Displaying 4 results from an estimated 4 matches for "m_oneus".
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m_oneuse
2019 Dec 31
3
Any significance for m_OneUse in (X / Y) / Z => X / (Y * Z) ??
Dear All,
The InstCombine pass performs the following transformation.
Z / (X / Y) => (Y * Z) / X
This is performed only when operand Op1 ( (X/Y) in this case) has only one
use in future. The code snippet is shown below.
if (match(Op1, m_OneUse(m_FDiv(m_Value(X), m_Value(Y)))) &&
(!isa<Constant>(Y) || !isa<Constant>(Op0))) {
// Z / (X / Y) => (Y * Z) / X
Value *YZ = Builder.CreateFMulFMF(Y, Op0, &I);
return BinaryOperator::CreateFDivFMF(YZ, X, &I);
}
It would be great if someo...
2020 Jan 03
3
Any significance for m_OneUse in (X / Y) / Z => X / (Y * Z) ??
A couple more general comments:
1. There shouldn't be any correctness issues removing one-use checks (the
transform should be safe independently of use-counts).
2. Ideally, you can remove a m_OneUse() from the code and run 'make check'
or similar, and you will see a regression test failure because we have a
'negative' test to cover that pattern. That should make it clear that the
one-use check is there intentionally and what the effect of removing it is.
We've gotten bette...
2020 Jan 06
2
Any significance for m_OneUse in (X / Y) / Z => X / (Y * Z) ??
...02 PM Sanjay Patel <spatel at rotateright.com>
> wrote:
>
>> A couple more general comments:
>> 1. There shouldn't be any correctness issues removing one-use checks (the
>> transform should be safe independently of use-counts).
>> 2. Ideally, you can remove a m_OneUse() from the code and run 'make
>> check' or similar, and you will see a regression test failure because we
>> have a 'negative' test to cover that pattern. That should make it clear
>> that the one-use check is there intentionally and what the effect of
>> re...
2015 Apr 15
2
[LLVMdev] Instruction combiner multiplication canonicalization
...not overflow property.
Please confirm my understanding.
<File: InstCombineMulDivRem.cpp >
168 Instruction *InstCombiner::visitMul(BinaryOperator &I) {
268 // Canonicalize (X+C1)*CI -> X*CI+C1*CI.
269 {
270 Value *X;
271 Constant *C1;
272 if (match(Op0, m_OneUse(m_Add(m_Value(X), m_Constant(C1))))) {
273 Value *Mul = Builder->CreateMul(C1, Op1);
274 // Only go forward with the transform if C1*CI simplifies to a tidier
275 // constant.
276 if (!match(Mul, m_Mul(m_Value(), m_Value())))
277 return BinaryOpera...