possible pointer-wrap-around concerns, in some cases.
Before this patch, collectConstStridedAccesses (part of interleaved-accesses
analysis) called getPtrStride with [Assume=false, ShouldCheckWrap=true] when
examining all candidate pointers. This is too conservative. Instead, this
patch makes collectConstStridedAccesses use an optimistic approach, calling
getPtrStride with [Assume=true, ShouldCheckWrap=false], and then, once the
candidate interleave groups have been formed, revisits the pointer-wrapping
analysis but only where it matters: namely, in groups that have gaps, and where
the gaps are not at the very end of the group (in which case the loop is
peeled). This second time getPtrStride is called with [Assume=false,
ShouldCheckWrap=true], but this could further be improved to using Assume=true,
once we also add the logic to track that we are not going to meet the scev
runtime checks threshold.
Differential Revision: https://reviews.llvm.org/D25276
llvm-svn: 285517
This removes a couple tablegen classes that become unused after this change. Another class gained an additional parameter to allow PMADDUBSW to specify a different result type from its input type.
llvm-svn: 285515
Summary:
Instead of using the workaround of suppressing the entire index for
modules that call inline asm that may reference locals, use the
NoRename flag on the summary for any locals in the llvm.used set, and
add a reference edge from any functions containing inline asm.
This avoids issues from having no summaries despite the module defining
global values, which was preventing more aggressive index-based
optimization. It will be followed by a subsequent patch to make a
similar fix for local references in module level asm (to fix PR30610).
Reviewers: mehdi_amini
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D26121
llvm-svn: 285513
Summary:
When we have an aliasee that is linkonce, while we can't convert
the non-prevailing copies to available_externally, we still need to
convert the prevailing copy to weak. If a reference to the aliasee
is exported, not converting a copy to weak will result in undefined
references when the linkonce is removed in its original module.
Add a new test and update existing tests.
Reviewers: mehdi_amini
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D26076
llvm-svn: 285512
Summary:
Replace the check of whether a GV has a section with the flag check
in the summary. This is in preparation for using the NoPromote flag
to convey other situations when we can't promote (e.g. locals used in
inline asm).
Reviewers: mehdi_amini
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D26063
llvm-svn: 285507
Try harder to detect obfuscated min/max patterns: the initial pattern was added with D9352 / rL236202.
There was a bug fix for PR27137 at rL264996, but I think we can do better by folding the corresponding
smax pattern and commuted variants.
The codegen tests demonstrate the effect of ValueTracking on the backend via SelectionDAGBuilder. We
can't expose these differences minimally in IR because we don't have smin/smax intrinsics for IR.
Differential Revision: https://reviews.llvm.org/D26091
llvm-svn: 285499
Currently computeKnownBits returns the common known zero/one bits for all elements of vector data, when we may only be interested in one/some of the elements.
This patch adds a DemandedElts argument that allows us to specify the elements we actually care about. The original computeKnownBits implementation calls with a DemandedElts demanding all elements to match current behaviour. Scalar types set this to 1.
The approach was found to be easier than trying to add a per-element known bits solution, for a similar usefulness given the combines where computeKnownBits is typically used.
I've only added support for a few opcodes so far (the ones that have proven straightforward to test), all others will default to demanding all elements but can be updated in due course.
DemandedElts support could similarly be added to computeKnownBitsForTargetNode in a future commit.
This looked like this had caused compile time regressions on some buildbots (and was reverted in rL285381), but appears to have just been a harmless bystander!
Differential Revision: https://reviews.llvm.org/D25691
llvm-svn: 285494
- Fix doxygen file comment
- reduce indentation in loop
- Factor out some common subexpressions
- Move independent helper function out of class
- Fix Changed flag (this is not strictly NFC but a bugfix, but the flag
seems ignored anyway)
llvm-svn: 285488
This resubmits r284436 and r284437, which were reverted in
r284462 as they were breaking the AArch64 buildbot.
The breakage on AArch64 turned out to be a miscompile which is
still not fixed, but is actively tracked at llvm.org/pr30748.
This resubmission re-writes the code in a way so as to make the
miscompile not happen.
llvm-svn: 285483
Instead of asserting that the shift count is != 0 we just bail out
as it's not profitable trying to optimize a node which will be
removed anyway.
Differential Revision: https://reviews.llvm.org/D26098
llvm-svn: 285480
Summary:
Flat instruction can return out of order, so we need always need to wait
for all the outstanding flat operations.
Reviewers: tony-tye, arsenm
Subscribers: kzhuravl, wdng, nhaehnle, llvm-commits, yaxunl
Differential Revision: https://reviews.llvm.org/D25998
llvm-svn: 285479
Also add glc bit to the scalar loads since they exist on VI
and change the caching behavior.
This currently has an assembler bug where the glc bit is incorrectly
accepted on SI/CI which do not have it.
llvm-svn: 285463
While trying to add the glc bit to SMEM instructions on VI
with the new refactoring I ran into some kind of shadowing
problem for the glc operand when using the pseudoinstruction
as a multiclass parameter.
Everywhere that currently uses it defines the operand to have the same
name as its type, i.e. glc:$glc which works. For some reason now it
conflicts, and its up evaluating to the wrong thing. For the
real encoding classes,
let Inst{16} = !if(ps.has_glc, glc, ?); was not being evaluated
and still visible in the Inst initializer in the expanded td file.
In other cases I got a a different error about an illegal operand
where this was using { 0 } initializer from the bits<1> glc initializer
instead of evaluating it as false in the if.
For consistency all of the operand types should probably
be captialized to avoid conflicting with the variable names
unless somebody has a better idea of how to fix this.
llvm-svn: 285462
Summary:
In isel, transform
Num % Den
into
Num - (Num / Den) * Den
if the result of Num / Den is already available.
Reviewers: tra
Subscribers: hfinkel, llvm-commits, jholewinski
Differential Revision: https://reviews.llvm.org/D26090
llvm-svn: 285461
Summary:
This "pass" eagerly creates div and rem instructions even when only one
is needed -- it relies on a later pass (machine DCE?) to clean them up.
This is problematic not just from a cleanliness perspective (this pass
is running during CodeGenPrepare, so should leave the IR in a better
state), but it also creates a problem for instruction selection. If we
always have a div+rem, isel will always select a divrem instruction (if
possible), even when a single div or rem would do.
Specifically, in NVPTX, we want to compute rem from the output of div,
if available. But if a div is not available, we want to leave the rem
alone. This transformation is overeager if div is always available.
Because this code runs as part of CodeGenPrepare, it's nontrivial to
write a test for this change. But this will effectively be tested by
a later patch which adds the aforementioned change to NVPTX isel.
Reviewers: tra
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D26088
llvm-svn: 285460
Summary:
In BypassSlowDivision's short-dividend path, we would create e.g.
udiv exact i32 %a, %b
"exact" here means that we are asserting that %a is a multiple of %b.
But we have no reason to believe this must be true -- this is just a
bug, as far as I can tell.
Reviewers: tra
Subscribers: jholewinski, llvm-commits
Differential Revision: https://reviews.llvm.org/D26097
llvm-svn: 285459
