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Remove the ability for ADCE to remove unreachable blocks in loop nests, because, as Eli pointed out, SimplifyCFG already does this.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@53104 91177308-0d34-0410-b5e6-96231b3b80d8
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@ -53,44 +53,6 @@ bool ADCE::runOnFunction(Function& F) {
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SmallPtrSet<Instruction*, 128> alive;
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SmallVector<Instruction*, 128> worklist;
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SmallPtrSet<BasicBlock*, 64> reachable;
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SmallVector<BasicBlock*, 16> unreachable;
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// First, collect the set of reachable blocks ...
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for (df_ext_iterator<BasicBlock*, SmallPtrSet<BasicBlock*, 64> >
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DI = df_ext_begin(&F.getEntryBlock(), reachable),
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DE = df_ext_end(&F.getEntryBlock(), reachable); DI != DE; ++DI)
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; // Deliberately empty, df_ext_iterator will fill in the set.
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// ... and then invert it into the list of unreachable ones. These
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// blocks will be removed from the function.
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for (Function::iterator FI = F.begin(), FE = F.end(); FI != FE; ++FI)
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if (!reachable.count(FI))
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unreachable.push_back(FI);
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// Prepare to remove blocks by removing the PHI node entries for those blocks
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// in their successors, and remove them from reference counting.
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for (SmallVector<BasicBlock*, 16>::iterator UI = unreachable.begin(),
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UE = unreachable.end(); UI != UE; ++UI) {
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BasicBlock* BB = *UI;
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for (succ_iterator SI = succ_begin(BB), SE = succ_end(BB);
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SI != SE; ++SI) {
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BasicBlock* succ = *SI;
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BasicBlock::iterator succ_inst = succ->begin();
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while (PHINode* P = dyn_cast<PHINode>(succ_inst)) {
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P->removeIncomingValue(BB);
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++succ_inst;
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}
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}
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BB->dropAllReferences();
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}
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// Finally, erase the unreachable blocks.
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for (SmallVector<BasicBlock*, 16>::iterator UI = unreachable.begin(),
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UE = unreachable.end(); UI != UE; ++UI)
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(*UI)->eraseFromParent();
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// Collect the set of "root" instructions that are known live.
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for (inst_iterator I = inst_begin(F), E = inst_end(F); I != E; ++I)
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if (isa<TerminatorInst>(I.getInstructionIterator()) ||
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@ -1,37 +0,0 @@
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; RUN: llvm-as < %s | opt -adce -simplifycfg | llvm-dis | not grep forcond
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; PR2509
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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"
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target triple = "i686-apple-darwin9.3.0"
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@g_3 = external global i8 ; <i8*> [#uses=2]
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define i32 @func_1() nounwind {
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entry:
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br i1 false, label %ifelse, label %ifthen
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ifthen: ; preds = %entry
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br label %ifend
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ifelse: ; preds = %entry
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%tmp3 = load i8* @g_3 ; <i8> [#uses=0]
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br label %forcond.thread
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forcond.thread: ; preds = %ifelse
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br label %afterfor
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forcond: ; preds = %forinc
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br i1 false, label %afterfor, label %forbody
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forbody: ; preds = %forcond
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br label %forinc
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forinc: ; preds = %forbody
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br label %forcond
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afterfor: ; preds = %forcond, %forcond.thread
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%tmp10 = load i8* @g_3 ; <i8> [#uses=0]
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br label %ifend
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ifend: ; preds = %afterfor, %ifthen
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ret i32 0
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}
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