[llvm] r333250 - Restore the LoopInstSimplify pass, reverting r327329 that removed it.
Chandler Carruth via llvm-commits
llvm-commits at lists.llvm.org
Thu May 24 18:32:36 PDT 2018
Author: chandlerc
Date: Thu May 24 18:32:36 2018
New Revision: 333250
URL: http://llvm.org/viewvc/llvm-project?rev=333250&view=rev
Log:
Restore the LoopInstSimplify pass, reverting r327329 that removed it.
The plan had always been to move towards using this rather than so much
in-pass simplification within the loop pipeline, but we never got around
to it.... until only a couple months after it was removed due to disuse.
=/
This commit is just a pure revert of the removal. I will add tests and
do some basic cleanup in follow-up commits. Then I'll wire it into the
loop pass pipeline.
Differential Revision: https://reviews.llvm.org/D47353
Added:
llvm/trunk/include/llvm/Transforms/Scalar/LoopInstSimplify.h
llvm/trunk/lib/Transforms/Scalar/LoopInstSimplify.cpp
Modified:
llvm/trunk/include/llvm/InitializePasses.h
llvm/trunk/include/llvm/Transforms/Scalar.h
llvm/trunk/lib/Passes/PassBuilder.cpp
llvm/trunk/lib/Passes/PassRegistry.def
llvm/trunk/lib/Transforms/Scalar/CMakeLists.txt
llvm/trunk/lib/Transforms/Scalar/Scalar.cpp
llvm/trunk/test/Feature/optnone-opt.ll
Modified: llvm/trunk/include/llvm/InitializePasses.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/InitializePasses.h?rev=333250&r1=333249&r2=333250&view=diff
==============================================================================
--- llvm/trunk/include/llvm/InitializePasses.h (original)
+++ llvm/trunk/include/llvm/InitializePasses.h Thu May 24 18:32:36 2018
@@ -215,6 +215,7 @@ void initializeLoopDistributeLegacyPass(
void initializeLoopExtractorPass(PassRegistry&);
void initializeLoopIdiomRecognizeLegacyPassPass(PassRegistry&);
void initializeLoopInfoWrapperPassPass(PassRegistry&);
+void initializeLoopInstSimplifyLegacyPassPass(PassRegistry&);
void initializeLoopInterchangePass(PassRegistry&);
void initializeLoopLoadEliminationPass(PassRegistry&);
void initializeLoopPassPass(PassRegistry&);
Modified: llvm/trunk/include/llvm/Transforms/Scalar.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/Transforms/Scalar.h?rev=333250&r1=333249&r2=333250&view=diff
==============================================================================
--- llvm/trunk/include/llvm/Transforms/Scalar.h (original)
+++ llvm/trunk/include/llvm/Transforms/Scalar.h Thu May 24 18:32:36 2018
@@ -176,6 +176,12 @@ Pass *createLoopUnswitchPass(bool Optimi
//===----------------------------------------------------------------------===//
//
+// LoopInstSimplify - This pass simplifies instructions in a loop's body.
+//
+Pass *createLoopInstSimplifyPass();
+
+//===----------------------------------------------------------------------===//
+//
// LoopUnroll - This pass is a simple loop unrolling pass.
//
Pass *createLoopUnrollPass(int OptLevel = 2, int Threshold = -1, int Count = -1,
Added: llvm/trunk/include/llvm/Transforms/Scalar/LoopInstSimplify.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/Transforms/Scalar/LoopInstSimplify.h?rev=333250&view=auto
==============================================================================
--- llvm/trunk/include/llvm/Transforms/Scalar/LoopInstSimplify.h (added)
+++ llvm/trunk/include/llvm/Transforms/Scalar/LoopInstSimplify.h Thu May 24 18:32:36 2018
@@ -0,0 +1,34 @@
+//===- LoopInstSimplify.h - Loop Inst Simplify Pass -------------*- C++ -*-===//
+//
+// The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This pass performs lightweight instruction simplification on loop bodies.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_TRANSFORMS_SCALAR_LOOPINSTSIMPLIFY_H
+#define LLVM_TRANSFORMS_SCALAR_LOOPINSTSIMPLIFY_H
+
+#include "llvm/Analysis/LoopAnalysisManager.h"
+#include "llvm/IR/PassManager.h"
+
+namespace llvm {
+
+class Loop;
+class LPMUpdater;
+
+/// Performs Loop Inst Simplify Pass.
