[Polly] Add handling of Top Level Regions
Summary:
My goal is to make the newly added `AllowWholeFunctions` options more usable/powerful.
The changes to ScopBuilder.cpp are exclusively checks to prevent `Region.getExit()` from being dereferenced, since Top Level Regions (TLRs) don't have an exit block.
In ScopDetection's `isValidCFG`, I removed a check that disallowed ReturnInstructions to have return values. This might of course have been intentional, so I would welcome your feedback on this and maybe a small explanation why return values are forbidden. Maybe it can be done but needs more changes elsewhere?
The remaining changes in ScopDetection are simply to consider the AllowWholeFunctions option in more places, i.e. allow TLRs when it is set and once again avoid derefererncing `getExit()` if it doesn't exist.
Finally, in ScopHelper.cpp I extended `polly::isErrorBlock` to handle regions without exit blocks as well: The original check was if a given BasicBlock dominates all predecessors of the exit block. Therefore I do the same for TLRs by regarding all BasicBlocks terminating with a ReturnInst as predecessors of a "virtual" function exit block.
Patch by: Lukas Boehm
Reviewers: philip.pfaffe, grosser, Meinersbur
Reviewed By: grosser
Subscribers: pollydev, llvm-commits, bollu
Tags: #polly
Differential Revision: https://reviews.llvm.org/D33411
llvm-svn: 303790
diff --git a/polly/lib/Analysis/ScopBuilder.cpp b/polly/lib/Analysis/ScopBuilder.cpp
index b7c9c65..8b20756 100644
--- a/polly/lib/Analysis/ScopBuilder.cpp
+++ b/polly/lib/Analysis/ScopBuilder.cpp
@@ -894,12 +894,14 @@
return;
// PHINodes in the SCoP region's exit block are also uses to be checked.
- for (auto &Inst : *S->getRegion().getExit()) {
- if (!isa<PHINode>(Inst))
- break;
+ if (!S->getRegion().isTopLevelRegion()) {
+ for (auto &Inst : *S->getRegion().getExit()) {
+ if (!isa<PHINode>(Inst))
+ break;
- for (auto &Op : Inst.operands())
- verifyUse(S, Op, LI);
+ for (auto &Op : Inst.operands())
+ verifyUse(S, Op, LI);
+ }
}
}
#endif
@@ -917,7 +919,7 @@
// To handle these PHI nodes later we will now model their operands as scalar
// accesses. Note that we do not model anything in the exit block if we have
// an exiting block in the region, as there will not be any splitting later.
- if (!scop->hasSingleExitEdge())
+ if (!R.isTopLevelRegion() && !scop->hasSingleExitEdge())
buildAccessFunctions(*R.getExit(), nullptr,
/* IsExitBlock */ true);
diff --git a/polly/lib/Analysis/ScopDetection.cpp b/polly/lib/Analysis/ScopDetection.cpp
index a5fcc16..d1d6360 100644
--- a/polly/lib/Analysis/ScopDetection.cpp
+++ b/polly/lib/Analysis/ScopDetection.cpp
@@ -578,7 +578,7 @@
return true;
// Return instructions are only valid if the region is the top level region.
