SILSSAUpdater: use the InstructionDeleter utility for deleting branch instructions.

the SSA updater replaces branch instructions when adding phi arguments. For deleting the old instruction use the InstructionDeleter utility.

Author: eeckstein

include/swift/SILOptimizer/Utils/CFGOptUtils.h

@@ -47,21 +47,7 @@ struct InstModCallbacks;
 /// \return The created branch. The old branch is deleted.
 /// The argument is appended at the end of the argument tuple.
 TermInst *addNewEdgeValueToBranch(TermInst *branch, SILBasicBlock *dest,
-                                  SILValue val, InstModCallbacks &callbacks);
-
-/// Adds a new argument to an edge between a branch and a destination
-/// block.
-///
-/// \param branch The terminator to add the argument to.
-/// \param dest The destination block of the edge.
-/// \param val The value to the arguments of the branch.
-/// \return The created branch. The old branch is deleted.
-/// The argument is appended at the end of the argument tuple.
-inline TermInst *addNewEdgeValueToBranch(TermInst *branch, SILBasicBlock *dest,
-                                         SILValue val) {
-  InstModCallbacks callbacks;
-  return addNewEdgeValueToBranch(branch, dest, val, callbacks);
-}
+                                  SILValue val, InstructionDeleter &deleter);
 
 /// Changes the edge value between a branch and destination basic block
 /// at the specified index. Changes all edges from \p Branch to \p Dest to carry

include/swift/SILOptimizer/Utils/SILSSAUpdater.h

@@ -14,6 +14,7 @@
 #define SWIFT_SIL_SILSSAUPDATER_H
 
 #include "llvm/Support/Allocator.h"
+#include "swift/SILOptimizer/Utils/InstOptUtils.h"
 #include "swift/SIL/SILInstruction.h"
 #include "swift/SIL/SILValue.h"
 
@@ -58,6 +59,10 @@ class SILSSAUpdater {
   // If not null updated with inserted 'phi' nodes (SILArgument).
   SmallVectorImpl<SILPhiArgument *> *insertedPhis;
 
+  // Used to delete branch instructions when they are replaced for adding
+  // phi arguments.
+  InstructionDeleter deleter;
+
   // Not copyable.
   void operator=(const SILSSAUpdater &) = delete;
   SILSSAUpdater(const SILSSAUpdater &) = delete;
@@ -67,6 +72,8 @@ class SILSSAUpdater {
       SmallVectorImpl<SILPhiArgument *> *insertedPhis = nullptr);
   ~SILSSAUpdater();
 
+  InstructionDeleter &getDeleter() { return deleter; }
+
   void setInsertedPhis(SmallVectorImpl<SILPhiArgument *> *inputInsertedPhis) {
     insertedPhis = inputInsertedPhis;
   }

lib/SILOptimizer/Utils/CFGOptUtils.cpp

@@ -26,7 +26,7 @@ using namespace swift;
 
 TermInst *swift::addNewEdgeValueToBranch(TermInst *branch, SILBasicBlock *dest,
                                          SILValue val,
-                                         InstModCallbacks &callbacks) {
+                                         InstructionDeleter &deleter) {
   SILBuilderWithScope builder(branch);
   TermInst *newBr = nullptr;
 
@@ -53,7 +53,7 @@ TermInst *swift::addNewEdgeValueToBranch(TermInst *branch, SILBasicBlock *dest,
         cbi->getLoc(), cbi->getCondition(), cbi->getTrueBB(), trueArgs,
         cbi->getFalseBB(), falseArgs, cbi->getTrueBBCount(),
         cbi->getFalseBBCount());
-    callbacks.createdNewInst(newBr);
+    deleter.getCallbacks().createdNewInst(newBr);
   } else if (auto *bi = dyn_cast<BranchInst>(branch)) {
     SmallVector<SILValue, 8> args;
 
@@ -63,13 +63,13 @@ TermInst *swift::addNewEdgeValueToBranch(TermInst *branch, SILBasicBlock *dest,
     args.push_back(val);
     assert(args.size() == dest->getNumArguments());
     newBr = builder.createBranch(bi->getLoc(), bi->getDestBB(), args);
-    callbacks.createdNewInst(newBr);
+    deleter.getCallbacks().createdNewInst(newBr);
   } else {
     // At the moment we can only add arguments to br and cond_br.
     llvm_unreachable("Can't add argument to terminator");
   }
 
-  callbacks.deleteInst(branch);
+  deleter.forceDelete(branch);
 
   return newBr;
 }

lib/SILOptimizer/Utils/OwnershipOptUtils.cpp

@@ -78,7 +78,8 @@ insertOwnedBaseValueAlongBranchEdge(BranchInst *bi, SILValue innerCopy,
   // argument.
   auto *phiArg =
       destBB->createPhiArgument(innerCopy->getType(), OwnershipKind::Owned);
-  addNewEdgeValueToBranch(bi, destBB, innerCopy, callbacks);
+  InstructionDeleter deleter(callbacks);
+  addNewEdgeValueToBranch(bi, destBB, innerCopy, deleter);
 
   // Grab our predecessor blocks, ignoring us, add to the branch edge an
   // undef corresponding to our value.
@@ -93,7 +94,7 @@ insertOwnedBaseValueAlongBranchEdge(BranchInst *bi, SILValue innerCopy,
       continue;
     addNewEdgeValueToBranch(
         predBlock->getTerminator(), destBB,
-        SILUndef::get(innerCopy->getType(), *destBB->getParent()), callbacks);
+        SILUndef::get(innerCopy->getType(), *destBB->getParent()), deleter);
   }
 
   return phiArg;

lib/SILOptimizer/Utils/SILSSAUpdater.cpp

@@ -230,9 +230,10 @@ SILValue SILSSAUpdater::getValueInMiddleOfBlock(SILBasicBlock *block) {
 
   // Create a new phi node.
   SILPhiArgument *phiArg = block->createPhiArgument(type, OwnershipKind::Owned);
-  for (auto &pair : predVals)
-    addNewEdgeValueToBranch(pair.first->getTerminator(), block, pair.second);
-
+  for (auto &pair : predVals) {
+    addNewEdgeValueToBranch(pair.first->getTerminator(), block, pair.second,
+                            deleter);
+  }
   if (insertedPhis)
     insertedPhis->push_back(phiArg);
 
@@ -326,7 +327,8 @@ class SSAUpdaterTraits<SILSSAUpdater> {
 
     for (auto *predBlock : predBlockList) {
       TermInst *ti = predBlock->getTerminator();
-      addNewEdgeValueToBranch(ti, block, ssaUpdater->phiSentinel.get());
+      addNewEdgeValueToBranch(ti, block, ssaUpdater->phiSentinel.get(),
+                              ssaUpdater->deleter);
     }
 
     return phi;