The default assumes that a 16-bit signed offset is used.
LDS instruction use a 16-bit unsigned offset, so it wasn't
being used in some cases where it was assumed a negative offset
could be used.
More should be done here, but first isLegalAddressingMode needs
to gain an addressing mode argument. For now, copy most of the rest
of the default implementation with the immediate offset change.
llvm-svn: 215732
In a previous iteration of the pass, we would try to compensate for
writeback by updating later instructions and/or inserting a SUBS to
reset the base register if necessary.
Since such a SUBS sets the condition flags it's not generally safe to do
this. For now, only merge LDR/STRs if there is no writeback to the base
register (LDM that loads into the base register) or the base register is
killed by one of the merged instructions. These cases are clear wins
both in terms of instruction count and performance.
Also add three new test cases, and update the existing ones accordingly.
llvm-svn: 215729
This adds some code back that was deleted in r92053. The location of the
last merged memory operation needs to be kept up-to-date since MemOps
may be in a different order to the original instruction stream to
allow merging (since registers need to be in ascending order). Also
simplify the logic to determine BaseKill using findRegisterUseOperandIdx
to use an equivalent function call instead.
llvm-svn: 215728
We actually need to return the register into which we materialized the constant
and not just "true" for success. This code is currently partially dead, that is
why it didn't trigger any failures yet. Once I change the order of the constant
materialization this code will be fully exercised.
llvm-svn: 215727
the new shuffle lowering and an implementation for v4 shuffles.
This allows us to handle non-half-crossing shuffles directly for v4
shuffles, both integer and floating point. This currently misses places
where we could perform the blend via UNPCK instructions, but otherwise
generates equally good or better code for the test cases included to the
existing vector shuffle lowering. There are a few cases that are
entertainingly better. ;]
llvm-svn: 215702
BLENDPS, BLENDPD, and PBLENDW instructions into pretty shuffle comments.
These will be used in my next commit as part of test cases for AVX
shuffles which can directly use blend in more places.
llvm-svn: 215701
These are system-only instructions for CPUs with virtualization
extensions, allowing a hypervisor easy access to all of the various
different AArch32 registers.
rdar://problem/17861345
llvm-svn: 215700
target-specific shuffl DAG combines.
We were recognizing the paired shuffles backwards. This code needs to be
replaced anyways as we have the same functionality elsewhere, but I'll
do the refactoring in a follow-up, this is the minimal fix to the
behavior.
In addition to fixing miscompiles with the new vector shuffle lowering,
it also causes the canonicalization to kick in much better, selecting
the smaller encoding variants in lots of places in the new AVX path.
This still isn't quite ideal as we don't need both the shufpd and the
punpck instructions, but that'll get fixed in a follow-up patch.
llvm-svn: 215690
broken logic for merging shuffle masks in the face of SM_SentinelZero
mask operands.
While these are '-1' they don't mean 'undef' the way '-1' means in the
pre-legalized shuffle masks. Instead, they mean that the shuffle
operation is forcibly zeroing that lane. Reflect this and explicitly
handle it in a bunch of places. In one place the effect is equivalent
but much more clear. In the rest it was really weirdly broken.
Also, rewrite the entire merging thing to be a more directy operation
with a single loop and just doing math to map the indices through the
various masks.
Also add a bunch of asserts to try to make in extremely clear what the
different masks can possibly look like.
Finally, add some comments to clarify that we're merging shuffle masks
*up* here rather than *down* as we do everywhere else, and thus the
logic is quite confusing.
Thanks to several different people for sending test cases, and for
Robert Khasanov for an initial attempt at fixing.
llvm-svn: 215687
The LDinto_toc pattern has been part of 64-bit PowerPC for a long
time, and represents loading from a memory location into the TOC
register (X2). However, this pattern doesn't explicitly record that
it modifies that register. This patch adds the missing dependency.
