| commit | b2784ec32837df38e0de7436cbde6dfa7aefacd1 | [log] [tgz] |
|---|---|---|
| author | Hans Wennborg <hans@chromium.org> | Mon Oct 07 15:18:29 2024 +0200 |
| committer | Hans Wennborg <hans@chromium.org> | Mon Oct 07 15:18:29 2024 +0200 |
| tree | 96113020851e2a3accd8554088f7d2f6cd541ae3 | |
| parent | 73c9ad263369ac7350d60b3d3670ea3ed56669cc [diff] |
Revert "[X86] For minsize memset/memcpy, use byte or double-word accesses (#87003)" This caused assertion failures: llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp:7736: SDValue getMemsetValue(SDValue, EVT, SelectionDAG &, const SDLoc &): Assertion `C->getAPIntValue().getBitWidth() == 8' failed. See comment on the PR for a reproducer. > repstosb and repstosd are the same size, but stosd is only done for 0 > because the process of multiplying the constant so that it is copied > across the bytes of the 32-bit number adds extra instructions that cause > the size to increase. For 0, repstosb and repstosd are the same size, > but stosd is only done for 0 because the process of multiplying the > constant so that it is copied across the bytes of the 32-bit number adds > extra instructions that cause the size to increase. For 0, we do not > need to do that at all. > > For memcpy, the same goes, and as a result the minsize check was moved > ahead because a jmp to memcpy encoded takes more bytes than repmovsb. This reverts commit 6de5305b3d7a4a19a29b35d481a8090e2a6d3a7e.
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