+class LoopInstSimplifyPass : public PassInfoMixin<LoopInstSimplifyPass> {
+public:
+ PreservedAnalyses run(Loop &L, LoopAnalysisManager &AM,
+ LoopStandardAnalysisResults &AR, LPMUpdater &U);
+};
+
+} // end namespace llvm
+
+#endif // LLVM_TRANSFORMS_SCALAR_LOOPINSTSIMPLIFY_H
Modified: llvm/trunk/lib/Passes/PassBuilder.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Passes/PassBuilder.cpp?rev=333250&r1=333249&r2=333250&view=diff
==============================================================================
--- llvm/trunk/lib/Passes/PassBuilder.cpp (original)
+++ llvm/trunk/lib/Passes/PassBuilder.cpp Thu May 24 18:32:36 2018
@@ -111,6 +111,7 @@
#include "llvm/Transforms/Scalar/LoopDeletion.h"
#include "llvm/Transforms/Scalar/LoopDistribute.h"
#include "llvm/Transforms/Scalar/LoopIdiomRecognize.h"
+#include "llvm/Transforms/Scalar/LoopInstSimplify.h"
#include "llvm/Transforms/Scalar/LoopLoadElimination.h"
#include "llvm/Transforms/Scalar/LoopPassManager.h"
#include "llvm/Transforms/Scalar/LoopPredication.h"
@@ -391,8 +392,9 @@ PassBuilder::buildFunctionSimplification
// FIXME: Currently this is split into two loop pass pipelines because we run
// some function passes in between them. These can and should be replaced by
// loop pass equivalenst but those aren't ready yet. Specifically,
- // `SimplifyCFGPass` and `InstCombinePass` are used. We just have
- // `LoopSimplifyCFGPass` which isn't yet powerful enough.
+ // `SimplifyCFGPass` and `InstCombinePass` are used. We have
+ // `LoopSimplifyCFGPass` which isn't yet powerful enough, and the closest to
+ // the other we have is `LoopInstSimplify`.
LoopPassManager LPM1(DebugLogging), LPM2(DebugLogging);
// Rotate Loop - disable header duplication at -Oz
Modified: llvm/trunk/lib/Passes/PassRegistry.def
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Passes/PassRegistry.def?rev=333250&r1=333249&r2=333250&view=diff
==============================================================================
--- llvm/trunk/lib/Passes/PassRegistry.def (original)
+++ llvm/trunk/lib/Passes/PassRegistry.def Thu May 24 18:32:36 2018
@@ -230,6 +230,7 @@ LOOP_ANALYSIS("ivusers", IVUsersAnalysis
LOOP_PASS("invalidate<all>", InvalidateAllAnalysesPass())
LOOP_PASS("licm", LICMPass())
LOOP_PASS("loop-idiom", LoopIdiomRecognizePass())
+LOOP_PASS("loop-instsimplify", LoopInstSimplifyPass())
LOOP_PASS("rotate", LoopRotatePass())
LOOP_PASS("no-op-loop", NoOpLoopPass())
LOOP_PASS("print", PrintLoopPass(dbgs()))
Modified: llvm/trunk/lib/Transforms/Scalar/CMakeLists.txt
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Scalar/CMakeLists.txt?rev=333250&r1=333249&r2=333250&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/Scalar/CMakeLists.txt (original)
+++ llvm/trunk/lib/Transforms/Scalar/CMakeLists.txt Thu May 24 18:32:36 2018
@@ -28,6 +28,7 @@ add_llvm_library(LLVMScalarOpts
LoopDataPrefetch.cpp
LoopDistribute.cpp
LoopIdiomRecognize.cpp
+ LoopInstSimplify.cpp
LoopInterchange.cpp
LoopLoadElimination.cpp
LoopPassManager.cpp
Added: llvm/trunk/lib/Transforms/Scalar/LoopInstSimplify.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Scalar/LoopInstSimplify.cpp?rev=333250&view=auto
