[InstCombine] allow (X * C2) << C1 --> X * (C2 << C1) for vectors
This fold already existed for vectors but only when 'C1' was a splat
constant (but 'C2' could be any constant).
There were no tests for any vector constants, so I'm adding a test
that shows non-splat constants for both operands.
llvm-svn: 294650
diff --git a/llvm/lib/Transforms/InstCombine/InstCombineShifts.cpp b/llvm/lib/Transforms/InstCombine/InstCombineShifts.cpp
index ab8ba9e..9aa679c 100644
--- a/llvm/lib/Transforms/InstCombine/InstCombineShifts.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstCombineShifts.cpp
@@ -335,13 +335,6 @@
assert(!Op1C->uge(TypeBits) &&
"Shift over the type width should have been removed already");
- // ((X*C1) << C2) == (X * (C1 << C2))
- if (BinaryOperator *BO = dyn_cast<BinaryOperator>(Op0))
- if (BO->getOpcode() == Instruction::Mul && isLeftShift)
- if (Constant *BOOp = dyn_cast<Constant>(BO->getOperand(1)))
- return BinaryOperator::CreateMul(BO->getOperand(0),
- ConstantExpr::getShl(BOOp, Op1));
-
if (Instruction *FoldedShift = foldOpWithConstantIntoOperand(I))
return FoldedShift;
@@ -604,12 +597,18 @@
}
}
- // (C1 << A) << C2 -> (C1 << C2) << A
- Constant *C1, *C2;
- Value *A;
- if (match(Op0, m_OneUse(m_Shl(m_Constant(C1), m_Value(A)))) &&
- match(Op1, m_Constant(C2)))
- return BinaryOperator::CreateShl(ConstantExpr::getShl(C1, C2), A);
+ Constant *C1;
+ if (match(Op1, m_Constant(C1))) {
+ Constant *C2;
+ Value *X;
+ // (C2 << X) << C1 --> (C2 << C1) << X
+ if (match(Op0, m_OneUse(m_Shl(m_Constant(C2), m_Value(X)))))
+ return BinaryOperator::CreateShl(ConstantExpr::getShl(C2, C1), X);
+
+ // (X * C2) << C1 --> X * (C2 << C1)
+ if (match(Op0, m_Mul(m_Value(X), m_Constant(C2))))
+ return BinaryOperator::CreateMul(X, ConstantExpr::getShl(C2, C1));
+ }
return nullptr;
}