[llvm] r367332 - [GVN] Preserve loop related analysis/canonical forms.
Florian Hahn via llvm-commits
llvm-commits at lists.llvm.org
Tue Jul 30 09:43:39 PDT 2019
Author: fhahn
Date: Tue Jul 30 09:43:39 2019
New Revision: 367332
URL: http://llvm.org/viewvc/llvm-project?rev=367332&view=rev
Log:
[GVN] Preserve loop related analysis/canonical forms.
LoopInfo can be easily preserved by passing it to the functions that
modify the CFG (SplitCriticalEdge and MergeBlockIntoPredecessor.
SplitCriticalEdge also preserves LoopSimplify and LCSSA form when when passing in
LoopInfo. The test case shows that we preserve LoopSimplify and
LoopInfo. Adding addPreservedID(LCSSAID) did not preserve LCSSA for some
reason.
Also I am not sure if it is possible to preserve those in the new pass
manager, as they aren't analysis passes.
Reviewers: reames, hfinkel, davide, jdoerfert
Reviewed By: jdoerfert
Differential Revision: https://reviews.llvm.org/D65137
Added:
llvm/trunk/test/Transforms/GVN/preserve-analysis.ll
Modified:
llvm/trunk/include/llvm/Analysis/CFG.h
llvm/trunk/include/llvm/Transforms/Scalar/GVN.h
llvm/trunk/lib/Analysis/CFG.cpp
llvm/trunk/lib/Transforms/Scalar/GVN.cpp
llvm/trunk/test/Transforms/GVN/PRE/2011-06-01-NonLocalMemdepMiscompile.ll
Modified: llvm/trunk/include/llvm/Analysis/CFG.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/Analysis/CFG.h?rev=367332&r1=367331&r2=367332&view=diff
==============================================================================
--- llvm/trunk/include/llvm/Analysis/CFG.h (original)
+++ llvm/trunk/include/llvm/Analysis/CFG.h Tue Jul 30 09:43:39 2019
@@ -46,6 +46,8 @@ unsigned GetSuccessorNumber(const BasicB
///
bool isCriticalEdge(const Instruction *TI, unsigned SuccNum,
bool AllowIdenticalEdges = false);
+bool isCriticalEdge(const Instruction *TI, const BasicBlock *Succ,
+ bool AllowIdenticalEdges = false);
/// Determine whether instruction 'To' is reachable from 'From', without passing
/// through any blocks in ExclusionSet, returning true if uncertain.
Modified: llvm/trunk/include/llvm/Transforms/Scalar/GVN.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/Transforms/Scalar/GVN.h?rev=367332&r1=367331&r2=367332&view=diff
==============================================================================
--- llvm/trunk/include/llvm/Transforms/Scalar/GVN.h (original)
+++ llvm/trunk/include/llvm/Transforms/Scalar/GVN.h Tue Jul 30 09:43:39 2019
@@ -159,6 +159,7 @@ private:
SetVector<BasicBlock *> DeadBlocks;
OptimizationRemarkEmitter *ORE;
ImplicitControlFlowTracking *ICF;
+ LoopInfo *LI;
ValueTable VN;
Modified: llvm/trunk/lib/Analysis/CFG.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Analysis/CFG.cpp?rev=367332&r1=367331&r2=367332&view=diff
==============================================================================
--- llvm/trunk/lib/Analysis/CFG.cpp (original)
+++ llvm/trunk/lib/Analysis/CFG.cpp Tue Jul 30 09:43:39 2019
@@ -87,11 +87,18 @@ unsigned llvm::GetSuccessorNumber(const
/// with multiple predecessors.
bool llvm::isCriticalEdge(const Instruction *TI, unsigned SuccNum,
bool AllowIdenticalEdges) {
- assert(TI->isTerminator() && "Must be a terminator to have successors!");
assert(SuccNum < TI->getNumSuccessors() && "Illegal edge specification!");
+ return isCriticalEdge(TI, TI->getSuccessor(SuccNum), AllowIdenticalEdges);
+}
+
+bool llvm::isCriticalEdge(const Instruction *TI, const BasicBlock *Dest,
+ bool AllowIdenticalEdges) {
+ assert(TI->isTerminator() && "Must be a terminator to have successors!");
if (TI->getNumSuccessors() == 1) return false;
- const BasicBlock *Dest = TI->getSuccessor(SuccNum);
+ assert(find(predecessors(Dest), TI->getParent()) != pred_end(Dest) &&
+ "No edge between TI's block and Dest.");
+
const_pred_iterator I = pred_begin(Dest), E = pred_end(Dest);
// If there is more than one predecessor, this is a critical edge...
