This allows it to work properly with masked inc/dec for avx512. Those
would have a vselect as the root node so didn't get a chance to call
combineIncDecVector.
This also simplifies the logic because we don't have to manage
the topological ordering.
The flag isn't used, but I believe this matches the MOV32r0 that
would be created by the table emitter. This should allow this node
to be CSEed with any others created by the table.
A vselect+strictfp node is not equivalent to a masked operation.
The exceptions of the strictfp node are not masked by a vselect
after it so we can't match it to a masked operation.
We already had a hack in IsLegalToFold to prevent these patterns from
matching. This patch removes that hack and removes the patterns.
If we don't have cmov, X87 compares write to FPSW and we need to
move the bits to EFLAGS to use as JCC/SETCC/CMOV conditions.
Previously this was done by calling ConvertCmpIfNecessary in
multiple places which would emit the extra code for the FNSTSW,
a shift, a truncate, and a SAHF instructions. Isel would then
select trunc+X86ISD::CMP to a FUCOM instruction that produces FPSW.
This patch centralizes all of the handling into a single custom
isel handler. This allows us to remove ConvertCmpIfNecessary and
a couple target specific ISD opcodes.
Differential Revision: https://reviews.llvm.org/D73863
Only 32 and 64 bit SBB are dependency breaking instructons on some
CPUs. The 8 and 16 bit forms have to preserve upper bits of the GPR.
This patch removes the smaller forms and selects the wider form
instead. I had to do this with custom code as the tblgen generated
code glued the eflags copytoreg to the extract_subreg instead of
to the SETB pseudo.
Longer term I think we can remove X86ISD::SETCC_CARRY and use
(X86ISD::SBB zero, zero). We'll want to keep the pseudo and select
(X86ISD::SBB zero, zero) to either a MOV32r0+SBB for targets where
there is no dependency break and SETB_C32/SETB_C64 for targets
that have a dependency break. May want some way to avoid the MOV32r0
if the instruction that produced the carry flag happened to def a
register that we can use for the dependency.
I think the flag copy lowering should be using NEG instead of SUB to
handle SETB. That would avoid the MOV32r0 there. Or maybe it should
use a ADC with -1 to recreate the carry flag and keep the SETB?
That would avoid a MOVZX on the input of the SUB.
Differential Revision: https://reviews.llvm.org/D74024
This is an alternate fix for the issue D73606 was trying to
solve.
The main issue here is that we bailed out of
foldOffsetIntoAddress if Offset is 0. But if we just found a
symbolic displacement and AM.Disp became non-zero
earlier, we still need to validate that AM.Disp with the symbolic
displacement.
This is my second attempt at committing this after failing
build bots previously. One thing I realized about the previous
attempt is that its possible that AM.Disp is already non-zero
and the new Offset changes it back to zero. In that case my
previous attempt failed to update AM.Disp to zero. So this patch
removes the early out for 0 and appropriately handle the 0 case
in each check so we still update AM.Disp at the end.
This is an alternate fix for the issue D73606 was trying to
solve.
The main issue here is that we bailed out of
foldOffsetIntoAddress if Offset is 0. But if we just found a
symbolic displacement and AM.Disp became non-zero
earlier, we still need to validate that AM.Disp with the symbolic
displacement.
This passes fold-add-pcrel.ll.
Differential Revision: https://reviews.llvm.org/D73608
For `ret i64 add (i64 ptrtoint (i32* @foo to i64), i64 1701208431)`,
```
X86DAGToDAGISel::matchAdd
...
// AM.setBaseReg(CurDAG->getRegister(X86::RIP, MVT::i64));
if (!matchAddressRecursively(N.getOperand(0), AM, Depth+1) &&
// Try folding offset but fail; there is a symbolic displacement, so offset cannot be too large
!matchAddressRecursively(Handle.getValue().getOperand(1), AM, Depth+1))
return false;
...
// Try again after commuting the operands.
// AM.Disp = Val; foldOffsetIntoAddress() does not know there will be a symbolic displacement
if (!matchAddressRecursively(Handle.getValue().getOperand(1), AM, Depth+1) &&
// AM.setBaseReg(CurDAG->getRegister(X86::RIP, MVT::i64));
!matchAddressRecursively(Handle.getValue().getOperand(0), AM, Depth+1))
// Succeeded! Produced leaq sym+disp(%rip),...
return false;
```
`foldOffsetIntoAddress()` currently does not know there is a symbolic
displacement and can fold a large offset.
