Add an extension point for peephole optimizers.

This extension point allows adding passes that perform peephole optimizations
similar to the instruction combiner. These passes will be inserted after
each instance of the instruction combiner pass.

Differential Revision: http://reviews.llvm.org/D3905

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@209595 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm/Transforms/IPO/PassManagerBuilder.h

@@ -86,7 +86,12 @@ public:
     /// EP_EnabledOnOptLevel0 - This extension point allows adding passes that
     /// should not be disabled by O0 optimization level. The passes will be
     /// inserted after the inlining pass.
-    EP_EnabledOnOptLevel0
+    EP_EnabledOnOptLevel0,
+
+    /// EP_Peephole - This extension point allows adding passes that perform
+    /// peephole optimizations similar to the instruction combiner. These passes
+    /// will be inserted after each instance of the instruction combiner pass.
+    EP_Peephole,
   };
 
   /// The Optimization Level - Specify the basic optimization level.

lib/Transforms/IPO/PassManagerBuilder.cpp

@@ -157,6 +157,7 @@ void PassManagerBuilder::populateModulePassManager(PassManagerBase &MPM) {
     MPM.add(createDeadArgEliminationPass());  // Dead argument elimination
 
     MPM.add(createInstructionCombiningPass());// Clean up after IPCP & DAE
+    addExtensionsToPM(EP_Peephole, MPM);
     MPM.add(createCFGSimplificationPass());   // Clean up after IPCP & DAE
   }
 
@@ -183,6 +184,7 @@ void PassManagerBuilder::populateModulePassManager(PassManagerBase &MPM) {
   MPM.add(createCorrelatedValuePropagationPass()); // Propagate conditionals
   MPM.add(createCFGSimplificationPass());     // Merge & remove BBs
   MPM.add(createInstructionCombiningPass());  // Combine silly seq's
+  addExtensionsToPM(EP_Peephole, MPM);
 
   if (!DisableTailCalls)
     MPM.add(createTailCallEliminationPass()); // Eliminate tail calls
@@ -208,6 +210,7 @@ void PassManagerBuilder::populateModulePassManager(PassManagerBase &MPM) {
   // Run instcombine after redundancy elimination to exploit opportunities
   // opened up by them.
   MPM.add(createInstructionCombiningPass());
+  addExtensionsToPM(EP_Peephole, MPM);
   MPM.add(createJumpThreadingPass());         // Thread jumps
   MPM.add(createCorrelatedValuePropagationPass());
   MPM.add(createDeadStoreEliminationPass());  // Delete dead stores
@@ -222,6 +225,7 @@ void PassManagerBuilder::populateModulePassManager(PassManagerBase &MPM) {
   if (BBVectorize) {
     MPM.add(createBBVectorizePass());
     MPM.add(createInstructionCombiningPass());
+    addExtensionsToPM(EP_Peephole, MPM);
     if (OptLevel > 1 && UseGVNAfterVectorization)
       MPM.add(createGVNPass());           // Remove redundancies
     else
@@ -235,6 +239,7 @@ void PassManagerBuilder::populateModulePassManager(PassManagerBase &MPM) {
   MPM.add(createAggressiveDCEPass());         // Delete dead instructions
   MPM.add(createCFGSimplificationPass()); // Merge & remove BBs
   MPM.add(createInstructionCombiningPass());  // Clean up after everything.
+  addExtensionsToPM(EP_Peephole, MPM);
 
   // FIXME: This is a HACK! The inliner pass above implicitly creates a CGSCC
   // pass manager that we are specifically trying to avoid. To prevent this
@@ -247,6 +252,7 @@ void PassManagerBuilder::populateModulePassManager(PassManagerBase &MPM) {
   // as function calls, so that we can only pass them when the vectorizer
   // changed the code.
   MPM.add(createInstructionCombiningPass());
+  addExtensionsToPM(EP_Peephole, MPM);
   MPM.add(createCFGSimplificationPass());
 
   if (!DisableUnrollLoops)
@@ -299,6 +305,7 @@ void PassManagerBuilder::populateLTOPassManager(PassManagerBase &PM,
   // function pointers.  When this happens, we often have to resolve varargs
   // calls, etc, so let instcombine do this.
   PM.add(createInstructionCombiningPass());
+  addExtensionsToPM(EP_Peephole, PM);
 
   // Inline small functions
   if (RunInliner)
@@ -317,6 +324,7 @@ void PassManagerBuilder::populateLTOPassManager(PassManagerBase &PM,
 
   // The IPO passes may leave cruft around.  Clean up after them.
   PM.add(createInstructionCombiningPass());
+  addExtensionsToPM(EP_Peephole, PM);
   PM.add(createJumpThreadingPass());
 
   // Break up allocas
@@ -346,6 +354,7 @@ void PassManagerBuilder::populateLTOPassManager(PassManagerBase &PM,
 
   // Cleanup and simplify the code after the scalar optimizations.
   PM.add(createInstructionCombiningPass());
+  addExtensionsToPM(EP_Peephole, PM);
 
   PM.add(createJumpThreadingPass());