#define DEBUG_TYPE "adce"
#include "llvm/Transforms/Scalar.h"
+#include "llvm/BasicBlock.h"
#include "llvm/Instructions.h"
#include "llvm/Pass.h"
+#include "llvm/Support/CFG.h"
#include "llvm/Support/Compiler.h"
#include "llvm/Support/InstIterator.h"
-#include "llvm/ADT/Statistic.h"
#include "llvm/ADT/DenseSet.h"
+#include "llvm/ADT/DepthFirstIterator.h"
+#include "llvm/ADT/Statistic.h"
#include "llvm/ADT/SmallVector.h"
using namespace llvm;
DenseSet<Instruction*> alive;
SmallVector<Instruction*, 1024> worklist;
+ DenseSet<BasicBlock*> reachable;
+ SmallVector<BasicBlock*, 1024> unreachable;
+
virtual bool runOnFunction(Function& F);
virtual void getAnalysisUsage(AnalysisUsage& AU) const {
bool ADCE::runOnFunction(Function& F) {
alive.clear();
worklist.clear();
+ reachable.clear();
+ unreachable.clear();
+
+ // First, collect the set of reachable blocks ...
+ for (df_iterator<BasicBlock*> DI = df_begin(&F.getEntryBlock()),
+ DE = df_end(&F.getEntryBlock()); DI != DE; ++DI)
+ reachable.insert(*DI);
+
+ // ... and then invert it into the list of unreachable ones. These
+ // blocks will be removed from the function.
+ for (Function::iterator FI = F.begin(), FE = F.end(); FI != FE; ++FI)
+ if (!reachable.count(FI))
+ unreachable.push_back(FI);
+
+ // Prepare to remove blocks by removing the PHI node entries for those blocks
+ // in their successors, and remove them from reference counting.
+ for (SmallVector<BasicBlock*, 1024>::iterator UI = unreachable.begin(),
+ UE = unreachable.end(); UI != UE; ++UI) {
+ BasicBlock* BB = *UI;
+ for (succ_iterator SI = succ_begin(BB), SE = succ_end(BB);
+ SI != SE; ++SI) {
+ BasicBlock* succ = *SI;
+ BasicBlock::iterator succ_inst = succ->begin();
+ while (PHINode* P = dyn_cast<PHINode>(succ_inst)) {
+ P->removeIncomingValue(BB);
+ ++succ_inst;
+ }
+ }
+
+ BB->dropAllReferences();
+ }
+
+ // Finally, erase the unreachable blocks.
+ for (SmallVector<BasicBlock*, 1024>::iterator UI = unreachable.begin(),
+ UE = unreachable.end(); UI != UE; ++UI)
+ (*UI)->eraseFromParent();
// Collect the set of "root" instructions that are known live.
for (inst_iterator I = inst_begin(F), E = inst_end(F); I != E; ++I)
--- /dev/null
+; RUN: llvm-as < %s | opt -adce -simplifycfg | llvm-dis | not grep forcond
+; PR2509
+
+target datalayout = "e-p:32:32:32-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:32:64-f32:32:32-f64:32:64-v64:64:64-v128:128:128-a0:0:64-f80:128:128"
+target triple = "i686-apple-darwin9.3.0"
+@g_3 = external global i8 ; <i8*> [#uses=2]
+
+define i32 @func_1() nounwind {
+entry:
+ br i1 false, label %ifelse, label %ifthen
+
+ifthen: ; preds = %entry
+ br label %ifend
+
+ifelse: ; preds = %entry
+ %tmp3 = load i8* @g_3 ; <i8> [#uses=0]
+ br label %forcond.thread
+
+forcond.thread: ; preds = %ifelse
+ br label %afterfor
+
+forcond: ; preds = %forinc
+ br i1 false, label %afterfor, label %forbody
+
+forbody: ; preds = %forcond
+ br label %forinc
+
+forinc: ; preds = %forbody
+ br label %forcond
+
+afterfor: ; preds = %forcond, %forcond.thread
+ %tmp10 = load i8* @g_3 ; <i8> [#uses=0]
+ br label %ifend
+
+ifend: ; preds = %afterfor, %ifthen
+ ret i32 0
+}