[PM] Port InstSimplify to the new pass manager.

llvm-svn: 274796

include/llvm/Transforms/Utils/SimplifyInstructions.h

@@ -0,0 +1,31 @@
+//===- SimplifyInstructions.h - Remove redundant instructions ---*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This is a utility pass used for testing the InstructionSimplify analysis.
+// The analysis is applied to every instruction, and if it simplifies then the
+// instruction is replaced by the simplification.  If you are looking for a pass
+// that performs serious instruction folding, use the instcombine pass instead.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_TRANSFORMS_UTILS_SIMPLIFYINSTRUCTIONS_H
+#define LLVM_TRANSFORMS_UTILS_SIMPLIFYINSTRUCTIONS_H
+
+#include "llvm/IR/PassManager.h"
+
+namespace llvm {
+
+/// This pass removes redundant instructions.
+class InstSimplifierPass : public PassInfoMixin<InstSimplifierPass> {
+public:
+  PreservedAnalyses run(Function &F, AnalysisManager<Function> &AM);
+};
+} // end namespace llvm
+
+#endif // LLVM_TRANSFORMS_UTILS_SIMPLIFYINSTRUCTIONS_H

lib/Passes/PassBuilder.cpp

@@ -103,6 +103,7 @@
 #include "llvm/Transforms/Utils/LCSSA.h"
 #include "llvm/Transforms/Utils/Mem2Reg.h"
 #include "llvm/Transforms/Utils/MemorySSA.h"
+#include "llvm/Transforms/Utils/SimplifyInstructions.h"
 
 #include <type_traits>
 

lib/Passes/PassRegistry.def

@@ -132,6 +132,7 @@ FUNCTION_PASS("dce", DCEPass())
 FUNCTION_PASS("dse", DSEPass())
 FUNCTION_PASS("early-cse", EarlyCSEPass())
 FUNCTION_PASS("instcombine", InstCombinePass())
+FUNCTION_PASS("instsimplify", InstSimplifierPass())
 FUNCTION_PASS("invalidate<all>", InvalidateAllAnalysesPass())
 FUNCTION_PASS("float2int", Float2IntPass())
 FUNCTION_PASS("no-op-function", NoOpFunctionPass())

lib/Transforms/Utils/SimplifyInstructions.cpp

@@ -14,7 +14,7 @@
 //
 //===----------------------------------------------------------------------===//
 
-#include "llvm/Transforms/Scalar.h"
+#include "llvm/Transforms/Utils/SimplifyInstructions.h"
 #include "llvm/ADT/DepthFirstIterator.h"
 #include "llvm/ADT/SmallPtrSet.h"
 #include "llvm/ADT/Statistic.h"
@@ -27,12 +27,60 @@
 #include "llvm/IR/Type.h"
 #include "llvm/Pass.h"
 #include "llvm/Transforms/Utils/Local.h"
+#include "llvm/Transforms/Scalar.h"
 using namespace llvm;
 
 #define DEBUG_TYPE "instsimplify"
 
 STATISTIC(NumSimplified, "Number of redundant instructions removed");
 