The produced `leaq sym+disp(%rip), %rax` instruction is relocated by
an R_X86_64_PC32. If disp is large and sym+disp-rip>=2**31, there
will be a relocation overflow.
This approach is still not elegant. Unfortunately the isRIPRelative
interface is a bit clumsy. I tried several solutions and eventually
picked this one.
Differential Revision: https://reviews.llvm.org/D73606
We use the stack for X87 fp_round and for moving from SSE f32/f64 to
X87 f64/f80. Or from X87 f64/f80 to SSE f32/f64.
Note for the SSE<->X87 conversions the conversion always happens in the
X87 domain. The load/store ops in the X87 instructions are able
to signal exceptions.
This allows us to delete InlineAsm::Constraint_i workarounds in
SelectionDAGISel::SelectInlineAsmMemoryOperand overrides and
TargetLowering::getInlineAsmMemConstraint overrides.
They were introduced to X86 in r237517 to prevent crashes for
constraints like "=*imr". They were later copied to other targets.
Fix several several additional problems with the int <-> FP conversion
logic both in common code and in the X86 target. In particular:
- The STRICT_FP_TO_UINT expansion emits a floating-point compare. This
compare can raise exceptions and therefore needs to be a strict compare.
I've made it signaling (even though quiet would also be correct) as
signaling is the more usual default for an LT. This code exists both
in common code and in the X86 target.
- The STRICT_UINT_TO_FP expansion algorithm was incorrect for strict mode:
it emitted two STRICT_SINT_TO_FP nodes and then used a select to choose one
of the results. This can cause spurious exceptions by the STRICT_SINT_TO_FP
that ends up not chosen. I've fixed the algorithm to use only a single
STRICT_SINT_TO_FP instead.
- The !isStrictFPEnabled logic in DoInstructionSelection would sometimes do
the wrong thing because it calls getOperationAction using the result VT.
But for some opcodes, incuding [SU]INT_TO_FP, getOperationAction needs to
be called using the operand VT.
- Remove some (obsolete) code in X86DAGToDAGISel::Select that would mutate
STRICT_FP_TO_[SU]INT to non-strict versions unnecessarily.
Reviewed by: craig.topper
Differential Revision: https://reviews.llvm.org/D71840
We really need to update the isel patterns to prevent this, but
that requires some tablegen de-tangling. So this hack will work
for correctness in the short term.
This has two main effects:
- Optimizes debug info size by saving 221.86 MB of obj file size in a
Windows optimized+debug build of 'all'. This is 3.03% of 7,332.7MB of
object file size.
- Incremental step towards decoupling target intrinsics.
The enums are still compact, so adding and removing a single
target-specific intrinsic will trigger a rebuild of all of LLVM.
Assigning distinct target id spaces is potential future work.
Part of PR34259
Reviewers: efriedma, echristo, MaskRay
Reviewed By: echristo, MaskRay
Differential Revision: https://reviews.llvm.org/D71320
Summary: This is a follow up of D69281, it enables the X86 backend support for the FP comparision.
Reviewers: uweigand, kpn, craig.topper, RKSimon, cameron.mcinally, andrew.w.kaylor
Subscribers: hiraditya, llvm-commits, annita.zhang, LuoYuanke, LiuChen3
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D70582
Summary:
This follows a previous patch that changes the X86 datalayout to represent
mixed size pointers (32-bit sext, 32-bit zext, and 64-bit) with address spaces
(https://reviews.llvm.org/D64931)
This patch implements the address space cast lowering to the corresponding
sign extension, zero extension, or truncate instructions.
Related to https://bugs.llvm.org/show_bug.cgi?id=42359
Reviewers: rnk, craig.topper, RKSimon
Subscribers: hiraditya, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D69639
This is the following patch of D68854.
This patch adds basic operations of X87 instructions, including +, -, *, / , fp extensions and fp truncations.
Patch by Chen Liu(LiuChen3)
Differential Revision: https://reviews.llvm.org/D68857
This allows operations that are marked Custom, but have some type
combinations that are legal to get past this code.
Add custom mutation code to X86's Select function for the nodes
that don't have isel patterns yet.
