Currently the SCEVExpander tries to re-use existing casts, even if they
are not exactly at the insertion point it was asked to create the cast.
To do so in some case, it creates a new cast at the insertion point and
updates all users to use the new cast.
This behavior is problematic, because it changes the IR outside of the
instructions created during the expansion. Therefore we cannot
completely undo all changes made during expansion.
This re-use should be only an extra optimization, so only using the new
cast in the expanded instructions should not be a correctness issue.
There are many cases equivalent instructions are created during
expansion.
This patch also adjusts findInsertPointAfter to skip instructions
inserted during expansion. This enables re-using existing casts without
the renaming any uses, by picking a better insertion point.
Reviewed By: efriedma, lebedev.ri
Differential Revision: https://reviews.llvm.org/D84399
The test is quite frafile, as the check lines match IR numbers and it is
not obvious why only a very small subset is checked.
Re-generate check lines, so further changes are more obvious.
As it's causing some bot failures (and per request from kbarton).
This reverts commit r358543/ab70da07286e618016e78247e4a24fcb84077fda.
llvm-svn: 358546
Summary:
The bug was uncovered after fix of PR23384 (part 3 of 3).
The patch restricts pointer multiplication in SCEV computaion for ICmpZero.
Reviewers: qcolombet
Differential Revision: http://reviews.llvm.org/D36170
From: Evgeny Stupachenko <evstupac@gmail.com>
<evgeny.v.stupachenko@intel.com>
llvm-svn: 310092
We try to hoist the insertion point as high as possible to encourage
sharing. However, we must be careful not to hoist into a catchswitch as
it is both an EHPad and a terminator.
llvm-svn: 264344
Florian Hahn