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authorArnold Schwaighofer <aschwaighofer@apple.com>2013-06-27 20:31:06 +0000
committerArnold Schwaighofer <aschwaighofer@apple.com>2013-06-27 20:31:06 +0000
commit0bbbf7cbb063e7d966a764b8cda56f96ad326dc6 (patch)
tree33ff45d8c5e2491619f04d57594c87dbde38993a /lib
parentff4196adcf602cbe0581f3240c3fef0847159550 (diff)
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LoopVectorize: Cache edge masks created during if-conversion
Otherwise, we end up with an exponential IR blowup. Fixes PR16472. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@185097 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'lib')
-rw-r--r--lib/Transforms/Vectorize/LoopVectorize.cpp15
1 files changed, 15 insertions, 0 deletions
diff --git a/lib/Transforms/Vectorize/LoopVectorize.cpp b/lib/Transforms/Vectorize/LoopVectorize.cpp
index 57a44d8..579f20f 100644
--- a/lib/Transforms/Vectorize/LoopVectorize.cpp
+++ b/lib/Transforms/Vectorize/LoopVectorize.cpp
@@ -175,6 +175,11 @@ private:
/// originated from one scalar instruction.
typedef SmallVector<Value*, 2> VectorParts;
+ // When we if-convert we need create edge masks. We have to cache values so
+ // that we don't end up with exponential recursion/IR.
+ typedef DenseMap<std::pair<BasicBlock*, BasicBlock*>,
+ VectorParts> EdgeMaskCache;
+
/// Add code that checks at runtime if the accessed arrays overlap.
/// Returns the comparator value or NULL if no check is needed.
Instruction *addRuntimeCheck(LoopVectorizationLegality *Legal,
@@ -318,6 +323,7 @@ private:
Value *ExtendedIdx;
/// Maps scalars to widened vectors.
ValueMap WidenMap;
+ EdgeMaskCache MaskCache;
};
/// \brief Check if conditionally executed loads are hoistable.
@@ -2166,6 +2172,12 @@ InnerLoopVectorizer::createEdgeMask(BasicBlock *Src, BasicBlock *Dst) {
assert(std::find(pred_begin(Dst), pred_end(Dst), Src) != pred_end(Dst) &&
"Invalid edge");
+ // Look for cached value.
+ std::pair<BasicBlock*, BasicBlock*> Edge(Src, Dst);
+ EdgeMaskCache::iterator ECEntryIt = MaskCache.find(Edge);
+ if (ECEntryIt != MaskCache.end())
+ return ECEntryIt->second;
+
VectorParts SrcMask = createBlockInMask(Src);
// The terminator has to be a branch inst!
@@ -2181,9 +2193,12 @@ InnerLoopVectorizer::createEdgeMask(BasicBlock *Src, BasicBlock *Dst) {
for (unsigned part = 0; part < UF; ++part)
EdgeMask[part] = Builder.CreateAnd(EdgeMask[part], SrcMask[part]);
+
+ MaskCache[Edge] = EdgeMask;
return EdgeMask;
}
+ MaskCache[Edge] = SrcMask;
return SrcMask;
}