Modified: llvm/trunk/lib/Transforms/Scalar/GVN.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Scalar/GVN.cpp?rev=367332&r1=367331&r2=367332&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/Scalar/GVN.cpp (original)
+++ llvm/trunk/lib/Transforms/Scalar/GVN.cpp Tue Jul 30 09:43:39 2019
@@ -70,6 +70,7 @@
#include "llvm/Support/Compiler.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/raw_ostream.h"
+#include "llvm/Transforms/Utils.h"
#include "llvm/Transforms/Utils/BasicBlockUtils.h"
#include "llvm/Transforms/Utils/Local.h"
#include "llvm/Transforms/Utils/SSAUpdater.h"
@@ -626,6 +627,8 @@ PreservedAnalyses GVN::run(Function &F,
PA.preserve<DominatorTreeAnalysis>();
PA.preserve<GlobalsAA>();
PA.preserve<TargetLibraryAnalysis>();
+ if (LI)
+ PA.preserve<LoopAnalysis>();
return PA;
}
@@ -1976,6 +1979,7 @@ bool GVN::runImpl(Function &F, Assumptio
MD = RunMD;
ImplicitControlFlowTracking ImplicitCFT(DT);
ICF = &ImplicitCFT;
+ this->LI = LI;
VN.setMemDep(MD);
ORE = RunORE;
InvalidBlockRPONumbers = true;
@@ -2335,7 +2339,7 @@ bool GVN::performPRE(Function &F) {
/// the block inserted to the critical edge.
BasicBlock *GVN::splitCriticalEdges(BasicBlock *Pred, BasicBlock *Succ) {
BasicBlock *BB =
- SplitCriticalEdge(Pred, Succ, CriticalEdgeSplittingOptions(DT));
+ SplitCriticalEdge(Pred, Succ, CriticalEdgeSplittingOptions(DT, LI));
if (MD)
MD->invalidateCachedPredecessors();
InvalidBlockRPONumbers = true;
@@ -2350,7 +2354,7 @@ bool GVN::splitCriticalEdges() {
do {
std::pair<Instruction *, unsigned> Edge = toSplit.pop_back_val();
SplitCriticalEdge(Edge.first, Edge.second,
- CriticalEdgeSplittingOptions(DT));
+ CriticalEdgeSplittingOptions(DT, LI));
} while (!toSplit.empty());
if (MD) MD->invalidateCachedPredecessors();
InvalidBlockRPONumbers = true;
@@ -2456,18 +2460,26 @@ void GVN::addDeadBlock(BasicBlock *BB) {
if (DeadBlocks.count(B))
continue;
+ // First, split the critical edges. This might also create additional blocks
+ // to preserve LoopSimplify form and adjust edges accordingly.
SmallVector<BasicBlock *, 4> Preds(pred_begin(B), pred_end(B));
for (BasicBlock *P : Preds) {
if (!DeadBlocks.count(P))
continue;
- if (isCriticalEdge(P->getTerminator(), GetSuccessorNumber(P, B))) {
+ if (llvm::any_of(successors(P),
+ [B](BasicBlock *Succ) { return Succ == B; }) &&
+ isCriticalEdge(P->getTerminator(), B)) {
if (BasicBlock *S = splitCriticalEdges(P, B))
DeadBlocks.insert(P = S);
}
+ }
- for (BasicBlock::iterator II = B->begin(); isa<PHINode>(II); ++II) {
- PHINode &Phi = cast<PHINode>(*II);
+ // Now undef the incoming values from the dead predecessors.