This seems to be causing some performance regresions that I'm
trying to investigate.
One thing that stands out is that this transform can increase
the live range of the operands of the earlier logic op. This
can be bad for register allocation. If there are two logic
op inputs we should really combine the one that is closest, but
SelectionDAG doesn't have a good way to do that. Maybe we need
to do this as a basic block transform in Machine IR.
llvm-svn: 373401
Summary:
This adds the ISD opcode and a DAG combine to create it. There are
probably some places where we can directly create it, but I'll
leave that for future work.
This updates all of the isel patterns to look for this new node.
I had to add a few additional isel patterns for aligned extloads
which we should probably fix with a DAG combine or something. This
does mean that the broadcast load folding for avx512 can no
longer match a broadcasted aligned extload.
There's still some work to do here for combining a broadcast of
a broadcast_load. We also need to improve extractelement or
demanded vector elements of a broadcast_load. I'll try to get
those done before I submit this patch.
Reviewers: RKSimon, spatel
Reviewed By: RKSimon
Subscribers: hiraditya, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D68198
llvm-svn: 373349
There's room from improvement here, but this is a decent
starting point.
There are a few minor regressions in the vector-rotate tests,
where we are now forming a vpternlog from an and before we get
a chance to form it for a bitselect that we were matching
previously. This results in an AND and an ANDN feeding the
vpternlog where previously we just had an AND after the
vpternlog. I think we can probably DAG combine the AND with
the bitselect to get back to similar codegen.
llvm-svn: 373172
This allows us to reduce the use count on the condition node before
the match. This enables load folding for that operand without
relying on the peephole pass. This will be improved on for
broadcast load folding in a subsequent commit.
This still requires a bunch of isel patterns for vXi16/vXi8 types
though.
llvm-svn: 373156
The attached test case would previous infinite loop after
r365711.
I'm going to move this to X86ISelDAGToDAG.cpp to get the setcc
to match VPTEST in 32-bit mode in a follow up commit.
llvm-svn: 372543
Summary:
PR43381 notes that while we are good at matching `(X >> C1) & C2` as BEXTR/BEXTRI,
we only do that if we either have BEXTRI (TBM),
or if BEXTR is marked as being fast (`-mattr=+fast-bextr`).
In all other cases we don't match.
But that is mainly only true for AMD CPU's.
However, for all the CPU's for which we have sched models,
the BZHI is always fast (or the sched models are all bad.)
So if we decide that it's unprofitable to emit BEXTR/BEXTRI,
we should consider falling-back to BZHI if it is available,
and follow-up with the shift.
While it's really tempting to do something because it's cool
it is wise to first think whether it actually makes sense to do.
We shouldn't just use BZHI because we can, but only it it is beneficial.
In particular, it isn't really worth it if the input is a register,
mask is small, or we can fold a load.
But it is worth it if the mask does not fit into 32-bits.
(careful, i don't know much about intel cpu's, my choice of `-mcpu` may be bad here)
Thus we manage to fold a load:
https://godbolt.org/z/Er0OQz
Or if we'd end up using BZHI anyways because the mask is large:
https://godbolt.org/z/dBJ_5h
But this isn'r actually profitable in general case,
e.g. here we'd increase microop count
(the register renaming is free, mca does not model that there it seems)
https://godbolt.org/z/k6wFoz
Likewise, not worth it if we just get load folding:
https://godbolt.org/z/1M1deGhttps://bugs.llvm.org/show_bug.cgi?id=43381
Reviewers: RKSimon, craig.topper, davezarzycki, spatel
Reviewed By: craig.topper, davezarzycki
Subscribers: andreadb, hiraditya, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D67875
llvm-svn: 372532
This reverts r372314, reapplying r372285 and the commits which depend
on it (r372286-r372293, and r372296-r372297)
This was missing one switch to getTargetConstant in an untested case.
llvm-svn: 372338
This broke the Chromium build, causing it to fail with e.g.
fatal error: error in backend: Cannot select: t362: v4i32 = X86ISD::VSHLI t392, Constant:i8<15>
See llvm-commits thread of r372285 for details.
This also reverts r372286, r372287, r372288, r372289, r372290, r372291,
r372292, r372293, r372296, and r372297, which seemed to depend on the
main commit.
> Encode them directly as an imm argument to G_INTRINSIC*.
