diff options
| -rw-r--r-- | lib/Analysis/InstructionSimplify.cpp | 6 | ||||
| -rw-r--r-- | test/Transforms/InstSimplify/2010-12-20-Distribute.ll | 20 |
2 files changed, 26 insertions, 0 deletions
diff --git a/lib/Analysis/InstructionSimplify.cpp b/lib/Analysis/InstructionSimplify.cpp index 1d4ff0fc9e..f737354b36 100644 --- a/lib/Analysis/InstructionSimplify.cpp +++ b/lib/Analysis/InstructionSimplify.cpp @@ -593,6 +593,12 @@ static Value *SimplifySubInst(Value *Op0, Value *Op1, bool isNSW, bool isNUW, match(Op0, m_Add(m_Specific(Op1), m_Value(X)))) return X; + // (X*2) - X -> X + // (X<<1) - X -> X + if (match(Op0, m_Mul(m_Specific(Op1), m_ConstantInt<2>())) || + match(Op0, m_Shl(m_Specific(Op1), m_One()))) + return Op1; + // i1 sub -> xor. if (MaxRecurse && Op0->getType()->isIntegerTy(1)) if (Value *V = SimplifyXorInst(Op0, Op1, TD, DT, MaxRecurse-1)) diff --git a/test/Transforms/InstSimplify/2010-12-20-Distribute.ll b/test/Transforms/InstSimplify/2010-12-20-Distribute.ll index 60cef48446..d20abd68c2 100644 --- a/test/Transforms/InstSimplify/2010-12-20-Distribute.ll +++ b/test/Transforms/InstSimplify/2010-12-20-Distribute.ll @@ -31,6 +31,26 @@ define i32 @factorize3(i32 %x, i32 %a, i32 %b) { ; CHECK: ret i32 %r } +define i32 @factorize4(i32 %x, i32 %y) { +; CHECK: @factorize4 + %sh = shl i32 %y, 1 + %ml = mul i32 %sh, %x + %mr = mul i32 %x, %y + %s = sub i32 %ml, %mr + ret i32 %s +; CHECK: ret i32 %mr +} + +define i32 @factorize5(i32 %x, i32 %y) { +; CHECK: @factorize5 + %sh = mul i32 %y, 2 + %ml = mul i32 %sh, %x + %mr = mul i32 %x, %y + %s = sub i32 %ml, %mr + ret i32 %s +; CHECK: ret i32 %mr +} + define i32 @expand(i32 %x) { ; CHECK: @expand ; ((X & 1) | 2) & 1 -> ((X & 1) & 1) | (2 & 1) -> (X & 1) | 0 -> X & 1 |