diff options
| -rw-r--r-- | llvm/lib/Transforms/Scalar/CorrelatedValuePropagation.cpp | 28 | ||||
| -rw-r--r-- | llvm/test/Transforms/CorrelatedValuePropagation/pr35807.ll | 1 |
2 files changed, 5 insertions, 24 deletions
diff --git a/llvm/lib/Transforms/Scalar/CorrelatedValuePropagation.cpp b/llvm/lib/Transforms/Scalar/CorrelatedValuePropagation.cpp index 07803f6e0c7..535d43cdf9e 100644 --- a/llvm/lib/Transforms/Scalar/CorrelatedValuePropagation.cpp +++ b/llvm/lib/Transforms/Scalar/CorrelatedValuePropagation.cpp @@ -14,7 +14,6 @@ #include "llvm/Transforms/Scalar/CorrelatedValuePropagation.h" #include "llvm/ADT/DepthFirstIterator.h" #include "llvm/ADT/Optional.h" -#include "llvm/ADT/PostOrderIterator.h" #include "llvm/ADT/SmallVector.h" #include "llvm/ADT/Statistic.h" #include "llvm/Analysis/GlobalsModRef.h" @@ -123,8 +122,8 @@ static bool processSelect(SelectInst *S, LazyValueInfo *LVI) { return true; } -static bool processPHI(PHINode *P, LazyValueInfo *LVI, const SimplifyQuery &SQ, - DenseSet<BasicBlock *> &ReachableBlocks) { +static bool processPHI(PHINode *P, LazyValueInfo *LVI, + const SimplifyQuery &SQ) { bool Changed = false; BasicBlock *BB = P->getParent(); @@ -132,18 +131,7 @@ static bool processPHI(PHINode *P, LazyValueInfo *LVI, const SimplifyQuery &SQ, Value *Incoming = P->getIncomingValue(i); if (isa<Constant>(Incoming)) continue; - // If the incoming value is coming from an unreachable block, replace - // it with undef and go on. This is good for two reasons: - // 1) We skip an LVI query for an unreachable block - // 2) We transform the incoming value so that the code below doesn't - // mess around with IR in unreachable blocks. - BasicBlock *IncomingBB = P->getIncomingBlock(i); - if (!ReachableBlocks.count(IncomingBB)) { - P->setIncomingValue(i, UndefValue::get(P->getType())); - continue; - } - - Value *V = LVI->getConstantOnEdge(Incoming, IncomingBB, BB, P); + Value *V = LVI->getConstantOnEdge(Incoming, P->getIncomingBlock(i), BB, P); // Look if the incoming value is a select with a scalar condition for which // LVI can tells us the value. In that case replace the incoming value with @@ -575,14 +563,6 @@ static Constant *getConstantAt(Value *V, Instruction *At, LazyValueInfo *LVI) { static bool runImpl(Function &F, LazyValueInfo *LVI, const SimplifyQuery &SQ) { bool FnChanged = false; - - // Compute reachability from the entry block of this function via an RPO - // walk. We use this information when processing PHIs. - DenseSet<BasicBlock *> ReachableBlocks; - ReversePostOrderTraversal<Function *> RPOT(&F); - for (BasicBlock *BB : RPOT) - ReachableBlocks.insert(BB); - // Visiting in a pre-order depth-first traversal causes us to simplify early // blocks before querying later blocks (which require us to analyze early // blocks). Eagerly simplifying shallow blocks means there is strictly less @@ -597,7 +577,7 @@ static bool runImpl(Function &F, LazyValueInfo *LVI, const SimplifyQuery &SQ) { BBChanged |= processSelect(cast<SelectInst>(II), LVI); break; case Instruction::PHI: - BBChanged |= processPHI(cast<PHINode>(II), LVI, SQ, ReachableBlocks); + BBChanged |= processPHI(cast<PHINode>(II), LVI, SQ); break; case Instruction::ICmp: case Instruction::FCmp: diff --git a/llvm/test/Transforms/CorrelatedValuePropagation/pr35807.ll b/llvm/test/Transforms/CorrelatedValuePropagation/pr35807.ll index 8f72b596d28..a9705caaf3c 100644 --- a/llvm/test/Transforms/CorrelatedValuePropagation/pr35807.ll +++ b/llvm/test/Transforms/CorrelatedValuePropagation/pr35807.ll @@ -25,6 +25,7 @@ define void @patatino() { ; CHECK: bb32: ; CHECK-NEXT: br i1 undef, label [[BB40]], label [[BB24]] ; CHECK: bb40: +; CHECK-NEXT: [[TMP41:%.*]] = phi i64 [ 4, [[BB4]] ], [ [[TMP20]], [[BB14]] ], [ undef, [[BB32]] ] ; CHECK-NEXT: ret void ; br i1 undef, label %bb3, label %bb4 |