>
> Since now intrinsics can now define what parameters are required to be
> immediates, avoid using registers for them. Intrinsics could
> potentially want a constant that isn't a legal register type. Also,
> since G_CONSTANT is subject to CSE and legalization, transforms could
> potentially obscure the value (and create extra work for the
> selector). The register bank of a G_CONSTANT is also meaningful, so
> this could throw off future folding and legalization logic for AMDGPU.
>
> This will be much more convenient to work with than needing to call
> getConstantVRegVal and checking if it may have failed for every
> constant intrinsic parameter. AMDGPU has quite a lot of intrinsics wth
> immarg operands, many of which need inspection during lowering. Having
> to find the value in a register is going to add a lot of boilerplate
> and waste compile time.
>
> SelectionDAG has always provided TargetConstant for constants which
> should not be legalized or materialized in a register. The distinction
> between Constant and TargetConstant was somewhat fuzzy, and there was
> no automatic way to force usage of TargetConstant for certain
> intrinsic parameters. They were both ultimately ConstantSDNode, and it
> was inconsistently used. It was quite easy to mis-select an
> instruction requiring an immediate. For SelectionDAG, start emitting
> TargetConstant for these arguments, and using timm to match them.
>
> Most of the work here is to cleanup target handling of constants. Some
> targets process intrinsics through intermediate custom nodes, which
> need to preserve TargetConstant usage to match the intrinsic
> expectation. Pattern inputs now need to distinguish whether a constant
> is merely compatible with an operand or whether it is mandatory.
>
> The GlobalISelEmitter needs to treat timm as a special case of a leaf
> node, simlar to MachineBasicBlock operands. This should also enable
> handling of patterns for some G_* instructions with immediates, like
> G_FENCE or G_EXTRACT.
>
> This does include a workaround for a crash in GlobalISelEmitter when
> ARM tries to uses "imm" in an output with a "timm" pattern source.
llvm-svn: 372314
Encode them directly as an imm argument to G_INTRINSIC*.
Since now intrinsics can now define what parameters are required to be
immediates, avoid using registers for them. Intrinsics could
potentially want a constant that isn't a legal register type. Also,
since G_CONSTANT is subject to CSE and legalization, transforms could
potentially obscure the value (and create extra work for the
selector). The register bank of a G_CONSTANT is also meaningful, so
this could throw off future folding and legalization logic for AMDGPU.
This will be much more convenient to work with than needing to call
getConstantVRegVal and checking if it may have failed for every
constant intrinsic parameter. AMDGPU has quite a lot of intrinsics wth
immarg operands, many of which need inspection during lowering. Having
to find the value in a register is going to add a lot of boilerplate
and waste compile time.
SelectionDAG has always provided TargetConstant for constants which
should not be legalized or materialized in a register. The distinction
between Constant and TargetConstant was somewhat fuzzy, and there was
no automatic way to force usage of TargetConstant for certain
intrinsic parameters. They were both ultimately ConstantSDNode, and it
was inconsistently used. It was quite easy to mis-select an
instruction requiring an immediate. For SelectionDAG, start emitting
TargetConstant for these arguments, and using timm to match them.
Most of the work here is to cleanup target handling of constants. Some
targets process intrinsics through intermediate custom nodes, which
need to preserve TargetConstant usage to match the intrinsic
expectation. Pattern inputs now need to distinguish whether a constant
is merely compatible with an operand or whether it is mandatory.
The GlobalISelEmitter needs to treat timm as a special case of a leaf
node, simlar to MachineBasicBlock operands. This should also enable
handling of patterns for some G_* instructions with immediates, like
G_FENCE or G_EXTRACT.
This does include a workaround for a crash in GlobalISelEmitter when
ARM tries to uses "imm" in an output with a "timm" pattern source.
llvm-svn: 372285
See D66309 for context.
This is the first sweep of x86 target specific code to add isAtomic bailouts where appropriate. The intention here is to have the switch from AtomicSDNode to LoadSDNode/StoreSDNode be close to NFC; that is, I'm not looking to allow additional optimizations at this time.
Sorry for the lack of tests. As discussed in the review, most of these are vector tests (for which atomicity is not well defined) and I couldn't figure out to exercise the anyextend cases which aren't vector specific.
Differential Revision: https://reviews.llvm.org/D66322
llvm-svn: 371547
As reported in post-commit review of r370327,
there is some case where the code crashes.
