[llvm] r334895 - CorrelatedValuePropagation: Preserve DT.
Michael Zolotukhin via llvm-commits
llvm-commits at lists.llvm.org
Sat Jun 16 11:57:31 PDT 2018
Author: mzolotukhin
Date: Sat Jun 16 11:57:31 2018
New Revision: 334895
URL: http://llvm.org/viewvc/llvm-project?rev=334895&view=rev
Log:
CorrelatedValuePropagation: Preserve DT.
Summary:
We only modify CFG in a couple of places, and we can preserve DT there
with a little effort.
Reviewers: davide, vsk
Subscribers: hiraditya, llvm-commits
Differential Revision: https://reviews.llvm.org/D48059
Modified:
llvm/trunk/lib/Transforms/Scalar/CorrelatedValuePropagation.cpp
llvm/trunk/test/Other/opt-O2-pipeline.ll
llvm/trunk/test/Other/opt-O3-pipeline.ll
llvm/trunk/test/Other/opt-Os-pipeline.ll
Modified: llvm/trunk/lib/Transforms/Scalar/CorrelatedValuePropagation.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Scalar/CorrelatedValuePropagation.cpp?rev=334895&r1=334894&r2=334895&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/Scalar/CorrelatedValuePropagation.cpp (original)
+++ llvm/trunk/lib/Transforms/Scalar/CorrelatedValuePropagation.cpp Sat Jun 16 11:57:31 2018
@@ -82,6 +82,7 @@ namespace {
AU.addRequired<DominatorTreeWrapperPass>();
AU.addRequired<LazyValueInfoWrapperPass>();
AU.addPreserved<GlobalsAAWrapperPass>();
+ AU.addPreserved<DominatorTreeWrapperPass>();
}
};
@@ -306,7 +307,7 @@ static bool processCmp(CmpInst *C, LazyV
/// that cannot fire no matter what the incoming edge can safely be removed. If
/// a case fires on every incoming edge then the entire switch can be removed
/// and replaced with a branch to the case destination.
-static bool processSwitch(SwitchInst *SI, LazyValueInfo *LVI) {
+static bool processSwitch(SwitchInst *SI, LazyValueInfo *LVI, DominatorTree *DT) {
Value *Cond = SI->getCondition();
BasicBlock *BB = SI->getParent();
@@ -321,6 +322,10 @@ static bool processSwitch(SwitchInst *SI
// Analyse each switch case in turn.
bool Changed = false;
+ DenseMap<BasicBlock*, int> SuccessorsCount;
+ for (auto *Succ : successors(BB))
+ SuccessorsCount[Succ]++;
+
for (auto CI = SI->case_begin(), CE = SI->case_end(); CI != CE;) {
ConstantInt *Case = CI->getCaseValue();
@@ -355,7 +360,8 @@ static bool processSwitch(SwitchInst *SI
if (State == LazyValueInfo::False) {
// This case never fires - remove it.
- CI->getCaseSuccessor()->removePredecessor(BB);
+ BasicBlock *Succ = CI->getCaseSuccessor();
+ Succ->removePredecessor(BB);
CI = SI->removeCase(CI);
CE = SI->case_end();
@@ -365,6 +371,8 @@ static bool processSwitch(SwitchInst *SI
++NumDeadCases;
Changed = true;
+ if (--SuccessorsCount[Succ] == 0)
+ DT->deleteEdge(BB, Succ);
continue;
}
if (State == LazyValueInfo::True) {
@@ -381,10 +389,14 @@ static bool processSwitch(SwitchInst *SI
++CI;
}
- if (Changed)
+ if (Changed) {
// If the switch has been simplified to the point where it can be replaced
// by a branch then do so now.
- ConstantFoldTerminator(BB);
+ DeferredDominance DDT(*DT);
+ ConstantFoldTerminator(BB, /*DeleteDeadConditions = */ false,
+ /*TLI = */ nullptr, &DDT);
+ DDT.flush();
+ }
return Changed;
}
@@ -722,7 +734,7 @@ static bool runImpl(Function &F, LazyVal
Instruction *Term = BB->getTerminator();
switch (Term->getOpcode()) {
case Instruction::Switch:
- BBChanged |= processSwitch(cast<SwitchInst>(Term), LVI);
+ BBChanged |= processSwitch(cast<SwitchInst>(Term), LVI, DT);
break;
case Instruction::Ret: {
auto *RI = cast<ReturnInst>(Term);
@@ -767,5 +779,6 @@ CorrelatedValuePropagationPass::run(Func
return PreservedAnalyses::all();
PreservedAnalyses PA;
PA.preserve<GlobalsAA>();
+ PA.preserve<DominatorTreeAnalysis>();
return PA;
}
Modified: llvm/trunk/test/Other/opt-O2-pipeline.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Other/opt-O2-pipeline.ll?rev=334895&r1=334894&r2=334895&view=diff
==============================================================================
--- llvm/trunk/test/Other/opt-O2-pipeline.ll (original)
+++ llvm/trunk/test/Other/opt-O2-pipeline.ll Sat Jun 16 11:57:31 2018
@@ -145,7 +145,6 @@
; CHECK-NEXT: Lazy Value Information Analysis
; CHECK-NEXT: Jump Threading
; CHECK-NEXT: Value Propagation
-; CHECK-NEXT: Dominator Tree Construction
; CHECK-NEXT: Basic Alias Analysis (stateless AA impl)
; CHECK-NEXT: Function Alias Analysis Results
; CHECK-NEXT: Memory Dependence Analysis
Modified: llvm/trunk/test/Other/opt-O3-pipeline.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Other/opt-O3-pipeline.ll?rev=334895&r1=334894&r2=334895&view=diff
==============================================================================
--- llvm/trunk/test/Other/opt-O3-pipeline.ll (original)
+++ llvm/trunk/test/Other/opt-O3-pipeline.ll Sat Jun 16 11:57:31 2018
@@ -149,7 +149,6 @@
; CHECK-NEXT: Lazy Value Information Analysis
; CHECK-NEXT: Jump Threading
; CHECK-NEXT: Value Propagation
-; CHECK-NEXT: Dominator Tree Construction
; CHECK-NEXT: Basic Alias Analysis (stateless AA impl)
; CHECK-NEXT: Function Alias Analysis Results
; CHECK-NEXT: Memory Dependence Analysis
Modified: llvm/trunk/test/Other/opt-Os-pipeline.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Other/opt-Os-pipeline.ll?rev=334895&r1=334894&r2=334895&view=diff
==============================================================================
--- llvm/trunk/test/Other/opt-Os-pipeline.ll (original)
+++ llvm/trunk/test/Other/opt-Os-pipeline.ll Sat Jun 16 11:57:31 2018
@@ -131,7 +131,6 @@
; CHECK-NEXT: Lazy Value Information Analysis
; CHECK-NEXT: Jump Threading
; CHECK-NEXT: Value Propagation
-; CHECK-NEXT: Dominator Tree Construction
; CHECK-NEXT: Basic Alias Analysis (stateless AA impl)
; CHECK-NEXT: Function Alias Analysis Results
; CHECK-NEXT: Memory Dependence Analysis
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