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[PM] Split the AssumptionTracker immutable pass into two separate APIs:

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a cache of assumptions for a single function, and an immutable pass that
manages those caches.

The motivation for this change is two fold. Immutable analyses are
really hacks around the current pass manager design and don't exist in
the new design. This is usually OK, but it requires that the core logic
of an immutable pass be reasonably partitioned off from the pass logic.
This change does precisely that. As a consequence it also paves the way
for the *many* utility functions that deal in the assumptions to live in
both pass manager worlds by creating an separate non-pass object with
its own independent API that they all rely on. Now, the only bits of the
system that deal with the actual pass mechanics are those that actually
need to deal with the pass mechanics.

Once this separation is made, several simplifications become pretty
obvious in the assumption cache itself. Rather than using a set and
callback value handles, it can just be a vector of weak value handles.
The callers can easily skip the handles that are null, and eventually we
can wrap all of this up behind a filter iterator.

For now, this adds boiler plate to the various passes, but this kind of
boiler plate will end up making it possible to port these passes to the
new pass manager, and so it will end up factored away pretty reasonably.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@225131 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Chandler Carruth
2015-01-04 12:03:27 +00:00
parent 07d7dbae9e
commit 5a9cd4d44e
65 changed files with 995 additions and 946 deletions
Download Patch File Download Diff File Expand all files Collapse all files