==============================================================================
--- llvm/trunk/lib/Transforms/Scalar/LoopInstSimplify.cpp (added)
+++ llvm/trunk/lib/Transforms/Scalar/LoopInstSimplify.cpp Thu May 24 18:32:36 2018
@@ -0,0 +1,223 @@
+//===- LoopInstSimplify.cpp - Loop Instruction Simplification Pass --------===//
+//
+// The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This pass performs lightweight instruction simplification on loop bodies.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/Transforms/Scalar/LoopInstSimplify.h"
+#include "llvm/ADT/PointerIntPair.h"
+#include "llvm/ADT/STLExtras.h"
+#include "llvm/ADT/SmallPtrSet.h"
+#include "llvm/ADT/SmallVector.h"
+#include "llvm/ADT/Statistic.h"
+#include "llvm/Analysis/AssumptionCache.h"
+#include "llvm/Analysis/InstructionSimplify.h"
+#include "llvm/Analysis/LoopInfo.h"
+#include "llvm/Analysis/LoopPass.h"
+#include "llvm/Analysis/TargetLibraryInfo.h"
+#include "llvm/Analysis/Utils/Local.h"
+#include "llvm/IR/BasicBlock.h"
+#include "llvm/IR/CFG.h"
+#include "llvm/IR/DataLayout.h"
+#include "llvm/IR/Dominators.h"
+#include "llvm/IR/Instruction.h"
+#include "llvm/IR/Instructions.h"
+#include "llvm/IR/Module.h"
+#include "llvm/IR/PassManager.h"
+#include "llvm/IR/User.h"
+#include "llvm/Pass.h"
+#include "llvm/Support/Casting.h"
+#include "llvm/Transforms/Scalar.h"
+#include "llvm/Transforms/Utils/LoopUtils.h"
+#include <algorithm>
+#include <utility>
+
+using namespace llvm;
+
+#define DEBUG_TYPE "loop-instsimplify"
+
+STATISTIC(NumSimplified, "Number of redundant instructions simplified");
+
+static bool SimplifyLoopInst(Loop *L, DominatorTree *DT, LoopInfo *LI,
+ AssumptionCache *AC,
+ const TargetLibraryInfo *TLI) {
+ SmallVector<BasicBlock *, 8> ExitBlocks;
+ L->getUniqueExitBlocks(ExitBlocks);
+ array_pod_sort(ExitBlocks.begin(), ExitBlocks.end());
+
+ SmallPtrSet<const Instruction *, 8> S1, S2, *ToSimplify = &S1, *Next = &S2;
+
+ // The bit we are stealing from the pointer represents whether this basic
+ // block is the header of a subloop, in which case we only process its phis.
+ using WorklistItem = PointerIntPair<BasicBlock *, 1>;
+ SmallVector<WorklistItem, 16> VisitStack;
+ SmallPtrSet<BasicBlock *, 32> Visited;
+
+ bool Changed = false;
+ bool LocalChanged;
+ do {
+ LocalChanged = false;
+
+ VisitStack.clear();
+ Visited.clear();
+
+ VisitStack.push_back(WorklistItem(L->getHeader(), false));
+
+ while (!VisitStack.empty()) {
+ WorklistItem Item = VisitStack.pop_back_val();
+ BasicBlock *BB = Item.getPointer();
+ bool IsSubloopHeader = Item.getInt();
+ const DataLayout &DL = L->getHeader()->getModule()->getDataLayout();
+
+ // Simplify instructions in the current basic block.
+ for (BasicBlock::iterator BI = BB->begin(), BE = BB->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 bother simplifying unused instructions.
+ if (!I->use_empty()) {
+ Value *V = SimplifyInstruction(I, {DL, TLI, DT, AC});
+ if (V && LI->replacementPreservesLCSSAForm(I, V)) {
+ // Mark all uses for resimplification next time round the loop.
