10 Commits

Author SHA1 Message Date
David Green
498f89d188 [LV] Collect dead induction truncates
We currently collect the ICmp and Add from an induction variable,
marking them as dead so that vplan values are not created for them. This
extends that to include any single use trunk from the ICmp, which allows
the Add to more readily be removed too.

This can help with costing vplan nodes, as the ICmp and Add are more
reliably removed and are not double-counted.

Differential Revision: https://reviews.llvm.org/D88873
2020-10-08 08:28:58 +01:00
Sjoerd Meijer
9529597cf4 Recommit #2: "[LV] Induction Variable does not remain scalar under tail-folding."
This was reverted because of a miscompilation. At closer inspection, the
problem was actually visible in a changed llvm regression test too. This
one-line follow up fix/recommit will splat the IV, which is what we are trying
to avoid if unnecessary in general, if tail-folding is requested even if all
users are scalar instructions after vectorisation. Because with tail-folding,
the splat IV will be used by the predicate of the masked loads/stores
instructions. The previous version omitted this, which caused the
miscompilation. The original commit message was:

If tail-folding of the scalar remainder loop is applied, the primary induction
variable is splat to a vector and used by the masked load/store vector
instructions, thus the IV does not remain scalar. Because we now mark
that the IV does not remain scalar for these cases, we don't emit the vector IV
if it is not used. Thus, the vectoriser produces less dead code.

Thanks to Ayal Zaks for the direction how to fix this.
2020-05-13 13:50:09 +01:00
Benjamin Kramer
f936457f80 Revert "Recommit "[LV] Induction Variable does not remain scalar under tail-folding.""
This reverts commit ae45b4dbe73ffde5fe3119835aa947d5a49635ed. It
causes miscompilations, test case on the mailing list.
2020-05-08 14:49:10 +02:00
Sjoerd Meijer
ae45b4dbe7 Recommit "[LV] Induction Variable does not remain scalar under tail-folding."
With 3 llvm regr tests fixed/updated that I had missed.
2020-05-07 11:52:20 +01:00
Sjoerd Meijer
20d67ffeae Revert "[LV] Induction Variable does not remain scalar under tail-folding."
This reverts commit 617aa64c84146468b384453375d1d34f97eb57db.

while I investigate buildbot failures.
2020-05-07 09:29:56 +01:00
Sjoerd Meijer
617aa64c84 [LV] Induction Variable does not remain scalar under tail-folding.
If tail-folding of the scalar remainder loop is applied, the primary induction
variable is splat to a vector and used by the masked load/store vector
instructions, thus the IV does not remain scalar. Because we now mark
that the IV does not remain scalar for these cases, we don't emit the vector IV
if it is not used. Thus, the vectoriser produces less dead code.

Thanks to Ayal Zaks for the direction how to fix this.

Differential Revision: https://reviews.llvm.org/D78911
2020-05-07 09:15:23 +01:00
Eric Christopher
cee313d288 Revert "Temporarily Revert "Add basic loop fusion pass.""
The reversion apparently deleted the test/Transforms directory.

Will be re-reverting again.

llvm-svn: 358552
2019-04-17 04:52:47 +00:00
Eric Christopher
a863435128 Temporarily Revert "Add basic loop fusion pass."
As it's causing some bot failures (and per request from kbarton).

This reverts commit r358543/ab70da07286e618016e78247e4a24fcb84077fda.

llvm-svn: 358546
2019-04-17 02:12:23 +00:00
Evgeny Stupachenko
579507a53a Revert r325687 (workaround for PR36032).
Summary:
Revert r325687 workaround for PR36032 since
 a fix was committed in r326154.

Reviewers: sbaranga

Differential Revision: http://reviews.llvm.org/D44768

From: Evgeny Stupachenko <evstupac@gmail.com>
                         <evgeny.v.stupachenko@intel.com>
llvm-svn: 328257
2018-03-22 22:04:39 +00:00
Andrei Elovikov
8b8253fdc7 [LV] Let recordVectorLoopValueForInductionCast to check if IV was created from the cast.
Summary:
It turned out to be error-prone to expect the callers to handle that - better to
leave the decision to this routine and make the required data to be explicitly
passed to the function.

This handles the case that was missed in the r322473 and fixes the assert
mentioned in PR36524.

Reviewers: dorit, mssimpso, Ayal, dcaballe

Reviewed By: dcaballe

Subscribers: Ka-Ka, hiraditya, dneilson, hsaito, llvm-commits

Differential Revision: https://reviews.llvm.org/D43812

llvm-svn: 327960
2018-03-20 09:04:39 +00:00