diff options
| -rw-r--r-- | lib/Transforms/Scalar/LICM.cpp | 13 | ||||
| -rw-r--r-- | test/Transforms/LICM/sinking.ll | 14 |
2 files changed, 26 insertions, 1 deletions
diff --git a/lib/Transforms/Scalar/LICM.cpp b/lib/Transforms/Scalar/LICM.cpp index 5f156dba72..aa842e3183 100644 --- a/lib/Transforms/Scalar/LICM.cpp +++ b/lib/Transforms/Scalar/LICM.cpp @@ -43,6 +43,7 @@ #include "llvm/Analysis/AliasSetTracker.h" #include "llvm/Analysis/Dominators.h" #include "llvm/Analysis/ScalarEvolution.h" +#include "llvm/Transforms/Utils/Local.h" #include "llvm/Transforms/Utils/SSAUpdater.h" #include "llvm/Support/CFG.h" #include "llvm/Support/CommandLine.h" @@ -299,7 +300,7 @@ void LICM::SinkRegion(DomTreeNode *N) { // If this subregion is not in the top level loop at all, exit. if (!CurLoop->contains(BB)) return; - // We are processing blocks in reverse dfo, so process children first... + // We are processing blocks in reverse dfo, so process children first. const std::vector<DomTreeNode*> &Children = N->getChildren(); for (unsigned i = 0, e = Children.size(); i != e; ++i) SinkRegion(Children[i]); @@ -310,6 +311,16 @@ void LICM::SinkRegion(DomTreeNode *N) { for (BasicBlock::iterator II = BB->end(); II != BB->begin(); ) { Instruction &I = *--II; + + // If the instruction is dead, we would try to sink it because it isn't used + // in the loop, instead, just delete it. + if (isInstructionTriviallyDead(&I)) { + ++II; + CurAST->deleteValue(&I); + I.eraseFromParent(); + Changed = true; + continue; + } // Check to see if we can sink this instruction to the exit blocks // of the loop. We can do this if the all users of the instruction are diff --git a/test/Transforms/LICM/sinking.ll b/test/Transforms/LICM/sinking.ll index 11112eb744..68e4b64bf9 100644 --- a/test/Transforms/LICM/sinking.ll +++ b/test/Transforms/LICM/sinking.ll @@ -233,3 +233,17 @@ Out: ; preds = %Loop ; CHECK-NEXT: ret i32 %tmp.6 } +; Should delete, not sink, dead instructions. +define void @test11() { + br label %Loop +Loop: + %dead = getelementptr %Ty* @X2, i64 0, i32 0 + br i1 false, label %Loop, label %Out +Out: + ret void +; CHECK: @test11 +; CHECK: Out: +; CHECK-NEXT: ret void +} + + |