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path: root/lib/Transforms/Utils/BypassSlowDivision.cpp
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Diffstat (limited to 'lib/Transforms/Utils/BypassSlowDivision.cpp')
-rw-r--r--lib/Transforms/Utils/BypassSlowDivision.cpp8
1 files changed, 6 insertions, 2 deletions
diff --git a/lib/Transforms/Utils/BypassSlowDivision.cpp b/lib/Transforms/Utils/BypassSlowDivision.cpp
index df299f673f65..9a6761040bd8 100644
--- a/lib/Transforms/Utils/BypassSlowDivision.cpp
+++ b/lib/Transforms/Utils/BypassSlowDivision.cpp
@@ -448,13 +448,17 @@ bool llvm::bypassSlowDivision(BasicBlock *BB,
DivCacheTy PerBBDivCache;
bool MadeChange = false;
- Instruction* Next = &*BB->begin();
+ Instruction *Next = &*BB->begin();
while (Next != nullptr) {
// We may add instructions immediately after I, but we want to skip over
// them.
- Instruction* I = Next;
+ Instruction *I = Next;
Next = Next->getNextNode();
+ // Ignore dead code to save time and avoid bugs.
+ if (I->hasNUses(0))
+ continue;
+
FastDivInsertionTask Task(I, BypassWidths);
if (Value *Replacement = Task.getReplacement(PerBBDivCache)) {
I->replaceAllUsesWith(Replacement);