We can do this optimization in the majority of cases, but we currently
don't have a way to do it. We do not track/model which instructions
have which behavior, the control bit to change the high bit behavior,
or making use of preserved bits at all. This is a bit fuzzy since we
don't know precisely how the source instruction will be lowered, but
that only really matters in one case (for fma_mixlo).
We do need to fixup some of these cases after selection, but the
pattern helps eliminate many of these zexts.
This allows to convert the add instruction to s_addk_i32 and
v_add_nc_u32 instead of needing v_add_co_u32 when converting to a VALU
instruction.
Differential Revision: https://reviews.llvm.org/D103322
When flat scratch is used, the stack pointer needs to be added when
writing arguments to the stack.
For buffer instructions, this is done in SelectMUBUFScratchOffen
and SelectMUBUFScratchOffset.
Move that to call argument lowering, like it is done in GlobalISel.
Differential Revision: https://reviews.llvm.org/D103166
gfx9 does not work with negative offsets, gfx10 works only with
aligned negative offsets, but not with unaligned negative offsets.
This is slightly more conservative than needed, gfx9 does support
negative offsets when a VGPR address is used and gfx10 supports
negative, unaligned offsets when an SGPR address is used, but we
do not make use of that with this patch.
Differential Revision: https://reviews.llvm.org/D101292
An address can be a uniform sum of two i64 bit values.
That regularly happens in a loop where index is an induction
variable promoted to 64 bit by the LSR. We can materialize
zero in a VGPR and still use SADDR form of the load.
Differential Revision: https://reviews.llvm.org/D101591
This is a service function generally useful for selection
of a FI in an SADDR. NFC for now, needed for future patch.
Differential Revision: https://reviews.llvm.org/D100406
Use SIInstrFlags to differentiate between the different
variants of flat instructions (flat, global and scratch).
This should make it easier to bundle the immediate offset logic in a
single place and implement restrictions and bug workarounds.
Fixed version of D99587, which does not rely on the address space.
Differential Revision: https://reviews.llvm.org/D99743
Replace individual operands GLC, SLC, and DLC with a single cache_policy
bitmask operand. This will reduce the number of operands in MIR and I hope
the amount of code. These operands are mostly 0 anyway.
Additional advantage that parser will accept these flags in any order unlike
now.
Differential Revision: https://reviews.llvm.org/D96469
* Add amdgcn_strict_wqm intrinsic.
* Add a corresponding STRICT_WQM machine instruction.
* The semantic is similar to amdgcn_strict_wwm with a notable difference that not all threads will be forcibly enabled during the computations of the intrinsic's argument, but only all threads in quads that have at least one thread active.
* The difference between amdgc_wqm and amdgcn_strict_wqm, is that in the strict mode an inactive lane will always be enabled irrespective of control flow decisions.
Reviewed By: critson
Differential Revision: https://reviews.llvm.org/D96258
* Introduce the new intrinsic amdgcn_strict_wwm
* Deprecate the old intrinsic amdgcn_wwm
The change is done for consistency as the "strict"
prefix will become an important, distinguishing factor
between amdgcn_wqm and amdgcn_strictwqm in the future.
The "strict" prefix indicates that inactive lanes do not
take part in control flow, specifically an inactive lane
enabled by a strict mode will always be enabled irrespective
of control flow decisions.
The amdgcn_wwm will be removed, but doing so in two steps
gives users time to switch to the new name at their own pace.
Reviewed By: critson
Differential Revision: https://reviews.llvm.org/D96257
During instruction selection, there is an inconsistency in choosing
the initial soffset value. With certain early passes, this value is
getting modified and that brought additional fixup during
eliminateFrameIndex to work for all cases. This whole transformation
looks trivial and can be handled better.
This patch clearly defines the initial value for soffset and keeps it
unchanged before eliminateFrameIndex. The initial value must be zero
for MUBUF with a frame index. The non-frame index MUBUF forms that
use a raw offset from SP will have the stack register for soffset.
During frame elimination, the soffset remains zero for entry functions
with zero dynamic allocas and no callsites, or else is updated to the
appropriate frame/stack register.
Also, did some code clean up and made all asserts around soffset
stricter to match.
Reviewed By: scott.linder
Differential Revision: https://reviews.llvm.org/D95071
Previously, instructions which could be
expressed as VOP3 in addition to another
encoding had a _e64 suffix on the tablegen
record name, while those
only available as VOP3 did not. With this
patch, all VOP3s will have the _e64 suffix.
The assembly does not change, only the mir.
Reviewed By: foad
Differential Revision: https://reviews.llvm.org/D94341
Change-Id: Ia8ec8890d47f8f94bbbdac43745b4e9dd2b03423
This change adds a real glc operand to the return atomic
instead of just string " glc" in the middle of the asm
string.
Improves asm parser diagnostics.
Differential Revision: https://reviews.llvm.org/D90730
These instructions use a scaled offset. We were wrongly selecting them
even when the required offset was not a multiple of the scale factor.
Differential Revision: https://reviews.llvm.org/D90607
V_DIV_SCALE_F32/F64 are VOP3B encoded so they can't use the ABS src
modifier, but they can still use NEG and the usual output modifiers.
This partially reverts 3b99f12a4e "AMDGPU: Remove modifiers from v_div_scale_*".
Differential Revision: https://reviews.llvm.org/D90296
The support is disabled by default. So far there is instruction
selection, spilling, and frame elimination. It also changes SP
from unswizzled to swizzled as used by flat scratch instructions,
so it cannot be mixed with MUBUF stack access.