- if (isa<ReturnInst>(TI) && !CurRegion.getExit() && TI->getNumOperands() == 0)
+ if (isa<ReturnInst>(TI) && CurRegion.isTopLevelRegion())
return true;
Value *Condition = getConditionFromTerminator(TI);
@@ -1485,13 +1485,14 @@
DEBUG(dbgs() << "Checking region: " << CurRegion.getNameStr() << "\n\t");
- if (CurRegion.isTopLevelRegion()) {
+ if (!AllowFullFunction && CurRegion.isTopLevelRegion()) {
DEBUG(dbgs() << "Top level region is invalid\n");
return false;
}
DebugLoc DbgLoc;
- if (isa<UnreachableInst>(CurRegion.getExit()->getTerminator())) {
+ if (CurRegion.getExit() &&
+ isa<UnreachableInst>(CurRegion.getExit()->getTerminator())) {
DEBUG(dbgs() << "Unreachable in exit\n");
return invalid<ReportUnreachableInExit>(Context, /*Assert=*/true,
CurRegion.getExit(), DbgLoc);
diff --git a/polly/lib/Analysis/ScopInfo.cpp b/polly/lib/Analysis/ScopInfo.cpp
index 4be9338..addb338 100644
--- a/polly/lib/Analysis/ScopInfo.cpp
+++ b/polly/lib/Analysis/ScopInfo.cpp
@@ -4824,11 +4824,17 @@
}
int Scop::getRelativeLoopDepth(const Loop *L) const {
- Loop *OuterLoop =
- L ? R.outermostLoopInRegion(const_cast<Loop *>(L)) : nullptr;
- if (!OuterLoop)
+ if (!L || !R.contains(L))
return -1;
- return L->getLoopDepth() - OuterLoop->getLoopDepth();
+ // outermostLoopInRegion always returns nullptr for top level regions
+ if (R.isTopLevelRegion()) {
+ // LoopInfo's depths start at 1, we start at 0
+ return L->getLoopDepth() - 1;
+ } else {
+ Loop *OuterLoop = R.outermostLoopInRegion(const_cast<Loop *>(L));
+ assert(OuterLoop);
+ return L->getLoopDepth() - OuterLoop->getLoopDepth();
+ }
}
ScopArrayInfo *Scop::getArrayInfoByName(const std::string BaseName) {
diff --git a/polly/lib/Support/ScopHelper.cpp b/polly/lib/Support/ScopHelper.cpp
index d288536..27207ec 100644
--- a/polly/lib/Support/ScopHelper.cpp
+++ b/polly/lib/Support/ScopHelper.cpp
@@ -380,9 +380,15 @@
// Basic blocks that are always executed are not considered error blocks,
// as their execution can not be a rare event.
bool DominatesAllPredecessors = true;
- for (auto Pred : predecessors(R.getExit()))
- if (R.contains(Pred) && !DT.dominates(&BB, Pred))
- DominatesAllPredecessors = false;
+ if (R.isTopLevelRegion()) {
+ for (BasicBlock &I : *R.getEntry()->getParent())
+ if (isa<ReturnInst>(I.getTerminator()) && !DT.dominates(&BB, &I))
+ DominatesAllPredecessors = false;
+ } else {
+ for (auto Pred : predecessors(R.getExit()))
+ if (R.contains(Pred) && !DT.dominates(&BB, Pred))
+ DominatesAllPredecessors = false;
+ }
if (DominatesAllPredecessors)
return false;
diff --git a/polly/test/ScopInfo/full-function.ll b/polly/test/ScopInfo/full-function.ll
index 23790085..b91a517 100644
--- a/polly/test/ScopInfo/full-function.ll
+++ b/polly/test/ScopInfo/full-function.ll
@@ -3,6 +3,7 @@
; RUN: opt %loadPolly -polly-scops -analyze < %s \
; RUN: | FileCheck %s -check-prefix=WITHOUT-FULL
+; FULL: Region: %bb---FunctionExit
; FULL: Statements {
; FULL-NEXT: Stmt_loop_1
; FULL-NEXT: Domain :=
@@ -20,6 +21,7 @@
; FULL-NEXT: [p] -> { Stmt_loop_2[i0] -> MemRef_A[0] };
; FULL-NEXT: }
+; WITHOUT-FULL: Region: %loop.2---%merge
; WITHOUT-FULL: Statements {
; WITHOUT-FULL-NEXT: Stmt_loop_2
; WITHOUT-FULL-NEXT: Domain :=
@@ -30,6 +32,7 @@
; WITHOUT-FULL-NEXT: { Stmt_loop_2[i0] -> MemRef_A[0] };
; WITHOUT-FULL-NEXT: }
+; WITHOUT-FULL: Region: %loop.1---%merge
; WITHOUT-FULL: Statements {
; WITHOUT-FULL-NEXT: Stmt_loop_1
; WITHOUT-FULL-NEXT: Domain :=