Add method for replacing instructions to LibCallSimplifier

In some cases the library call simplifier may need to replace instructions
other than the library call being simplified.  In those cases it may be
necessary for clients of the simplifier to override how the replacements
are actually done.  As such, a new overrideable method for replacing
instructions was added to LibCallSimplifier.

A new subclass of LibCallSimplifier is also defined which overrides
the instruction replacement method.  This is because the instruction
combiner defines its own replacement method which updates the worklist
when instructions are replaced.

llvm-svn: 167681

1 files changed, 15 insertions, 4 deletions

diff --git a/llvm/lib/Transforms/Utils/SimplifyLibCalls.cpp b/llvm/lib/Transforms/Utils/SimplifyLibCalls.cpp
index 74d4e22fa44..e3e9266e523 100644
--- a/llvm/lib/Transforms/Utils/SimplifyLibCalls.cpp
+++ b/llvm/lib/Transforms/Utils/SimplifyLibCalls.cpp
@@ -34,6 +34,7 @@ protected:
   Function *Caller;
   const DataLayout *TD;
   const TargetLibraryInfo *TLI;
+  const LibCallSimplifier *LCS;
   LLVMContext* Context;
 public:
   LibCallOptimization() { }
@@ -48,10 +49,12 @@ public:
     =0;
 
   Value *optimizeCall(CallInst *CI, const DataLayout *TD,
-                      const TargetLibraryInfo *TLI, IRBuilder<> &B) {
+                      const TargetLibraryInfo *TLI,
+                      const LibCallSimplifier *LCS, IRBuilder<> &B) {
     Caller = CI->getParent()->getParent();
     this->TD = TD;
     this->TLI = TLI;
+    this->LCS = LCS;
     if (CI->getCalledFunction())
       Context = &CI->getCalledFunction()->getContext();
 
@@ -840,6 +843,7 @@ namespace llvm {
 class LibCallSimplifierImpl {
   const DataLayout *TD;
   const TargetLibraryInfo *TLI;
+  const LibCallSimplifier *LCS;
   StringMap<LibCallOptimization*> Optimizations;
 
   // Fortified library call optimizations.
@@ -869,9 +873,11 @@ class LibCallSimplifierImpl {
   void initOptimizations();
   void addOpt(LibFunc::Func F, LibCallOptimization* Opt);
 public:
-  LibCallSimplifierImpl(const DataLayout *TD, const TargetLibraryInfo *TLI) {
+  LibCallSimplifierImpl(const DataLayout *TD, const TargetLibraryInfo *TLI,
+                        const LibCallSimplifier *LCS) {
     this->TD = TD;
     this->TLI = TLI;
+    this->LCS = LCS;
   }
 
   Value *optimizeCall(CallInst *CI);
@@ -918,7 +924,7 @@ Value *LibCallSimplifierImpl::optimizeCall(CallInst *CI) {
   LibCallOptimization *LCO = Optimizations.lookup(Callee->getName());
   if (LCO) {
     IRBuilder<> Builder(CI);
-    return LCO->optimizeCall(CI, TD, TLI, Builder);
+    return LCO->optimizeCall(CI, TD, TLI, LCS, Builder);
   }
   return 0;
 }
@@ -930,7 +936,7 @@ void LibCallSimplifierImpl::addOpt(LibFunc::Func F, LibCallOptimization* Opt) {
 
 LibCallSimplifier::LibCallSimplifier(const DataLayout *TD,
                                      const TargetLibraryInfo *TLI) {
-  Impl = new LibCallSimplifierImpl(TD, TLI);
+  Impl = new LibCallSimplifierImpl(TD, TLI, this);
 }
 
 LibCallSimplifier::~LibCallSimplifier() {
@@ -941,4 +947,9 @@ Value *LibCallSimplifier::optimizeCall(CallInst *CI) {
   return Impl->optimizeCall(CI);
 }
 
+void LibCallSimplifier::replaceAllUsesWith(Instruction *I, Value *With) const {
+  I->replaceAllUsesWith(With);
+  I->eraseFromParent();
+}
+
 }