+ for (BasicBlock *P : predecessors(B)) {
+ if (!DeadBlocks.count(P))
+ continue;
+ for (PHINode &Phi : B->phis()) {
Phi.setIncomingValueForBlock(P, UndefValue::get(Phi.getType()));
if (MD)
MD->invalidateCachedPointerInfo(&Phi);
@@ -2556,6 +2568,7 @@ public:
AU.addRequired<AssumptionCacheTracker>();
AU.addRequired<DominatorTreeWrapperPass>();
AU.addRequired<TargetLibraryInfoWrapperPass>();
+ AU.addRequired<LoopInfoWrapperPass>();
if (!NoMemDepAnalysis)
AU.addRequired<MemoryDependenceWrapperPass>();
AU.addRequired<AAResultsWrapperPass>();
@@ -2563,6 +2576,8 @@ public:
AU.addPreserved<DominatorTreeWrapperPass>();
AU.addPreserved<GlobalsAAWrapperPass>();
AU.addPreserved<TargetLibraryInfoWrapperPass>();
+ AU.addPreserved<LoopInfoWrapperPass>();
+ AU.addPreservedID(LoopSimplifyID);
AU.addRequired<OptimizationRemarkEmitterWrapperPass>();
}
Modified: llvm/trunk/test/Transforms/GVN/PRE/2011-06-01-NonLocalMemdepMiscompile.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/GVN/PRE/2011-06-01-NonLocalMemdepMiscompile.ll?rev=367332&r1=367331&r2=367332&view=diff
==============================================================================
--- llvm/trunk/test/Transforms/GVN/PRE/2011-06-01-NonLocalMemdepMiscompile.ll (original)
+++ llvm/trunk/test/Transforms/GVN/PRE/2011-06-01-NonLocalMemdepMiscompile.ll Tue Jul 30 09:43:39 2019
@@ -50,8 +50,14 @@ bb15:
%tmp18 = icmp eq i8 %tmp17, 0
br label %bb19
-; CHECK: bb15:
-; CHECK: %tmp17 = phi i8 [ %tmp17.pre, %bb1.bb15_crit_edge ], [ %tmp8, %bb6 ]
+; CHECK-LABEL: bb6:
+; CHECK: br i1 undef, label %bb15split, label %bb10
+
+; CHECK-LABEL: bb15split: ; preds = %bb6
+; CHECK-NEXT: br label %bb15
+
+; CHECK-LABEL: bb15:
+; CHECK: %tmp17 = phi i8 [ %tmp8, %bb15split ], [ %tmp17.pre, %bb1.bb15_crit_edge ]
bb19: ; preds = %bb15
ret i1 %tmp18
Added: llvm/trunk/test/Transforms/GVN/preserve-analysis.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/GVN/preserve-analysis.ll?rev=367332&view=auto
==============================================================================
--- llvm/trunk/test/Transforms/GVN/preserve-analysis.ll (added)
+++ llvm/trunk/test/Transforms/GVN/preserve-analysis.ll Tue Jul 30 09:43:39 2019
@@ -0,0 +1,56 @@
+; RUN: opt < %s -debug-pass=Structure -indvars -gvn -indvars 2>&1 -S | FileCheck --check-prefix=CHECK --check-prefix=IR %s
+; RUN: opt < %s -debug-pass-manager -passes='require<domtree>,loop(simplify-cfg),gvn,loop(indvars)' 2>&1 -S | FileCheck --check-prefix=NEW-PM --check-prefix=IR %s
+
+; Check CFG-only analysis are preserved by SCCP by running it between 2
+; loop-vectorize runs.
+
+; CHECK: Dominator Tree Construction
+; CHECK: Natural Loop Information
+; CHECK: Canonicalize natural loops
+; CHECK: LCSSA Verifier
+; CHECK: Loop-Closed SSA Form Pass
+; CHECK: Global Value Numbering
+; CHECK-NOT: Dominator Tree Construction
+; CHECK-NOT: Natural Loop Information
+; CHECK-NOT: Canonicalize natural loops
+
+; NEW-PM-DAG: Running analysis: LoopAnalysis on test
+; NEW-PM-DAG: Running analysis: DominatorTreeAnalysis on test
+; NEW-PM: Running pass: GVN on test
+; NEW-PM-NOT: Running analysis: LoopAnalysis on test
+; NEW-PM-NOT: Running analysis: DominatorTreeAnalysis on test
+
+declare i1 @cond()
+declare void @dostuff()
+
+define i32 @test() {
+; IR-LABEL: define i32 @test()
+; IR-LABEL: header:
+; IR: br i1 false, label %then, label %latch
+; IR-LABEL: then:
+; IR-NEXT: call void @dostuff()
+; IR-NEXT: br label %latch
+entry:
+ %res = add i32 1, 10
+ br label %header
+
+header:
+ %iv = phi i32 [ %res, %entry ], [ 0, %latch ]
+ %ic = icmp eq i32 %res, 99
+ br i1 %ic, label %then, label %latch
+
+then:
+ br label %then.2
+
+then.2:
+ call void @dostuff()
+ br label %latch
+
+
+latch:
+ %ec = call i1 @cond()
+ br i1 %ec, label %exit, label %header
+
+exit:
+ ret i32 %iv
+}
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