diff options
| -rw-r--r-- | lib/CodeGen/SelectionDAG/DAGCombiner.cpp | 17 | ||||
| -rw-r--r-- | test/CodeGen/X86/2012-12-1-merge-multiple.ll | 31 |
2 files changed, 46 insertions, 2 deletions
diff --git a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp index 5659069..438e23d 100644 --- a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp +++ b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp @@ -8157,8 +8157,21 @@ SDValue DAGCombiner::visitSTORE(SDNode *N) { // Only perform this optimization before the types are legal, because we // don't want to perform this optimization on every DAGCombine invocation. - if (!LegalTypes && MergeConsecutiveStores(ST)) - return SDValue(N, 0); + if (!LegalTypes) { + bool EverChanged = false; + + do { + // There can be multiple store sequences on the same chain. + // Keep trying to merge store sequences until we are unable to do so + // or until we merge the last store on the chain. + bool Changed = MergeConsecutiveStores(ST); + EverChanged |= Changed; + if (!Changed) break; + } while (ST->getOpcode() != ISD::DELETED_NODE); + + if (EverChanged) + return SDValue(N, 0); + } return ReduceLoadOpStoreWidth(N); } diff --git a/test/CodeGen/X86/2012-12-1-merge-multiple.ll b/test/CodeGen/X86/2012-12-1-merge-multiple.ll new file mode 100644 index 0000000..5931c3d --- /dev/null +++ b/test/CodeGen/X86/2012-12-1-merge-multiple.ll @@ -0,0 +1,31 @@ +; RUN: llc < %s -march=x86-64 -mcpu=corei7 -mtriple=x86_64-pc-win64 | FileCheck %s + +; CHECK: multiple_stores_on_chain +; CHECK: movabsq +; CHECK: movq +; CHECK: movabsq +; CHECK: movq +; CHECK: ret +define void @multiple_stores_on_chain(i16 * %A) { +entry: + %a0 = getelementptr inbounds i16* %A, i64 0 + %a1 = getelementptr inbounds i16* %A, i64 1 + %a2 = getelementptr inbounds i16* %A, i64 2 + %a3 = getelementptr inbounds i16* %A, i64 3 + %a4 = getelementptr inbounds i16* %A, i64 4 + %a5 = getelementptr inbounds i16* %A, i64 5 + %a6 = getelementptr inbounds i16* %A, i64 6 + %a7 = getelementptr inbounds i16* %A, i64 7 + + store i16 0, i16* %a0 + store i16 1, i16* %a1 + store i16 2, i16* %a2 + store i16 3, i16* %a3 + store i16 4, i16* %a4 + store i16 5, i16* %a5 + store i16 6, i16* %a6 + store i16 7, i16* %a7 + + ret void +} + |