diff options
author | Nadav Rotem <nrotem@apple.com> | 2012-08-28 10:01:43 +0000 |
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committer | Nadav Rotem <nrotem@apple.com> | 2012-08-28 10:01:43 +0000 |
commit | 9753f0b9b4ab33919c5010acb6a7b2dc1e875aff (patch) | |
tree | 1b51cc99811cc851fded60ed5ec0f232f06b2929 /lib/Transforms/InstCombine | |
parent | eeba6e83175d7835f3648c30a44c2ca12116d40b (diff) |
Teach InstCombine to canonicalize [SU]div+[AL]shl patterns.
For example:
%1 = lshr i32 %x, 2
%2 = udiv i32 %1, 100
rdar://12182093
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@162743 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'lib/Transforms/InstCombine')
-rw-r--r-- | lib/Transforms/InstCombine/InstCombineMulDivRem.cpp | 20 |
1 files changed, 20 insertions, 0 deletions
diff --git a/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp b/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp index 35a0bbb7614..e104a0a9798 100644 --- a/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp +++ b/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp @@ -462,6 +462,16 @@ Instruction *InstCombiner::visitUDiv(BinaryOperator &I) { } } + // Udiv ((Lshl x, c1) , c2) -> x / (C1 * 1<<C2); + if (Constant *C = dyn_cast<Constant>(Op1)) { + Value *X = 0, *C1 = 0; + if (match(Op0, m_LShr(m_Value(X), m_Value(C1)))) { + uint64_t NC = cast<ConstantInt>(C)->getZExtValue() * + (1<< cast<ConstantInt>(C1)->getZExtValue()); + return BinaryOperator::CreateUDiv(X, ConstantInt::get(I.getType(), NC)); + } + } + // X udiv (C1 << N), where C1 is "1<<C2" --> X >> (N+C2) { const APInt *CI; Value *N; if (match(Op1, m_Shl(m_Power2(CI), m_Value(N))) || @@ -533,6 +543,16 @@ Instruction *InstCombiner::visitSDiv(BinaryOperator &I) { ConstantExpr::getNeg(RHS)); } + // Sdiv ((Ashl x, c1) , c2) -> x / (C1 * 1<<C2); + if (Constant *C = dyn_cast<Constant>(Op1)) { + Value *X = 0, *C1 = 0; + if (match(Op0, m_AShr(m_Value(X), m_Value(C1)))) { + uint64_t NC = cast<ConstantInt>(C)->getZExtValue() * + (1<< cast<ConstantInt>(C1)->getZExtValue()); + return BinaryOperator::CreateSDiv(X, ConstantInt::get(I.getType(), NC)); + } + } + // If the sign bits of both operands are zero (i.e. we can prove they are // unsigned inputs), turn this into a udiv. if (I.getType()->isIntegerTy()) { |