From 16f18ed7b555bce5163f3faafc3da36e4d285897 Mon Sep 17 00:00:00 2001 From: Benjamin Kramer Date: Fri, 29 Apr 2011 08:15:41 +0000 Subject: InstCombine: turn (C1 << A) << C2) into (C1 << C2) << A) Fixes PR9809. llvm-svn: 130485 --- llvm/lib/Transforms/InstCombine/InstCombineShifts.cpp | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) (limited to 'llvm/lib/Transforms') diff --git a/llvm/lib/Transforms/InstCombine/InstCombineShifts.cpp b/llvm/lib/Transforms/InstCombine/InstCombineShifts.cpp index a7f800587bb..8143b257b30 100644 --- a/llvm/lib/Transforms/InstCombine/InstCombineShifts.cpp +++ b/llvm/lib/Transforms/InstCombine/InstCombineShifts.cpp @@ -644,7 +644,14 @@ Instruction *InstCombiner::visitShl(BinaryOperator &I) { return &I; } } - + + // (C1 << A) << C2) -> (C1 << C2) << A) + Constant *C1, *C2; + Value *A; + if (match(I.getOperand(0), m_OneUse(m_Shl(m_Constant(C1), m_Value(A)))) && + match(I.getOperand(1), m_Constant(C2))) + return BinaryOperator::CreateShl(ConstantExpr::getShl(C1, C2), A); + return 0; } -- cgit v1.2.3