As discussed with Craig Topper, the problem is that getConstant()
internally calls getSplatBuildVector(), so we don't insert
the constant itself.
If we do that manually we're good.
llvm-svn: 371346
We can use a MOVSX16 here then rely on FixupBWInst to change to
MOVSX32 if the upper bits are dead. With a special case to
not promote if it could be turned into CBW.
Then we can rely on X86MCInstLower to turn the MOVSX into CBW
very late if register allocation worked out.
Using MOVSX gives an opportunity to use the MOVSX as a both a
copy and a sign extend since the input and output register aren't
tied together.
Differential Revision: https://reviews.llvm.org/D67192
llvm-svn: 371243
We can rely on X86FixupBWInsts to turn these into MOVZX32. This
simplifies a follow up commit to use MOVSX for i8 sdivrem with
a late optimization to use CBW when register allocation works out.
llvm-svn: 371242
Summary:
We were previously doing it in DAGCombine.
But we also want to do `sub %x, C` -> `add %x, (sub 0, C)` for vectors in DAGCombine.
So if we had `sub %x, -1`, we'll transform it to `add %x, 1`,
which `combineIncDecVector()` will immediately transform back into `sub %x, -1`,
and here we go again...
I've marked this as NFC since not a single test changes,
but since that 'changes' DAGCombine, probably this isn't fully NFC.
Reviewers: RKSimon, craig.topper, spatel
Reviewed By: craig.topper
Subscribers: hiraditya, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D62327
llvm-svn: 370327
LEA doesn't affect flags, so use it more liberally to replace an ADD when
we know that the ADD operands affect flags.
In the motivating example from PR40483:
https://bugs.llvm.org/show_bug.cgi?id=40483
...this lets us avoid duplicating a math op just to avoid flag conflict.
As mentioned in the TODO comments, this heuristic can be extended to
fire more often if that leads to more improvements.
Differential Revision: https://reviews.llvm.org/D64707
llvm-svn: 366431
Summary:
We attempt to prevent folding immediates with multiple users under optsize. But we only do this from store nodes and X86ISD::ADD/SUB/XOR/OR/AND patterns. We don't do it for ISD::ADD/SUB/XOR/OR/AND even though we count them as users when deciding whether to fold into other nodes. This leads to situations where we block folding to a compare for example, but still fold into an AND or OR as seen in PR27202.
Unfortunately touching the isel patterns in tablegen for the ISD::ADD/SUB/XOR/OR/AND opcodes will cause the patterns to be unusable for fast isel. And we don't have a way to make a fast isel only pattern.
To workaround this, this patch adds custom isel in front of the isel table that will select the non-immediate forms if the immediate has additional users. This may create some issues for ANDN and NOT matching. And there's room for improvement with unsigned 32 immediates on 64-bit AND.
This patch needs more thorough test cases, but I wanted to get feedback on the direction. Please send me any other test cases you've seen in the wild.
I think we probably have the same issue with the immediate matching when we fold RMW from X86ISD::ADD/SUB/XOR/OR/AND. And our TEST immedaite shrinking logic. Our cost modeling for immediates that can fit in a sign extended 8-bit immediate on a 16/32/64 bit operation is completely wrong.
I also wonder if we should update the ConstantHoisting cost model and block folding for "opaque" constants. But of course constants can still be created by DAG combine and lowering optimizations.
Fixes PR27202
Reviewers: spatel, RKSimon, andreadb
Reviewed By: RKSimon
Subscribers: jsji, hiraditya, jdoerfert, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D59909
llvm-svn: 365163
Summary:
The one thing of note here is that the 'bitwidth' constant (32/64) was previously pessimistic.
Given `x & (-1 >> (C - z))`, we were taking `C` to be `bitwidth(x)`, but in reality
we want `(-1 >> (C - z))` pattern to mean "low z bits must be all-ones".
And for that, `C` should be `bitwidth(-1 >> (C - z))`, i.e. of the shift operation itself.
Last pattern D does not seem to exhibit any of these truncation issues.
Although it has the opposite problem - if we extract low bits (no shift) from i64,
and then truncate to i32, then we fail to shrink this 64-bit extraction into 32-bit extraction.
