llvm: Export EliminateNewDuplicatePHINodes (llvm#169564)

This is needed for tests, when building with `LLVM_BUILD_LLVM_DYLIB` so
LLVM can be built as a DLL on Windows.

This effort is tracked in llvm#109483.

Author: Steelskin

llvm/include/llvm/Transforms/Utils/SSAUpdaterBulk.h

@@ -14,12 +14,12 @@
 #define LLVM_TRANSFORMS_UTILS_SSAUPDATERBULK_H
 
 #include "llvm/ADT/StringRef.h"
+#include "llvm/IR/BasicBlock.h"
 #include "llvm/IR/PredIteratorCache.h"
 #include "llvm/Support/Compiler.h"
 
 namespace llvm {
 
-class BasicBlock;
 class PHINode;
 template <typename T> class SmallVectorImpl;
 class Type;
@@ -84,6 +84,10 @@ class SSAUpdaterBulk {
   LLVM_ABI_FOR_TEST void RewriteAndOptimizeAllUses(DominatorTree &DT);
 };
 
+LLVM_ABI_FOR_TEST bool
+EliminateNewDuplicatePHINodes(BasicBlock *BB,
+                              BasicBlock::phi_iterator FirstExistingPN);
+
 } // end namespace llvm
 
 #endif // LLVM_TRANSFORMS_UTILS_SSAUPDATERBULK_H

llvm/lib/Transforms/Utils/SSAUpdaterBulk.cpp

@@ -267,6 +267,8 @@ static bool replaceIfIdentical(PHINode &PHI, PHINode &ReplPHI) {
   return true;
 }
 
+namespace llvm {
+
 bool EliminateNewDuplicatePHINodes(BasicBlock *BB,
                                    BasicBlock::phi_iterator FirstExistingPN) {
   assert(!PHIAreRefEachOther(make_range(BB->phis().begin(), FirstExistingPN)));
@@ -293,6 +295,8 @@ bool EliminateNewDuplicatePHINodes(BasicBlock *BB,
   return Changed;
 }
 
+} // end namespace llvm
+
 static void deduplicatePass(ArrayRef<PHINode *> Worklist) {
   SmallDenseMap<BasicBlock *, unsigned> BBs;
   for (PHINode *PHI : Worklist) {

llvm/unittests/Transforms/Utils/SSAUpdaterBulkTest.cpp

@@ -374,9 +374,6 @@ TEST(SSAUpdaterBulk, SimplifyPHIs) {
   EXPECT_EQ(Phi, Cmp->getOperand(1));
 }
 
-bool EliminateNewDuplicatePHINodes(BasicBlock *BB,
-                                   BasicBlock::phi_iterator FirstExistingPN);
-
 // Helper to run both versions on the same input.
 static void RunEliminateNewDuplicatePHINode(
     const char *AsmText,