[Local] Add a convenient insertReplacementDbgValues overload, NFC

Add an overload for the common case where the replacement dbg.values
have the same DIExpressions as the originals.

llvm-svn: 335643

Author: vedantk

llvm/include/llvm/Transforms/Utils/Local.h

@@ -346,6 +346,11 @@ void insertReplacementDbgValues(
     Value &From, Value &To, Instruction &InsertBefore,
     function_ref<DIExpression *(DbgInfoIntrinsic &OldDII)> RewriteExpr);
 
+/// An overload of insertReplacementDbgValues() for the common case where
+/// the replacement dbg.values have the same DIExpressions as the originals.
+void insertReplacementDbgValues(Value &From, Value &To,
+                                Instruction &InsertBefore);
+
 /// Remove all instructions from a basic block other than it's terminator
 /// and any present EH pad instructions.
 unsigned removeAllNonTerminatorAndEHPadInstructions(BasicBlock *BB);

llvm/lib/Transforms/InstCombine/InstCombineCasts.cpp

@@ -267,13 +267,9 @@ Instruction *InstCombiner::commonCastTransforms(CastInst &CI) {
       // The first cast (CSrc) is eliminable so we need to fix up or replace
       // the second cast (CI). CSrc will then have a good chance of being dead.
       auto *Res = CastInst::Create(NewOpc, CSrc->getOperand(0), CI.getType());
-
       // Replace debug users of the eliminable cast by emitting debug values
       // which refer to the new cast.
-      insertReplacementDbgValues(
-          *CSrc, *Res, *std::next(CI.getIterator()),
-          [](DbgInfoIntrinsic &OldDII) { return OldDII.getExpression(); });
-
+      insertReplacementDbgValues(*CSrc, *Res, *std::next(CI.getIterator()));
       return Res;
     }
   }

llvm/lib/Transforms/Utils/Local.cpp

@@ -1717,9 +1717,19 @@ void llvm::insertReplacementDbgValues(
   // that the old debug users will be erased later.
   DIBuilder DIB(*InsertBefore.getModule());
   for (auto *OldDII : Users)
-    if (DIExpression *Expr = RewriteExpr(*OldDII))
-      DIB.insertDbgValueIntrinsic(&To, OldDII->getVariable(), Expr,
-                                  OldDII->getDebugLoc().get(), &InsertBefore);
+    if (DIExpression *Expr = RewriteExpr(*OldDII)) {
+      auto *I = DIB.insertDbgValueIntrinsic(&To, OldDII->getVariable(), Expr,
+                                            OldDII->getDebugLoc().get(),
+                                            &InsertBefore);
+      LLVM_DEBUG(dbgs() << "REPLACE:  " << *I << '\n');
+    }
+}
+
+void llvm::insertReplacementDbgValues(Value &From, Value &To,
+                                      Instruction &InsertBefore) {
+  return llvm::insertReplacementDbgValues(
+      From, To, InsertBefore,
+      [](DbgInfoIntrinsic &OldDII) { return OldDII.getExpression(); });
 }
 
 unsigned llvm::removeAllNonTerminatorAndEHPadInstructions(BasicBlock *BB) {