From 82ef8e19ef1dc06e7dde6a07ed035bf42213af07 Mon Sep 17 00:00:00 2001 From: Omer Paparo Bivas Date: Tue, 1 May 2018 12:25:46 +0000 Subject: [InstCombine] Adjusting bswap pattern matching to hold for And/Shift mixed case Differential Revision: https://reviews.llvm.org/D45731 Change-Id: I85d4226504e954933c41598327c91b2d08192a9d llvm-svn: 331257 --- llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp | 13 ++++++++++++- 1 file changed, 12 insertions(+), 1 deletion(-) (limited to 'llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp') diff --git a/llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp b/llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp index e389af2a2e3..9a5183cf28f 100644 --- a/llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp +++ b/llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp @@ -1675,7 +1675,18 @@ Instruction *InstCombiner::MatchBSwap(BinaryOperator &I) { bool OrOfAnds = match(Op0, m_And(m_Value(), m_Value())) && match(Op1, m_And(m_Value(), m_Value())); - if (!OrOfOrs && !OrOfShifts && !OrOfAnds) + // (A << B) | (C & D) -> bswap if possible. + // The bigger pattern here is ((A & C1) << C2) | ((B >> C2) & C1), which is a + // part of the bswap idiom for specific values of C1, C2 (e.g. C1 = 16711935, + // C2 = 8 for i32). + // This pattern can occur when the operands of the 'or' are not canonicalized + // for some reason (not having only one use, for example). + bool OrOfAndAndSh = (match(Op0, m_LogicalShift(m_Value(), m_Value())) && + match(Op1, m_And(m_Value(), m_Value()))) || + (match(Op0, m_And(m_Value(), m_Value())) && + match(Op1, m_LogicalShift(m_Value(), m_Value()))); + + if (!OrOfOrs && !OrOfShifts && !OrOfAnds && !OrOfAndAndSh) return nullptr; SmallVector Insts; -- cgit v1.2.3