Bug 89754

Summary:	Vectorizer cost model check should look at evolution of niter in outer loop(s)
Product:	gcc	Reporter:	Richard Biener <rguenth>
Component:	tree-optimization	Assignee:	Not yet assigned to anyone <unassigned>
Status:	NEW ---
Severity:	enhancement	CC:	rsandifo
Priority:	P3	Keywords:	missed-optimization
Version:	9.0
Target Milestone:	---
Host:		Target:
Build:		Known to work:
Known to fail:		Last reconfirmed:	2019-03-18 00:00:00
Bug Depends on:
Bug Blocks:	53947, 87561

Description Richard Biener 2019-03-18 10:01:47 UTC

For the testcase in PR87561 which has a loop nest iterating over a triangle
the vectorizer should take the evolution of the inner loop niter in the outer
loop into account for cost modeling and compute a cost model check for the
outer loop also applying cost model versioning to the outer loop instead of
the inner loop.

Comment 1 Richard Biener 2019-03-18 10:02:23 UTC

If implemented the awkward x86 cost model adjustments might not be neccessary.