[PATCH] D29845: [SelectionDAG] Remove redundant stores more aggressively.
Simon Pilgrim via Phabricator via llvm-commits
llvm-commits at lists.llvm.org
Tue Feb 21 11:22:30 PST 2017
RKSimon added a comment.
In https://reviews.llvm.org/D29845#680213, @efriedma wrote:
> I took a quick look at why `test2` isn't getting optimized on other platforms.
>
> On x86, we end up with a DAG that looks like `store(trunc(zextload(x)), x)`, and the code that looks for redundant stores doesn't try to look through truncate nodes. I'm not sure why the no-op OR isn't getting simplified; maybe something isn't getting added to the worklist.
>
> On PPC, the store isn't dead because it's a big-endian target. We probably need some dedicated optimization before legalization to catch this.
Are there tests that cover the cases in X86/PPC (arm-be?) already or could you add them please? I'd also recommend committing the tests with the current codegen so that this patch can show the diffs.
Repository:
rL LLVM
https://reviews.llvm.org/D29845
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