[sil] Move partial apply combiner code from SILCombiner into InstOptUtils.h/SILCombinerApplyVisitor.cpp.

This is in preparation for moving this into the mandatory combiner.

Author: gottesmm

include/swift/SILOptimizer/Utils/InstOptUtils.h

@@ -161,12 +161,21 @@ bool tryCheckedCastBrJumpThreading(
 /// A structure containing callbacks that are called when an instruction is
 /// removed or added.
 struct InstModCallbacks {
-  using CallbackTy = std::function<void(SILInstruction *)>;
-  CallbackTy deleteInst = [](SILInstruction *inst) { inst->eraseFromParent(); };
-  CallbackTy createdNewInst = [](SILInstruction *) {};
-
-  InstModCallbacks(CallbackTy deleteInst, CallbackTy createdNewInst)
-      : deleteInst(deleteInst), createdNewInst(createdNewInst) {}
+  std::function<void(SILInstruction *)> deleteInst = [](SILInstruction *inst) {
+    inst->eraseFromParent();
+  };
+  std::function<void(SILInstruction *)> createdNewInst = [](SILInstruction *) {
+  };
+  std::function<void(SILValue, SILValue)> replaceValueUsesWith =
+      [](SILValue oldValue, SILValue newValue) {
+        oldValue->replaceAllUsesWith(newValue);
+      };
+
+  InstModCallbacks(decltype(deleteInst) deleteInst,
+                   decltype(createdNewInst) createdNewInst,
+                   decltype(replaceValueUsesWith) replaceValueUsesWith)
+      : deleteInst(deleteInst), createdNewInst(createdNewInst),
+        replaceValueUsesWith(replaceValueUsesWith) {}
   InstModCallbacks() = default;
   ~InstModCallbacks() = default;
   InstModCallbacks(const InstModCallbacks &) = default;
@@ -391,6 +400,10 @@ findLocalApplySites(FunctionRefBaseInst *fri);
 /// Gets the base implementation of a method.
 AbstractFunctionDecl *getBaseMethod(AbstractFunctionDecl *FD);
 
+SILInstruction *
+tryOptimizeApplyOfPartialApply(PartialApplyInst *pai, SILBuilder &builder,
+                               InstModCallbacks callbacks = InstModCallbacks());
+
 } // end namespace swift
 
 #endif

lib/SILOptimizer/Mandatory/MandatoryCombine.cpp

@@ -77,15 +77,17 @@ class MandatoryCombiner final
   SmallVector<SILInstruction *, 16> instructionsPendingDeletion;
 
 public:
-  MandatoryCombiner(
-      SmallVectorImpl<SILInstruction *> &createdInstructions)
+  MandatoryCombiner(SmallVectorImpl<SILInstruction *> &createdInstructions)
       : worklist("MC"), madeChange(false), iteration(0),
         instModCallbacks(
             [&](SILInstruction *instruction) {
               worklist.erase(instruction);
               instructionsPendingDeletion.push_back(instruction);
             },
-            [&](SILInstruction *instruction) { worklist.add(instruction); }),
+            [&](SILInstruction *instruction) { worklist.add(instruction); },
+            [this](SILValue oldValue, SILValue newValue) {
+              worklist.replaceValueUsesWith(oldValue, newValue);
+            }),
         createdInstructions(createdInstructions){};
 
   void addReachableCodeToWorklist(SILFunction &function);
@@ -216,6 +218,7 @@ bool MandatoryCombiner::doOneIteration(SILFunction &function,
 //===----------------------------------------------------------------------===//
 
 SILInstruction *MandatoryCombiner::visitApplyInst(ApplyInst *instruction) {
+
   // Apply this pass only to partial applies all of whose arguments are
   // trivial.
   auto calledValue = instruction->getCallee();

lib/SILOptimizer/SILCombiner/SILCombiner.h

@@ -236,8 +236,6 @@ class SILCombiner :
   // the result bit.
   SILInstruction *optimizeBuiltinCompareEq(BuiltinInst *AI, bool NegateResult);
 
-  SILInstruction *tryOptimizeApplyOfPartialApply(PartialApplyInst *PAI);
-
   SILInstruction *optimizeApplyOfConvertFunctionInst(FullApplySite AI,
                                                      ConvertFunctionInst *CFI);
 
@@ -253,6 +251,15 @@ class SILCombiner :
                                        StringRef FInverseName, StringRef FName);
 
 private:
+  InstModCallbacks getInstModCallbacks() {
+    return InstModCallbacks(
+        [this](SILInstruction *DeadInst) { eraseInstFromFunction(*DeadInst); },
+        [this](SILInstruction *NewInst) { Worklist.add(NewInst); },
+        [this](SILValue oldValue, SILValue newValue) {
+          replaceValueUsesWith(oldValue, newValue);
+        });
+  }
+
   FullApplySite rewriteApplyCallee(FullApplySite apply, SILValue callee);
 
   // Build concrete existential information using findInitExistential.