+static bool runImpl(Function &F, const DominatorTree *DT, const TargetLibraryInfo *TLI,
+                    AssumptionCache *AC) {
+  const DataLayout &DL = F.getParent()->getDataLayout();
+  SmallPtrSet<const Instruction*, 8> S1, S2, *ToSimplify = &S1, *Next = &S2;
+  bool Changed = false;
+
+  do {
+    for (BasicBlock *BB : depth_first(&F.getEntryBlock()))
+      // Here be subtlety: the iterator must be incremented before the loop
+      // body (not sure why), so a range-for loop won't work here.
+      for (BasicBlock::iterator BI = BB->begin(), BE = BB->end(); BI != BE;) {
+        Instruction *I = &*BI++;
+        // The first time through the loop ToSimplify is empty and we try to
+        // simplify all instructions.  On later iterations ToSimplify is not
+        // empty and we only bother simplifying instructions that are in it.
+        if (!ToSimplify->empty() && !ToSimplify->count(I))
+          continue;
+        // Don't waste time simplifying unused instructions.
+        if (!I->use_empty())
+          if (Value *V = SimplifyInstruction(I, DL, TLI, DT, AC)) {
+            // Mark all uses for resimplification next time round the loop.
+            for (User *U : I->users())
+              Next->insert(cast<Instruction>(U));
+            I->replaceAllUsesWith(V);
+            ++NumSimplified;
+            Changed = true;
+          }
+        bool res = RecursivelyDeleteTriviallyDeadInstructions(I, TLI);
+        if (res)  {
+          // RecursivelyDeleteTriviallyDeadInstruction can remove
+          // more than one instruction, so simply incrementing the
+          // iterator does not work. When instructions get deleted
+          // re-iterate instead.
+          BI = BB->begin(); BE = BB->end();
+          Changed |= res;
+        }
+      }
+
+    // Place the list of instructions to simplify on the next loop iteration
+    // into ToSimplify.
+    std::swap(ToSimplify, Next);
+    Next->clear();
+  } while (!ToSimplify->empty());
+
+  return Changed;
+}
+
 namespace {
   struct InstSimplifier : public FunctionPass {
     static char ID; // Pass identification, replacement for typeid
@@ -54,53 +102,11 @@ namespace {
       const DominatorTreeWrapperPass *DTWP =
           getAnalysisIfAvailable<DominatorTreeWrapperPass>();
       const DominatorTree *DT = DTWP ? &DTWP->getDomTree() : nullptr;
-      const DataLayout &DL = F.getParent()->getDataLayout();
       const TargetLibraryInfo *TLI =
           &getAnalysis<TargetLibraryInfoWrapperPass>().getTLI();
       AssumptionCache *AC =
           &getAnalysis<AssumptionCacheTracker>().getAssumptionCache(F);
-      SmallPtrSet<const Instruction*, 8> S1, S2, *ToSimplify = &S1, *Next = &S2;
-      bool Changed = false;
-
-      do {
-        for (BasicBlock *BB : depth_first(&F.getEntryBlock()))
-          // Here be subtlety: the iterator must be incremented before the loop
-          // body (not sure why), so a range-for loop won't work here.
-          for (BasicBlock::iterator BI = BB->begin(), BE = BB->end(); BI != BE;) {
-            Instruction *I = &*BI++;
-            // The first time through the loop ToSimplify is empty and we try to
-            // simplify all instructions.  On later iterations ToSimplify is not
-            // empty and we only bother simplifying instructions that are in it.
-            if (!ToSimplify->empty() && !ToSimplify->count(I))
-              continue;
-            // Don't waste time simplifying unused instructions.
-            if (!I->use_empty())
-              if (Value *V = SimplifyInstruction(I, DL, TLI, DT, AC)) {
-                // Mark all uses for resimplification next time round the loop.
-                for (User *U : I->users())
-                  Next->insert(cast<Instruction>(U));
-                I->replaceAllUsesWith(V);
-                ++NumSimplified;
-                Changed = true;
-              }
-            bool res = RecursivelyDeleteTriviallyDeadInstructions(I, TLI);
-            if (res)  {
-              // RecursivelyDeleteTriviallyDeadInstruction can remove
-              // more than one instruction, so simply incrementing the
-              // iterator does not work. When instructions get deleted
-              // re-iterate instead.
-              BI = BB->begin(); BE = BB->end();
-              Changed |= res;
-            }
-          }
-
-        // Place the list of instructions to simplify on the next loop iteration
-        // into ToSimplify.
-        std::swap(ToSimplify, Next);
-        Next->clear();
-      } while (!ToSimplify->empty());
-
-      return Changed;
+      return runImpl(F, DT, TLI, AC);
     }
   };
 }
@@ -118,3 +124,15 @@ char &llvm::InstructionSimplifierID = InstSimplifier::ID;
 FunctionPass *llvm::createInstructionSimplifierPass() {
   return new InstSimplifier();
 }
+
+PreservedAnalyses InstSimplifierPass::run(Function &F,
+                                      AnalysisManager<Function> &AM) {
+  auto *DT = AM.getCachedResult<DominatorTreeAnalysis>(F);
+  auto &TLI = AM.getResult<TargetLibraryAnalysis>(F);
+  auto &AC = AM.getResult<AssumptionAnalysis>(F);
+  bool Changed = runImpl(F, DT, &TLI, &AC);
+  if (!Changed)
+    return PreservedAnalyses::all();
+  // FIXME: This should also 'preserve the CFG'.
+  return PreservedAnalyses::none();
+}

test/Transforms/InstSimplify/call.ll

@@ -1,4 +1,5 @@
 ; RUN: opt < %s -instsimplify -S | FileCheck %s
+; RUN: opt < %s -passes=instsimplify -S | FileCheck %s
 
 declare {i8, i1} @llvm.uadd.with.overflow.i8(i8 %a, i8 %b)
 declare {i8, i1} @llvm.usub.with.overflow.i8(i8 %a, i8 %b)