[PATCH] D78935: [DAGCombine] Move the remaining X86 funnel shift patterns to DAGCombine
Simon Pilgrim via Phabricator via llvm-commits
llvm-commits at lists.llvm.org
Mon Apr 27 09:06:38 PDT 2020
RKSimon created this revision.
RKSimon added reviewers: spatel, craig.topper, deadalnix, xbolva00.
Herald added a subscriber: hiraditya.
Herald added a project: LLVM.
X86 matches several 'shift+xor' funnel shift patterns:
fold (or (srl (srl x1, 1), (xor y, 31)), (shl x0, y)) -> (fshl x0, x1, y)
fold (or (shl (shl x0, 1), (xor y, 31)), (srl x1, y)) -> (fshr x0, x1, y)
fold (or (shl (add x0, x0), (xor y, 31)), (srl x1, y)) -> (fshr x0, x1, y)
These patterns are also what we end up with the proposed expansion changes in D77301 <https://reviews.llvm.org/D77301>.
This patch moves these to DAGCombine's generic MatchFunnelPosNeg.
All existing X86 test cases still pass, and we just have a small codegen change in pr32282.ll.
Repository:
rG LLVM Github Monorepo
https://reviews.llvm.org/D78935
Files:
llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
llvm/lib/Target/X86/X86ISelLowering.cpp
llvm/test/CodeGen/X86/pr32282.ll
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