From d5eb1cbee55b60dd7a5745f47c0b46a3a0b952e3 Mon Sep 17 00:00:00 2001 From: Nadav Rotem Date: Fri, 1 Feb 2013 06:45:40 +0000 Subject: Optimize shift lefts of a constant by a value plus constant into a single shift. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@174152 91177308-0d34-0410-b5e6-96231b3b80d8 --- lib/Transforms/InstCombine/InstCombineShifts.cpp | 6 ++++++ 1 file changed, 6 insertions(+) (limited to 'lib/Transforms/InstCombine/InstCombineShifts.cpp') diff --git a/lib/Transforms/InstCombine/InstCombineShifts.cpp b/lib/Transforms/InstCombine/InstCombineShifts.cpp index 8cf76e5e8a..f9e94f225f 100644 --- a/lib/Transforms/InstCombine/InstCombineShifts.cpp +++ b/lib/Transforms/InstCombine/InstCombineShifts.cpp @@ -709,6 +709,12 @@ Instruction *InstCombiner::visitShl(BinaryOperator &I) { match(I.getOperand(1), m_Constant(C2))) return BinaryOperator::CreateShl(ConstantExpr::getShl(C1, C2), A); + // shl (c1 , add(y , c2)) -> (shl (shl(c1, c2)), y) + if (match(I.getOperand(0), m_Constant(C1)) && + match(I.getOperand(1), m_Add(m_Value(A), m_Constant(C2)))) { + return BinaryOperator::CreateShl(ConstantExpr::getShl(C1, C2), A); + } + return 0; } -- cgit v1.2.3