34
lib/Transforms/Utils/LoopSimplify.cpp
View File

@ -44,7 +44,7 @@
#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/Statistic.h"
#include "llvm/Analysis/AliasAnalysis.h"
#include "llvm/Analysis/AssumptionTracker.h"
#include "llvm/Analysis/AssumptionCache.h"
#include "llvm/Analysis/DependenceAnalysis.h"
#include "llvm/Analysis/InstructionSimplify.h"
#include "llvm/Analysis/LoopInfo.h"
@ -210,11 +210,11 @@ static void addBlockAndPredsToSet(BasicBlock *InputBB, BasicBlock *StopBlock,
/// us how to partition the loops.
static PHINode *findPHIToPartitionLoops(Loop *L, AliasAnalysis *AA,
DominatorTree *DT,
AssumptionTracker *AT) {
AssumptionCache *AC) {
for (BasicBlock::iterator I = L->getHeader()->begin(); isa<PHINode>(I); ) {
PHINode *PN = cast<PHINode>(I);
++I;
if (Value *V = SimplifyInstruction(PN, nullptr, nullptr, DT, AT)) {
if (Value *V = SimplifyInstruction(PN, nullptr, nullptr, DT, AC)) {
// This is a degenerate PHI already, don't modify it!
PN->replaceAllUsesWith(V);
if (AA) AA->deleteValue(PN);
@ -254,7 +254,7 @@ static PHINode *findPHIToPartitionLoops(Loop *L, AliasAnalysis *AA,
static Loop *separateNestedLoop(Loop *L, BasicBlock *Preheader,
AliasAnalysis *AA, DominatorTree *DT,
LoopInfo *LI, ScalarEvolution *SE, Pass *PP,
AssumptionTracker *AT) {
AssumptionCache *AC) {
// Don't try to separate loops without a preheader.
if (!Preheader)
return nullptr;
@ -263,7 +263,7 @@ static Loop *separateNestedLoop(Loop *L, BasicBlock *Preheader,
assert(!L->getHeader()->isLandingPad() &&
"Can't insert backedge to landing pad");
PHINode *PN = findPHIToPartitionLoops(L, AA, DT, AT);
PHINode *PN = findPHIToPartitionLoops(L, AA, DT, AC);
if (!PN) return nullptr; // No known way to partition.
// Pull out all predecessors that have varying values in the loop. This
@ -476,8 +476,8 @@ static BasicBlock *insertUniqueBackedgeBlock(Loop *L, BasicBlock *Preheader,
/// explicit if they accepted the analysis directly and then updated it.
static bool simplifyOneLoop(Loop *L, SmallVectorImpl<Loop *> &Worklist,
AliasAnalysis *AA, DominatorTree *DT, LoopInfo *LI,
ScalarEvolution *SE, Pass *PP,
const DataLayout *DL, AssumptionTracker *AT) {
ScalarEvolution *SE, Pass *PP, const DataLayout *DL,
AssumptionCache *AC) {
bool Changed = false;
ReprocessLoop:
@ -583,8 +583,8 @@ ReprocessLoop:
// this for loops with a giant number of backedges, just factor them into a
// common backedge instead.
if (L->getNumBackEdges() < 8) {
if (Loop *OuterL = separateNestedLoop(L, Preheader, AA, DT, LI, SE,
PP, AT)) {
if (Loop *OuterL =
separateNestedLoop(L, Preheader, AA, DT, LI, SE, PP, AC)) {
++NumNested;
// Enqueue the outer loop as it should be processed next in our
// depth-first nest walk.
@ -614,7 +614,7 @@ ReprocessLoop:
PHINode *PN;
for (BasicBlock::iterator I = L->getHeader()->begin();
(PN = dyn_cast<PHINode>(I++)); )
if (Value *V = SimplifyInstruction(PN, nullptr, nullptr, DT, AT)) {
if (Value *V = SimplifyInstruction(PN, nullptr, nullptr, DT, AC)) {
if (AA) AA->deleteValue(PN);
if (SE) SE->forgetValue(PN);
PN->replaceAllUsesWith(V);
@ -714,7 +714,7 @@ ReprocessLoop:
bool llvm::simplifyLoop(Loop *L, DominatorTree *DT, LoopInfo *LI, Pass *PP,
AliasAnalysis *AA, ScalarEvolution *SE,
const DataLayout *DL, AssumptionTracker *AT) {
const DataLayout *DL, AssumptionCache *AC) {
bool Changed = false;
// Worklist maintains our depth-first queue of loops in this nest to process.
@ -732,7 +732,7 @@ bool llvm::simplifyLoop(Loop *L, DominatorTree *DT, LoopInfo *LI, Pass *PP,
while (!Worklist.empty())
Changed |= simplifyOneLoop(Worklist.pop_back_val(), Worklist, AA, DT, LI,
SE, PP, DL, AT);
SE, PP, DL, AC);
return Changed;
}
@ -751,12 +751,12 @@ namespace {
LoopInfo *LI;
ScalarEvolution *SE;
const DataLayout *DL;
AssumptionTracker *AT;
AssumptionCache *AC;
bool runOnFunction(Function &F) override;
void getAnalysisUsage(AnalysisUsage &AU) const override {
AU.addRequired<AssumptionTracker>();
AU.addRequired<AssumptionCacheTracker>();
// We need loop information to identify the loops...
AU.addRequired<DominatorTreeWrapperPass>();
@ -779,7 +779,7 @@ namespace {
char LoopSimplify::ID = 0;
INITIALIZE_PASS_BEGIN(LoopSimplify, "loop-simplify",
"Canonicalize natural loops", false, false)
INITIALIZE_PASS_DEPENDENCY(AssumptionTracker)
INITIALIZE_PASS_DEPENDENCY(AssumptionCacheTracker)
INITIALIZE_PASS_DEPENDENCY(DominatorTreeWrapperPass)
INITIALIZE_PASS_DEPENDENCY(LoopInfo)
INITIALIZE_PASS_END(LoopSimplify, "loop-simplify",
@ -800,11 +800,11 @@ bool LoopSimplify::runOnFunction(Function &F) {
SE = getAnalysisIfAvailable<ScalarEvolution>();
DataLayoutPass *DLP = getAnalysisIfAvailable<DataLayoutPass>();
DL = DLP ? &DLP->getDataLayout() : nullptr;
AT = &getAnalysis<AssumptionTracker>();
AC = &getAnalysis<AssumptionCacheTracker>().getAssumptionCache(F);
// Simplify each loop nest in the function.
for (LoopInfo::iterator I = LI->begin(), E = LI->end(); I != E; ++I)
Changed |= simplifyLoop(*I, DT, LI, this, AA, SE, DL, AT);
Changed |= simplifyLoop(*I, DT, LI, this, AA, SE, DL, AC);
return Changed;
}