At the very least missing:
- GlobalISel;
- Some optimizations in frame elimination in between vector
and scalar ALU;
- It shall finally allow to always materialize frame index
as an SGPR, but that is not implemented and frame elimination
cannot handle it yet;
- Unaligned and/or multidword flat scratch shall work, but it
is legalized now for MUBUF;
- Operand folding cannot optimize FI like with MUBUF yet;
- It will need scaling the value of the SP/FP in the DWARF
expression to recover the unswizzled scratch address;
Differential Revision: https://reviews.llvm.org/D89170
We use an absolute address for stack objects and
it would be necessary to have a constant 0 for soffset field.
Fixes: SWDEV-228562
Reviewed By: arsenm
Differential Revision: https://reviews.llvm.org/D89234
Previously SDNodeFlags::instersectWith(Flags) would do nothing if Flags was
in an undefined state, which is very bad given that this is the default when
getNode() is called without passing an explicit SDNodeFlags argument.
This meant that if an already existing and reused node had a flag which the
second caller to getNode() did not set, that flag would remain uncleared.
This was exposed by https://bugs.llvm.org/show_bug.cgi?id=47092, where an NSW
flag was incorrectly set on an add instruction (which did in fact overflow in
one of the two original contexts), so when SystemZElimCompare removed the
compare with 0 trusting that flag, wrong-code resulted.
There is more that needs to be done in this area as discussed here:
Differential Revision: https://reviews.llvm.org/D86871
Review: Ulrich Weigand, Sanjay Patel
This would assert with unaligned DS access enabled. The offset may not
be aligned. Theoretically the pattern predicate should check the
memory alignment, although it is possible to have the memory be
aligned but not the immediate offset.
In this case I would expect it to use ds_{read|write}_b64 with
unaligned access, but am not clear if there's a reason it doesn't.
Fix local ds_read/write_b96/b128 so they can be selected if the alignment
allows. Otherwise, either pick appropriate ds_read2/write2 instructions or break
them down.
Differential Revision: https://reviews.llvm.org/D81638
The previous implementation was incorrect, and based off incorrect
instruction definitions. Unfortunately we can't match natural
addressing in a lot of cases due to the shift/scale applied in
getelementptrs. This relies on reducing the 64-bit shift to 32-bits.
This was always set to 0. Use a default value of 0 in this context to
satisfy the instruction definition patterns. We can't unconditionally
use SLC with a default value of 0 due to limitations in TableGen's
handling of defaulted operands when followed by non-default operands.
As explained in the comment:
// For a FLAT instruction the hardware decides whether to access
// global/scratch/shared memory based on the high bits of vaddr,
// ignoring the offset field, so we have to ensure that when we add
// remainder to vaddr it still points into the same underlying object.
// The easiest way to do that is to make sure that we split the offset
// into two pieces that are both >= 0 or both <= 0.
In particular FLAT (as opposed to SCRATCH and GLOBAL) instructions have
an unsigned immediate offset field, so we can't use it to help split a
negative offset.
Differential Revision: https://reviews.llvm.org/D83394
The hardware has created a real mess in the naming for add/sub, which
have been renamed basically every generation. Switch the carry out
pseudos to have the gfx9/gfx10 names. We were using the original SI/CI
v_add_i32/v_sub_i32 names. Later targets reintroduced these names as
carryless instructions with a saturating clamp bit, which we do not
define. Do this rename so we can unambiguously add these missing
instructions.
The carry-in versions should also be renamed, but at least those had a
consistent _u32 name to begin with. The 16-bit instructions were also
renamed, but aren't ambiguous.
This does regress assembler error message quality in some cases. In
mismatched wave32/wave64 situations, this will switch from
"unsupported instruction" to "invalid operand", with the error
pointing at the wrong position. I couldn't quite follow how the
assembler selects these, but the previous behavior seemed accidental
to me. It looked like there was a partial attempt to handle this which
was never completed (i.e. there is an AMDGPUOperand::isBoolReg but it
isn't used for anything).
Summary:
- AssertAlign node records the guaranteed alignment on its source node,
where these alignments are retrieved from alignment attributes in LLVM
IR. These tracked alignments could help DAG combining and lowering
generating efficient code.
- In this patch, the basic support of AssertAlign node is added. So far,
we only generate AssertAlign nodes on return values from intrinsic
calls.
- Addressing selection in AMDGPU is revised accordingly to capture the
new (base + offset) patterns.
Reviewers: arsenm, bogner
Subscribers: jvesely, wdng, nhaehnle, tpr, hiraditya, kerbowa, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D81711
I'm guessing this was a holdover from when 0 was an invalid stack
pointer, but surprised nobody has discovered this before.
Also don't allow offset folding for -1 pointers, since it looks weird
to partially fold this.
SelectMOVRELOffset prevents peeling of a constant from an index
if final base could be negative. isBaseWithConstantOffset() succeeds
if a value is an "add" or "or" operator. In case of "or" it shall
be an add-like "or" which never changes a sign of the sum given a
non-negative offset. I.e. we can safely allow peeling if operator is
an "or".
Differential Revision: https://reviews.llvm.org/D79898
Summary: This change enables all kind of carry out ISD opcodes to be selected according to the node divergence.
Reviewers: rampitec, arsenm, vpykhtin
Reviewed By: rampitec
Subscribers: kzhuravl, jvesely, wdng, nhaehnle, yaxunl, dstuttard, tpr, t-tye, hiraditya, kerbowa, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D78091
This was yet another function that had to be updated whenever you added
a new register class. Remove it by refactoring its only caller to use
standard helper functions from SIRegisterInfo.
Differential Revision: https://reviews.llvm.org/D78557
Matt Arsenault