minor cleanup to SROA: when lowering type unsafe accesses to
large integers, the first inserted value would always create
an 'or X, 0'. Even though this is trivially zapped by
instcombine, don't bother creating this pointless instruction.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@106979 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Transforms/Scalar/ScalarReplAggregates.cpp b/lib/Transforms/Scalar/ScalarReplAggregates.cpp
index eefcbb4..cae21e9 100644
--- a/lib/Transforms/Scalar/ScalarReplAggregates.cpp
+++ b/lib/Transforms/Scalar/ScalarReplAggregates.cpp
@@ -1655,7 +1655,12 @@
SrcField = BinaryOperator::CreateShl(SrcField, ShiftVal, "", LI);
}
- ResultVal = BinaryOperator::CreateOr(SrcField, ResultVal, "", LI);
+ // Don't create an 'or x, 0' on the first iteration.
+ if (!isa<Constant>(ResultVal) ||
+ !cast<Constant>(ResultVal)->isNullValue())
+ ResultVal = BinaryOperator::CreateOr(SrcField, ResultVal, "", LI);
+ else
+ ResultVal = SrcField;
}
// Handle tail padding by truncating the result