diff options
| -rw-r--r-- | lib/Transforms/Scalar/LoopIdiomRecognize.cpp | 5 | ||||
| -rw-r--r-- | test/Transforms/LoopIdiom/basic.ll | 23 |
2 files changed, 28 insertions, 0 deletions
diff --git a/lib/Transforms/Scalar/LoopIdiomRecognize.cpp b/lib/Transforms/Scalar/LoopIdiomRecognize.cpp index 9878a2e..8c78803 100644 --- a/lib/Transforms/Scalar/LoopIdiomRecognize.cpp +++ b/lib/Transforms/Scalar/LoopIdiomRecognize.cpp @@ -234,6 +234,11 @@ bool LoopIdiomRecognize:: processLoopStoreOfSplatValue(StoreInst *SI, unsigned StoreSize, Value *SplatValue, const SCEVAddRecExpr *Ev, const SCEV *BECount) { + // Verify that the stored value is loop invariant. If not, we can't promote + // the memset. + if (!CurLoop->isLoopInvariant(SplatValue)) + return false; + // Temporarily remove the store from the loop, to avoid the mod/ref query from // seeing it. Instruction *InstAfterStore = ++BasicBlock::iterator(SI); diff --git a/test/Transforms/LoopIdiom/basic.ll b/test/Transforms/LoopIdiom/basic.ll index ef37b1d..ee93cb3 100644 --- a/test/Transforms/LoopIdiom/basic.ll +++ b/test/Transforms/LoopIdiom/basic.ll @@ -91,3 +91,26 @@ for.end: ; preds = %for.body, %entry ; CHECK-TODO: call void @llvm.memset.p0i8.i64(i8* %Base, i8 0, i64 100, i32 1, i1 false) ; CHECK-TODO-NOT: store } + +; This can't be promoted: the memset is a store of a loop variant value. +define void @test5(i8* %Base, i64 %Size) nounwind ssp { +bb.nph: ; preds = %entry + br label %for.body + +for.body: ; preds = %bb.nph, %for.body + %indvar = phi i64 [ 0, %bb.nph ], [ %indvar.next, %for.body ] + %I.0.014 = getelementptr i8* %Base, i64 %indvar + + %V = trunc i64 %indvar to i8 + store i8 %V, i8* %I.0.014, align 1 + %indvar.next = add i64 %indvar, 1 + %exitcond = icmp eq i64 %indvar.next, %Size + br i1 %exitcond, label %for.end, label %for.body + +for.end: ; preds = %for.body, %entry + ret void +; CHECK: @test5 +; CHECK-NOT: memset +; CHECK: ret void +} + |