(const Value *V, ICmpInst *Cmp,
+                                        KnownBits &Known,
+                                        const SimplifyQuery &SQ, bool Invert) {
   ICmpInst::Predicate Pred =
       Invert ? Cmp->getInversePredicate() : Cmp->getPredicate();
   Value *LHS = Cmp->getOperand(0);