+ for (User *U : I->users())
+ Next->insert(cast<Instruction>(U));
+
+ I->replaceAllUsesWith(V);
+ LocalChanged = true;
+ ++NumSimplified;
+ }
+ }
+ if (RecursivelyDeleteTriviallyDeadInstructions(I, TLI)) {
+ // RecursivelyDeleteTriviallyDeadInstruction can remove more than one
+ // instruction, so simply incrementing the iterator does not work.
+ // When instructions get deleted re-iterate instead.
+ BI = BB->begin();
+ BE = BB->end();
+ LocalChanged = true;
+ }
+
+ if (IsSubloopHeader && !isa<PHINode>(I))
+ break;
+ }
+
+ // Add all successors to the worklist, except for loop exit blocks and the
+ // bodies of subloops. We visit the headers of loops so that we can
+ // process
+ // their phis, but we contract the rest of the subloop body and only
+ // follow
+ // edges leading back to the original loop.
+ for (succ_iterator SI = succ_begin(BB), SE = succ_end(BB); SI != SE;
+ ++SI) {
+ BasicBlock *SuccBB = *SI;
+ if (!Visited.insert(SuccBB).second)
+ continue;
+
+ const Loop *SuccLoop = LI->getLoopFor(SuccBB);
+ if (SuccLoop && SuccLoop->getHeader() == SuccBB &&
+ L->contains(SuccLoop)) {
+ VisitStack.push_back(WorklistItem(SuccBB, true));
+
+ SmallVector<BasicBlock *, 8> SubLoopExitBlocks;
+ SuccLoop->getExitBlocks(SubLoopExitBlocks);
+
+ for (unsigned i = 0; i < SubLoopExitBlocks.size(); ++i) {
+ BasicBlock *ExitBB = SubLoopExitBlocks[i];
+ if (LI->getLoopFor(ExitBB) == L && Visited.insert(ExitBB).second)
+ VisitStack.push_back(WorklistItem(ExitBB, false));
+ }
+
+ continue;
+ }
+
+ bool IsExitBlock =
+ std::binary_search(ExitBlocks.begin(), ExitBlocks.end(), SuccBB);
+ if (IsExitBlock)
+ continue;
+
+ VisitStack.push_back(WorklistItem(SuccBB, false));
+ }
+ }
+
+ // Place the list of instructions to simplify on the next loop iteration
+ // into ToSimplify.
+ std::swap(ToSimplify, Next);
+ Next->clear();
+
+ Changed |= LocalChanged;
+ } while (LocalChanged);
+
+ return Changed;
+}
+
+namespace {
+
+class LoopInstSimplifyLegacyPass : public LoopPass {
+public:
+ static char ID; // Pass ID, replacement for typeid
+
+ LoopInstSimplifyLegacyPass() : LoopPass(ID) {
+ initializeLoopInstSimplifyLegacyPassPass(*PassRegistry::getPassRegistry());
+ }
+
+ bool runOnLoop(Loop *L, LPPassManager &LPM) override {
+ if (skipLoop(L))
+ return false;
+ DominatorTreeWrapperPass *DTWP =
+ getAnalysisIfAvailable<DominatorTreeWrapperPass>();
+ DominatorTree *DT = DTWP ? &DTWP->getDomTree() : nullptr;
+ LoopInfo *LI = &getAnalysis<LoopInfoWrapperPass>().getLoopInfo();
+ AssumptionCache *AC =
+ &getAnalysis<AssumptionCacheTracker>().getAssumptionCache(
+ *L->getHeader()->getParent());
+ const TargetLibraryInfo *TLI =
+ &getAnalysis<TargetLibraryInfoWrapperPass>().getTLI();
+
+ return SimplifyLoopInst(L, DT, LI, AC, TLI);
+ }
+
+ void getAnalysisUsage(AnalysisUsage &AU) const override {
+ AU.addRequired<AssumptionCacheTracker>();
+ AU.addRequired<TargetLibraryInfoWrapperPass>();
+ AU.setPreservesCFG();
+ getLoopAnalysisUsage(AU);
+ }
+};
+
+} // end anonymous namespace
+
