Bjorn Pettersson bcce892345 [DAGCombine] Handle big endian correctly in CombineConsecutiveLoads ... Summary: Found out, at code inspection, that there was a fault in DAGCombiner::CombineConsecutiveLoads for big-endian targets. A BUILD_PAIR is always having the least significant bits of the composite value in element 0. So when we are doing the checks for consecutive loads, for big endian targets, we should check if the load to elt 1 is at the lower address and the load to elt 0 is at the higher address. Normally this bug only resulted in missed oppurtunities for doing the load combine. I guess that in some rare situation it could lead to faulty combines, but I've not seen that happen. Note that this patch actually will trigger load combine for some big endian regression tests. One example is test/CodeGen/PowerPC/anon_aggr.ll where we now get t76: i64,ch = load<LD8[FixedStack-9] instead of t37: i32,ch = load<LD4[FixedStack-10]> t35: i32,ch = load<LD4[FixedStack-9]> t41: i64 = build_pair t37, t35 before legalization. Then the legalization will split the LD8 into two loads, so the end result is the same. That should verify that the transfomation is correct now. Reviewers: niravd, hfinkel Reviewed By: niravd Subscribers: nemanjai, llvm-commits Differential Revision: https://reviews.llvm.org/D40444 llvm-svn: 319771		2017-12-05 14:50:05 +00:00
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llvm	[DAGCombine] Handle big endian correctly in CombineConsecutiveLoads	2017-12-05 14:50:05 +00:00
llvm-c	Use code voice for DIBuilder in LLVM C API	2017-11-04 20:31:20 +00:00