Make MemoryBuiltins aware of TargetLibraryInfo.

[oota-llvm.git] / lib / Transforms / Utils / SimplifyInstructions.cpp

diff --git a/lib/Transforms/Utils/SimplifyInstructions.cpp b/lib/Transforms/Utils/SimplifyInstructions.cpp
index 548bc510248a74722c239481ee77c1b27cfeaaf8..528e6a1e425dcfc230ecea482b315f3d07ed09b0 100644 (file)
--- a/lib/Transforms/Utils/SimplifyInstructions.cpp
+++ b/lib/Transforms/Utils/SimplifyInstructions.cpp
@@ -18,11 +18,15 @@
 #include "llvm/Function.h"
 #include "llvm/Pass.h"
 #include "llvm/Type.h"
+#include "llvm/ADT/DepthFirstIterator.h"
+#include "llvm/ADT/SmallPtrSet.h"
 #include "llvm/ADT/Statistic.h"
 #include "llvm/Analysis/Dominators.h"
 #include "llvm/Analysis/InstructionSimplify.h"
 #include "llvm/Target/TargetData.h"
+#include "llvm/Target/TargetLibraryInfo.h"
 #include "llvm/Transforms/Scalar.h"
+#include "llvm/Transforms/Utils/Local.h"
 using namespace llvm;
 
 STATISTIC(NumSimplified, "Number of redundant instructions removed");
@@ -36,31 +40,58 @@ namespace {
 
     void getAnalysisUsage(AnalysisUsage &AU) const {
       AU.setPreservesCFG();
+      AU.addRequired<TargetLibraryInfo>();
     }
 
     /// runOnFunction - Remove instructions that simplify.
     bool runOnFunction(Function &F) {
-      bool Changed = false;
-      const TargetData *TD = getAnalysisIfAvailable<TargetData>();
       const DominatorTree *DT = getAnalysisIfAvailable<DominatorTree>();
-      for (Function::iterator BB = F.begin(), E = F.end(); BB != E; ++BB)
-        for (BasicBlock::iterator BI = BB->begin(), BE = BB->end(); BI != BE;) {
-          Instruction *I = BI++;
-          if (Value *V = SimplifyInstruction(I, TD, DT)) {
-            I->replaceAllUsesWith(V);
-            I->eraseFromParent();
-            Changed = true;
-            ++NumSimplified;
+      const TargetData *TD = getAnalysisIfAvailable<TargetData>();
+      const TargetLibraryInfo *TLI = &getAnalysis<TargetLibraryInfo>();
+      SmallPtrSet<const Instruction*, 8> S1, S2, *ToSimplify = &S1, *Next = &S2;
+      bool Changed = false;
+
+      do {
+        for (df_iterator<BasicBlock*> DI = df_begin(&F.getEntryBlock()),
+             DE = df_end(&F.getEntryBlock()); DI != DE; ++DI)
+          for (BasicBlock::iterator BI = DI->begin(), BE = DI->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, TD, TLI, DT)) {
+                // Mark all uses for resimplification next time round the loop.
+                for (Value::use_iterator UI = I->use_begin(), UE = I->use_end();
+                     UI != UE; ++UI)
+                  Next->insert(cast<Instruction>(*UI));
+                I->replaceAllUsesWith(V);
+                ++NumSimplified;
+                Changed = true;
+              }
+            Changed |= RecursivelyDeleteTriviallyDeadInstructions(I, TLI);
           }
-        }
+
+        // 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;
     }
   };
 }
 
 char InstSimplifier::ID = 0;
-INITIALIZE_PASS(InstSimplifier, "instsimplify", "Remove redundant instructions",
-                false, false)
+INITIALIZE_PASS_BEGIN(InstSimplifier, "instsimplify",
+                      "Remove redundant instructions", false, false)
+INITIALIZE_PASS_DEPENDENCY(TargetLibraryInfo)
+INITIALIZE_PASS_END(InstSimplifier, "instsimplify",
+                    "Remove redundant instructions", false, false)
 char &llvm::InstructionSimplifierID = InstSimplifier::ID;
 
 // Public interface to the simplify instructions pass.