From fb2ea6130ddd318867e3afc23fb7eded64278841 Mon Sep 17 00:00:00 2001 From: Bob Wilson Date: Fri, 29 Jan 2010 22:39:21 +0000 Subject: [PATCH 1/1] Preserve load alignment in instcombine transformations. I've been unable to create a testcase where this matters. The select+load transformation only occurs when isSafeToLoadUnconditionally is true, and in those situations, instcombine also changes the underlying objects to be aligned. This seems like a good idea regardless, and I've verified that it doesn't pessimize the subsequent realignment. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@94850 91177308-0d34-0410-b5e6-96231b3b80d8 --- lib/Transforms/InstCombine/InstCombineLoadStoreAlloca.cpp | 3 +++ 1 file changed, 3 insertions(+) diff --git a/lib/Transforms/InstCombine/InstCombineLoadStoreAlloca.cpp b/lib/Transforms/InstCombine/InstCombineLoadStoreAlloca.cpp index 306ed6728bc..e58c954e917 100644 --- a/lib/Transforms/InstCombine/InstCombineLoadStoreAlloca.cpp +++ b/lib/Transforms/InstCombine/InstCombineLoadStoreAlloca.cpp @@ -117,6 +117,7 @@ static Instruction *InstCombineLoadCast(InstCombiner &IC, LoadInst &LI, // the result of the loaded value. Value *NewLoad = IC.Builder->CreateLoad(CastOp, LI.isVolatile(), CI->getName()); + cast(NewLoad)->setAlignment(LI.getAlignment()); // Now cast the result of the load. return new BitCastInst(NewLoad, LI.getType()); } @@ -205,6 +206,8 @@ Instruction *InstCombiner::visitLoadInst(LoadInst &LI) { SI->getOperand(1)->getName()+".val"); Value *V2 = Builder->CreateLoad(SI->getOperand(2), SI->getOperand(2)->getName()+".val"); + cast(V1)->setAlignment(LI.getAlignment()); + cast(V2)->setAlignment(LI.getAlignment()); return SelectInst::Create(SI->getCondition(), V1, V2); } -- 2.34.1