Revert to pacify a buildbot. rdar://problem/6501862
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@132351 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp b/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp
index b860440..94b619b 100644
--- a/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp
+++ b/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp
@@ -136,26 +136,19 @@
}
}
- // (Y - X) * (-(2**n)) -> (X - Y) * (2**n), for positive nonzero n
- // (Y + const) * (-(2**n)) -> (-constY) * (2**n), for positive nonzero n
- // The "* (2**n)" thus becomes a potential shifting opportunity.
+ // (1 - X) * (-2) -> (x - 1) * 2, for all positive nonzero powers of 2
+ // The "* 2" thus becomes a potential shifting opportunity.
{
const APInt & Val = CI->getValue();
const APInt &PosVal = Val.abs();
if (Val.isNegative() && PosVal.isPowerOf2()) {
- Value *X = 0, *Y = 0;
- ConstantInt *C1 = 0;
- if (Op0->hasOneUse() &&
- (match(Op0, m_Sub(m_Value(Y), m_Value(X)))) ||
- (match(Op0, m_Add(m_Value(Y), m_ConstantInt(C1))))) {
- Value *Sub;
- if (C1) // Matched ADD of constant, negate both operands:
- Sub = Builder->CreateSub(Builder->CreateNeg(C1), Y, "subc");
- else // Matched SUB, swap operands:
- Sub = Builder->CreateSub(X, Y, "suba");
- return
- BinaryOperator::CreateMul(Sub,
- ConstantInt::get(X->getType(), PosVal));
+ Value *X = 0;
+ if (match(Op0, m_Sub(m_One(), m_Value(X)))) {
+ // ConstantInt::get(Op0->getType(), 2);
+ Value *Sub = Builder->CreateSub(X, ConstantInt::get(X->getType(), 1),
+ "dec1");
+ return BinaryOperator::CreateMul(Sub, ConstantInt::get(X->getType(),
+ PosVal));
}
}
}