[llvm-commits] [llvm] r162751 - in /llvm/trunk: lib/Transforms/InstCombine/InstCombineMulDivRem.cpp test/Transforms/InstCombine/2012-08-28-udiv_ashl.ll

[Duncan Sands]

Hi Benjamin,
> --- llvm/trunk/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp (original)
> +++ llvm/trunk/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp Tue Aug 28 08:08:13 2012
> @@ -464,11 +464,11 @@
>
>     // Udiv ((Lshl x, C1) , C2) ->  x / (C2 * 1<<C1);
>     if (ConstantInt *C2 = dyn_cast<ConstantInt>(Op1)) {
> -    Value *X = 0, *C1 = 0;
> -    if (match(Op0, m_LShr(m_Value(X), m_Value(C1))) && C2->getBitWidth() < 65) {
> -      uint64_t NC = cast<ConstantInt>(C2)->getZExtValue() *
> -                    (1<< cast<ConstantInt>(C1)->getZExtValue());
> -      return BinaryOperator::CreateUDiv(X, ConstantInt::get(I.getType(), NC));
> +    Value *X;
> +    ConstantInt *C1;
> +    if (match(Op0, m_LShr(m_Value(X), m_ConstantInt(C1)))) {
> +      APInt NC = C2->getValue().shl(C1->getZExtValue());

shouldn't this use getLimitedValue just in case?

> +      return BinaryOperator::CreateUDiv(X, Builder->getInt(NC));
>       }
>     }
>
> @@ -545,11 +545,11 @@
>
>     // Sdiv ((Ashl x, C1) , C2) ->  x / (C2 * 1<<C1);
>     if (ConstantInt *C2 = dyn_cast<ConstantInt>(Op1)) {
> -    Value *X = 0, *C1 = 0;
> -    if (match(Op0, m_AShr(m_Value(X), m_Value(C1))) && C2->getBitWidth() < 65) {
> -      uint64_t NC = cast<ConstantInt>(C2)->getZExtValue() *
> -                    (1<< cast<ConstantInt>(C1)->getZExtValue());
> -      return BinaryOperator::CreateSDiv(X, ConstantInt::get(I.getType(), NC));
> +    Value *X;
> +    ConstantInt *C1;
> +    if (match(Op0, m_AShr(m_Value(X), m_ConstantInt(C1)))) {

Likewise.

Ciao, Duncan.

> +      APInt NC = C2->getValue().shl(C1->getZExtValue());
> +      return BinaryOperator::CreateSDiv(X, Builder->getInt(NC));
>       }
>     }