From b3cf70427eb1e97d9b89ba6e9298c280c8a32c74 Mon Sep 17 00:00:00 2001 From: Hans Wennborg Date: Wed, 12 Feb 2020 15:27:11 +0100 Subject: [CodeGen] Fix the computation of the alignment of split stores. By Clement Courbet! Backported from rG15488ff24b4a --- llvm/lib/CodeGen/CodeGenPrepare.cpp | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-) (limited to 'llvm/lib/CodeGen/CodeGenPrepare.cpp') diff --git a/llvm/lib/CodeGen/CodeGenPrepare.cpp b/llvm/lib/CodeGen/CodeGenPrepare.cpp index 003db39fe5f..7d77664fbf6 100644 --- a/llvm/lib/CodeGen/CodeGenPrepare.cpp +++ b/llvm/lib/CodeGen/CodeGenPrepare.cpp @@ -6857,12 +6857,20 @@ static bool splitMergedValStore(StoreInst &SI, const DataLayout &DL, Value *Addr = Builder.CreateBitCast( SI.getOperand(1), SplitStoreType->getPointerTo(SI.getPointerAddressSpace())); - if ((IsLE && Upper) || (!IsLE && !Upper)) + const bool IsOffsetStore = (IsLE && Upper) || (!IsLE && !Upper); + if (IsOffsetStore) Addr = Builder.CreateGEP( SplitStoreType, Addr, ConstantInt::get(Type::getInt32Ty(SI.getContext()), 1)); + MaybeAlign Alignment(SI.getAlignment()); + if (IsOffsetStore && Alignment) { + // When splitting the store in half, naturally one half will retain the + // alignment of the original wider store, regardless of whether it was + // over-aligned or not, while the other will require adjustment. + Alignment = commonAlignment(Alignment, HalfValBitSize / 8); + } Builder.CreateAlignedStore( - V, Addr, Upper ? SI.getAlignment() / 2 : SI.getAlignment()); + V, Addr, Alignment.hasValue() ? Alignment.getValue().value() : 0); }; CreateSplitStore(LValue, false); -- cgit v1.2.3