It was very surprising to me that this has never shown up as a problem
in the past, and that we only saw this problem recently in a single
scenario when building a self-hosted clang. It turns out that in most
cases we have another dependency present that keeps the LDinto_toc
instruction tied in place. LDinto_toc is used for TOC restore
following a call site, so this is a typical sequence:
BCTRL8 <regmask>, %CTR8<imp-use>, %RM<imp-use>, %X3<imp-use>, %X12<imp-use>, %X1<imp-def>, ...
LDinto_toc 24, %X1
ADJCALLSTACKUP 96, 0, %R1<imp-def>, %R1<imp-use>
Because the LDinto_toc is inserted prior to the ADJCALLSTACKUP, there
is a natural anti-dependency between the two that keeps it in place.
Therefore we don't usually see a problem. However, in one particular
case, one call is followed immediately by another call, and the second
call requires a parameter that is a TOC-relative address. This is the
code sequence:
BCTRL8 <regmask>, %CTR8<imp-use>, %RM<imp-use>, %X3<imp-use>, %X4<imp-use>, %X5<imp-use>, %X12<imp-use>, %X1<imp-def>, ...
LDinto_toc 24, %X1
ADJCALLSTACKUP 96, 0, %R1<imp-def>, %R1<imp-use>
ADJCALLSTACKDOWN 96, %R1<imp-def>, %R1<imp-use>
%vreg39<def> = ADDIStocHA %X2, <ga:@.str>; G8RC_and_G8RC_NOX0:%vreg39
%vreg40<def> = ADDItocL %vreg39<kill>, <ga:@.str>; G8RC:%vreg40 G8RC_and_G8RC_NOX0:%vreg39
Note that the back-to-back stack adjustments are the same size! The
back end is smart enough to recognize this and optimize them away:
BCTRL8 <regmask>, %CTR8<imp-use>, %RM<imp-use>, %X3<imp-use>, %X4<imp-use>, %X5<imp-use>, %X12<imp-use>, %X1<imp-def>, ...
LDinto_toc 24, %X1
%vreg39<def> = ADDIStocHA %X2, <ga:@.str>; G8RC_and_G8RC_NOX0:%vreg39
%vreg40<def> = ADDItocL %vreg39<kill>, <ga:@.str>; G8RC:%vreg40 G8RC_and_G8RC_NOX0:%vreg39
Now there is nothing to prevent the ADDIStocHA instruction from moving
ahead of the LDinto_toc instruction, and because of the longest-path
heuristic, this is what happens.
With the accompanying patch, %X2 is represented as an implicit def:
BCTRL8 <regmask>, %CTR8<imp-use>, %RM<imp-use>, %X3<imp-use>, %X4<imp-use>, %X5<imp-use>, %X12<imp-use>, %X1<imp-def>, ...
LDinto_toc 24, %X1, %X2<imp-def,dead>
ADJCALLSTACKUP 96, 0, %R1<imp-def,dead>, %R1<imp-use>
ADJCALLSTACKDOWN 96, %R1<imp-def,dead>, %R1<imp-use>
%vreg39<def> = ADDIStocHA %X2, <ga:@.str>; G8RC_and_G8RC_NOX0:%vreg39
%vreg40<def> = ADDItocL %vreg39<kill>, <ga:@.str>; G8RC:%vreg40 G8RC_and_G8RC_NOX0:%vreg39
So now when the two stack adjustments are removed, ADDIStocHA is
prevented from being moved above LDinto_toc.
I have not yet created a test case for this, because the original
failure occurs on a relatively large function that needs reduction.
However, this is a fairly serious bug, despite its infrequency, and I
wanted to get this patch onto the list as soon as possible so that it
can be considered for a 3.5 backport. I'll work on whittling down a
test case.
Have we missed the boat for 3.5 at this point?
Thanks,
Bill
llvm-svn: 215685
FastEmit_i won't always succeed to materialize an i32 constant and just fail.
This would trigger a fall-back to SelectionDAG, which is really not necessary.
This fix will first fall-back to a constant pool load to materialize the constant
before giving up for good.