+PreservedAnalyses LoopInstSimplifyPass::run(Loop &L, LoopAnalysisManager &AM,
+ LoopStandardAnalysisResults &AR,
+ LPMUpdater &) {
+ if (!SimplifyLoopInst(&L, &AR.DT, &AR.LI, &AR.AC, &AR.TLI))
+ return PreservedAnalyses::all();
+
+ auto PA = getLoopPassPreservedAnalyses();
+ PA.preserveSet<CFGAnalyses>();
+ return PA;
+}
+
+char LoopInstSimplifyLegacyPass::ID = 0;
+
+INITIALIZE_PASS_BEGIN(LoopInstSimplifyLegacyPass, "loop-instsimplify",
+ "Simplify instructions in loops", false, false)
+INITIALIZE_PASS_DEPENDENCY(AssumptionCacheTracker)
+INITIALIZE_PASS_DEPENDENCY(LoopPass)
+INITIALIZE_PASS_DEPENDENCY(TargetLibraryInfoWrapperPass)
+INITIALIZE_PASS_END(LoopInstSimplifyLegacyPass, "loop-instsimplify",
+ "Simplify instructions in loops", false, false)
+
+Pass *llvm::createLoopInstSimplifyPass() {
+ return new LoopInstSimplifyLegacyPass();
+}
Modified: llvm/trunk/lib/Transforms/Scalar/Scalar.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Scalar/Scalar.cpp?rev=333250&r1=333249&r2=333250&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/Scalar/Scalar.cpp (original)
+++ llvm/trunk/lib/Transforms/Scalar/Scalar.cpp Thu May 24 18:32:36 2018
@@ -62,6 +62,7 @@ void llvm::initializeScalarOpts(PassRegi
initializeLoopDataPrefetchLegacyPassPass(Registry);
initializeLoopDeletionLegacyPassPass(Registry);
initializeLoopAccessLegacyAnalysisPass(Registry);
+ initializeLoopInstSimplifyLegacyPassPass(Registry);
initializeLoopInterchangePass(Registry);
initializeLoopPredicationLegacyPassPass(Registry);
initializeLoopRotateLegacyPassPass(Registry);
Modified: llvm/trunk/test/Feature/optnone-opt.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Feature/optnone-opt.ll?rev=333250&r1=333249&r2=333250&view=diff
==============================================================================
--- llvm/trunk/test/Feature/optnone-opt.ll (original)
+++ llvm/trunk/test/Feature/optnone-opt.ll Thu May 24 18:32:36 2018
@@ -3,7 +3,7 @@
; RUN: opt -O2 -S -debug %s 2>&1 | FileCheck %s --check-prefix=OPT-O1 --check-prefix=OPT-O2O3
; RUN: opt -O3 -S -debug %s 2>&1 | FileCheck %s --check-prefix=OPT-O1 --check-prefix=OPT-O2O3
; RUN: opt -dce -die -gvn-hoist -loweratomic -S -debug %s 2>&1 | FileCheck %s --check-prefix=OPT-MORE
-; RUN: opt -indvars -licm -loop-deletion -loop-extract -loop-idiom -loop-reduce -loop-reroll -loop-rotate -loop-unroll -loop-unswitch -S -debug %s 2>&1 | FileCheck %s --check-prefix=OPT-LOOP
+; RUN: opt -indvars -licm -loop-deletion -loop-extract -loop-idiom -loop-instsimplify -loop-reduce -loop-reroll -loop-rotate -loop-unroll -loop-unswitch -S -debug %s 2>&1 | FileCheck %s --check-prefix=OPT-LOOP
; REQUIRES: asserts
@@ -67,5 +67,6 @@ attributes #0 = { optnone noinline }
; OPT-LOOP-DAG: Skipping pass 'Recognize loop idioms'
; OPT-LOOP-DAG: Skipping pass 'Reroll loops'
; OPT-LOOP-DAG: Skipping pass 'Rotate Loops'
+; OPT-LOOP-DAG: Skipping pass 'Simplify instructions in loops'
; OPT-LOOP-DAG: Skipping pass 'Unroll loops'
; OPT-LOOP-DAG: Skipping pass 'Unswitch loops'
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