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[VPlan] Initial def-use verification. 

This patch introduces some initial def-use verification. This catches
cases like the one fixed by D129436.

Reviewed By: Ayal

Differential Revision: https://reviews.llvm.org/D129717
This commit is contained in:
Florian Hahn 2022-07-20 11:06:32 +01:00
parent 9fc347aa4e
commit 5124b21648
No known key found for this signature in database
GPG Key ID: EEF712BB5E80EBBA
1 changed files with 62 additions and 4 deletions
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66
llvm/lib/Transforms/Vectorize/VPlanVerifier.cpp
View File

@ -133,7 +133,9 @@ void VPlanVerifier::verifyHierarchicalCFG(
verifyRegionRec(TopRegion);
}
static bool verifyVPBasicBlock(const VPBasicBlock *VPBB) {
static bool
verifyVPBasicBlock(const VPBasicBlock *VPBB,
DenseMap<const VPBlockBase *, unsigned> &BlockNumbering) {
// Verify that phi-like recipes are at the beginning of the block, with no
// other recipes in between.
auto RecipeI = VPBB->begin();
@ -165,15 +167,71 @@ static bool verifyVPBasicBlock(const VPBasicBlock *VPBB) {
RecipeI++;
}
// Verify that defs in VPBB dominate all their uses. The current
// implementation is still incomplete.
DenseMap<const VPRecipeBase *, unsigned> RecipeNumbering;
unsigned Cnt = 0;
for (const VPRecipeBase &R : *VPBB)
RecipeNumbering[&R] = Cnt++;
for (const VPRecipeBase &R : *VPBB) {
for (const VPValue *V : R.definedValues()) {
for (const VPUser *U : V->users()) {
auto *UI = dyn_cast<VPRecipeBase>(U);
if (!UI || isa<VPHeaderPHIRecipe>(UI))
continue;
// If the user is in the same block, check it comes after R in the
// block.
if (UI->getParent() == VPBB) {
if (RecipeNumbering[UI] < RecipeNumbering[&R]) {
errs() << "Use before def!\n";
return false;
}
continue;
}
// Skip blocks outside any region for now and blocks outside
// replicate-regions.
auto *ParentR = VPBB->getParent();
if (!ParentR || !ParentR->isReplicator())
continue;
// For replicators, verify that VPPRedInstPHIRecipe defs are only used
// in subsequent blocks.
if (isa<VPPredInstPHIRecipe>(&R)) {
auto I = BlockNumbering.find(UI->getParent());
unsigned BlockNumber = I == BlockNumbering.end() ? std::numeric_limits<unsigned>::max() : I->second;
if (BlockNumber < BlockNumbering[ParentR]) {
errs() << "Use before def!\n";
return false;
}
continue;
}
// All non-VPPredInstPHIRecipe recipes in the block must be used in
// the replicate region only.
if (UI->getParent()->getParent() != ParentR) {
errs() << "Use before def!\n";
return false;
}
}
}
}
return true;
}
bool VPlanVerifier::verifyPlanIsValid(const VPlan &Plan) {
DenseMap<const VPBlockBase *, unsigned> BlockNumbering;
unsigned Cnt = 0;
auto Iter = depth_first(
VPBlockRecursiveTraversalWrapper<const VPBlockBase *>(Plan.getEntry()));
for (const VPBasicBlock *VPBB :
VPBlockUtils::blocksOnly<const VPBasicBlock>(Iter)) {
if (!verifyVPBasicBlock(VPBB))
for (const VPBlockBase *VPB : Iter) {
BlockNumbering[VPB] = Cnt++;
auto *VPBB = dyn_cast<VPBasicBlock>(VPB);
if (!VPBB)
continue;
if (!verifyVPBasicBlock(VPBB, BlockNumbering))
return false;
}