This fixes <rdar://problem/18022633>.
llvm-svn: 215682
When a call site with noalias metadata is inlined, that metadata can be
propagated directly to the inlined instructions (only those that might access
memory because it is not useful on the others). Prior to inlining, the noalias
metadata could express that a call would not alias with some other memory
access, which implies that no instruction within that called function would
alias. By propagating the metadata to the inlined instructions, we preserve
that knowledge.
This should complete the enhancements requested in PR20500.
llvm-svn: 215676
This reverts:
r215595 "[FastISel][X86] Add large code model support for materializing floating-point constants."
r215594 "[FastISel][X86] Use XOR to materialize the "0" value."
r215593 "[FastISel][X86] Emit more efficient instructions for integer constant materialization."
r215591 "[FastISel][AArch64] Make use of the zero register when possible."
r215588 "[FastISel] Let the target decide first if it wants to materialize a constant."
r215582 "[FastISel][AArch64] Cleanup constant materialization code. NFCI."
llvm-svn: 215673
No functional change. This will be used by the new FMA intrinsic lowering
code.
We can probably add NO_EXC here as well, I am just not too familiar with this
part of AVX512 yet. We can add that later.
llvm-svn: 215662
This change further evolves the base class AVX512_masking in order to make it
suitable for the masking variants of the FMA instructions.
Besides AVX512_masking there is now a new base class that instructions
including FMAs can use: AVX512_masking_3src. With three-source (destructive)
instructions one of the sources is already tied to the destination. This
difference from AVX512_masking is captured by this new class. The common bits
between _masking and _masking_3src are broken out into a new super class
called AVX512_masking_common.
As with valign, there is some corresponding restructuring of the underlying
format classes. The idea is the same we want to derive from two classes
essentially: one providing the format bits and another format-independent
multiclass supplying the various masking and non-masking instruction variants.
Existing fma tests in avx512-fma*.ll provide coverage here for the non-masking
variants. For masking, the next patches in the series will add intrinsics and
intrinsic tests.
For AVX512_masking_3src to work, the (ins ...) dag has to be passed *without*
the leading source operand that is tied to dst ($src1). This is necessary to
properly construct the (ins ...) for the different variants. For the record,
I did check that if $src is mistakenly included, you do get a fairly intuitive
error message from the tablegen backend.
Part of <rdar://problem/17688758>
llvm-svn: 215660
When preserving noalias function parameter attributes by adding noalias
metadata in the inliner, we should do this for general function calls (not just
memory intrinsics). The logic is very similar to what already existed (except
that we want to add this metadata even for functions taking no relevant
parameters). This metadata can be used by ModRef queries in the caller after
inlining.
This addresses the first part of PR20500. Adding noalias metadata during
inlining is still turned off by default.
llvm-svn: 215657
This patch allows a vector fneg of a bitcasted integer value to be optimized in the same way that we already optimize a scalar fneg. If the integer variable is a constant, we can precompute the result and not require any logic ops.
This patch is very similar to a fabs patch committed at r214892.
Differential Revision: http://reviews.llvm.org/D4852
llvm-svn: 215646
Summary:
This is done by removing some hardcoded registers like $at or expecting a single digit register to be selected.
Contains work done by Matheus Almeida.
Reviewers: matheusalmeida, dsanders
Reviewed By: dsanders
Subscribers: tomatabacu
Differential Revision: http://reviews.llvm.org/D4227
llvm-svn: 215640
lowering scheme.
Currently, this just directly bails to the fallback path of splitting
the 256-bit vector into two 128-bit vectors, operating there, and then
joining the results back together. While the results are far from
perfect, they are *shockingly* good for what we're doing here. I'll be
layering the rest of the functionality on top of this piece by piece and
updating tests as I go.
Note that 256-bit vectors in this mode are still somewhat WIP. While
I think the code paths that I'm adding here are clean and good-to-go,
there are still a lot of 128-bit assumptions that I'll need to stomp out
as I march through the functional spread here.
llvm-svn: 215637
Juergen Ributzka