When we promote a load of an argument make sure to take the alignment

of the previous load - it's usually important.  For example, we don't want
to blindly turn an unaligned load into an aligned one.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@99699 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Transforms/IPO/ArgumentPromotion.cpp b/lib/Transforms/IPO/ArgumentPromotion.cpp
index 00b147e8851e244d925d06c154300da698564bdb..40a87e880d7bfaeeb102e05571a59b22686c4b73 100644 (file)
--- a/lib/Transforms/IPO/ArgumentPromotion.cpp
+++ b/lib/Transforms/IPO/ArgumentPromotion.cpp
@@ -687,7 +687,11 @@ CallGraphNode *ArgPromotion::DoPromotion(Function *F,
             Ops.clear();
             AA.copyValue(OrigLoad->getOperand(0), V);
           }
-          Args.push_back(new LoadInst(V, V->getName()+".val", Call));
+          // Since we're replacing a load make sure we take the alignment
+          // of the previous load.
+          LoadInst *newLoad = new LoadInst(V, V->getName()+".val", Call);
+          newLoad->setAlignment(OrigLoad->getAlignment());
+          Args.push_back(newLoad);
           AA.copyValue(OrigLoad, Args.back());
         }
       }