Displaying 6 results from an estimated 6 matches for "loopvectorizehint".
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loopvectorizehints
2018 Jun 01
2
[VPlan] about vectorization factor selection
...ToScalarize() don't look cheap, doing such check can speed up vectorization, in particular, for large MaxVFs.
Another minor thing is when force vectorization is enabled and MaxVF > 1, expected cost of VF=2 is computed twice at the moment.
bool ForceVectorization = Hints->getForce() == LoopVectorizeHints::FK_Enabled;
// Ignore scalar width, because the user explicitly wants vectorization.
if (ForceVectorization && MaxVF > 1) {
Width = 2;
Cost = expectedCost(Width).first / (float)Width;
}
for (unsigned i = 2; i <= MaxVF; i *= 2) {
// Notice that the vector loop ne...
2014 Aug 13
2
[LLVMdev] setAlreadyVectorized does not delete obsolete metadata?
I noticed that LoopVectorizeHints::setAlreadyVectorized never deletes old "llvm.loop...." metadata. It just appends more, possibly contradicting the old metadata. E.g., after vectorization, a loop previously marked with llvm.loop.vectorize.width ends up with *two* such annotations, like this:
br i1 %exitcond.1, la...
2020 Jun 24
2
Loop vectorization and unsafe floating point math
Hi llvm-dev!
We are doing some fuzzy testing using C program generators,
and one question that came up when generating a program with
both floating point arithmetic and loop pragmas was;
Is the loop vectorizer really allowed to vectorize a loop when
it can't prove that it is safe to reorder fp math, even if
there is a loop pragma that hints about a preferred width.
When reading here
2013 Oct 23
0
[LLVMdev] [PATCH] Loop Rerolling Pass
...should prevent us from analyzing such loops.
I think what you might be seeing is a bug in LoopVectorizerHints:
/// Mark the loop L as already vectorized by setting the width to 1.
void setAlreadyVectorized(Loop *L)
We should set width *and* unroll to one. Because this is how we use it:
LoopVectorizeHints Hints(L, DisableUnrolling);
if (Hints.Width == 1 && Hints.Unroll == 1) {
DEBUG(dbgs() << "LV: Not vectorizing.\n");
return false;
}
After doing this no vectorized loop should be analyzed again. If not I very much like to know.
http://llvm.org/bugs/sho...
2016 Apr 23
2
if-conversion
Hi,
> On Apr 22, 2016, at 8:27 PM, Hal Finkel via llvm-dev <llvm-dev at lists.llvm.org> wrote:
>
> Hi Rob,
>
> The problem here is that the d[i] array is only conditionally accessed, and so we can't if-convert the loop body. The compiler does not know that d[i] is actually dereferenceable for all i from 0 to 15 (the array might be shorter and p[i] is 0 for i past the end
2018 Feb 06
1
6 separate instances of static getPointerOperand(). Time to consolidate?
What LoopVectorize.cpp has are the following. Each function may have to have a separate consolidation discussion.
I'm bringing up getpointerOperand() since I actually found multiple instances defined/used.
DependenceAnalysis.cpp has isLoadOrStore(). LoopAccessAnalysis.cpp has getAddressSpaceOperand().
I'm sure there are others that might be worth discussing within this thread or a follow