Reviewers: RKSimon, craig.topper, spatel
Reviewed By: RKSimon
Subscribers: llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D62806
llvm-svn: 364419
Summary:
(Not so) boringly identical to pattern a (D62786)
Not yet sure how do deal with the last pattern c.
Reviewers: RKSimon, craig.topper, spatel
Reviewed By: RKSimon
Subscribers: llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D62793
llvm-svn: 364418
Summary:
Finally tying up loose ends here.
The problem is quite simple:
If we have pattern `(x >> start) & (1 << nbits) - 1`,
and then truncate the result, that truncation will be propagated upwards,
into the `and`. And that isn't currently handled.
I'm only fixing pattern `a` here,
the same fix will be needed for patterns `b`/`c` too.
I *think* this isn't missing any extra legality checks,
since we only look past truncations. Similary, i don't think
we can get any other truncation there other than i64->i32.
Reviewers: craig.topper, RKSimon, spatel
Reviewed By: craig.topper
Subscribers: llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D62786
llvm-svn: 364417
First step toward addressing the vector-reduce-mul-widen.ll regression in D63281 - we should replace ANY_EXTEND/ANY_EXTEND_VECTOR_INREG in X86ISelDAGToDAG to avoid having to add duplicate patterns when treating any extensions as legal.
In future patches this will also allow us to keep any extension nodes around a lot longer in the DAG, which should mean that we can keep better track of undef elements that otherwise become zeros that we think we have to keep......
Differential Revision: https://reviews.llvm.org/D63326
llvm-svn: 363655
I recently discovered a bug on the x86 platform: The fp80 type was not handled well by x86 for constrained floating point nodes, as their regular counterparts are replaced by extending loads and truncating stores during the preprocess phase. Normally, platforms don't have this issue, as they don't typically attempt to perform such legalizations during instruction selection preprocessing. Before this change, strict_fp nodes survived until they were mutated to normal nodes, which happened shortly after preprocessing on other platforms. This modification lowers these nodes at the same phase while properly utilizing the chain.5
Submitted by: Drew Wock <drew.wock@sas.com>
Reviewed by: Craig Topper, Kevin P. Neal
Approved by: Craig Topper
Differential Revision: https://reviews.llvm.org/D63271
llvm-svn: 363417
Previously we did the equivalent operation in isel patterns with
COPY_TO_REGCLASS operations to transition. By inserting
scalar_to_vetors and extract_vector_elts before isel we can
allow each piece to be selected individually and accomplish the
same final result.
I ideally we'd use vector operations earlier in lowering/combine,
but that looks to be more difficult.
The scalar-fp-to-i64.ll changes are because we have a pattern for
using movlpd for store+extract_vector_elt. While an f64 store
uses movsd. The encoding sizes are the same.
llvm-svn: 362914
We already need to have patterns for X86ISD::RNDSCALE to support software intrinsics. But we currently have 5 sets of patterns for the 5 rounding operations. For of these 6 patterns we have to support 3 vectors widths, 2 element sizes, sse/vex/evex encodings, load folding, and broadcast load folding. This results in a fair amount of bytes in the isel table.
This patch adds code to PreProcessIselDAG to morph the fceil/ffloor/ftrunc/fnearbyint/frint to X86ISD::RNDSCALE. This way we can remove everything, but the intrinsic pattern while still allowing the operations to be considered Legal for DAGCombine and Legalization. This shrinks the DAGISel by somewhere between 9K and 10K.
There is one complication to this, the STRICT versions of these nodes are currently mutated to their none strict equivalents at isel time when the node is visited. This won't be true in the future since that loses the chain ordering information. For now I've also added support for the non-STRICT nodes to Select so we can change the STRICT versions there after they've been mutated to their non-STRICT versions. We'll probably need a STRICT version of RNDSCALE or something to handle this in the future. Which will take us back to needing 2 sets of patterns for strict and non-strict, but that's still better than the 11 or 12 sets of patterns we'd need.
We can probably do something similar for scalar, but I haven't looked at it yet.
Differential Revision: https://reviews.llvm.org/D62757
llvm-svn: 362535
If we're trying to match an LEA, its possible the LEA match will be deemed unprofitable. In which case the negation we created in matchAddress would be left dangling in the SelectionDAG. This could artificially increase use counts for other nodes in the DAG. Though I don't have an example of that. But it just seems like bad form to have dangling nodes in isel.
Differential Revision: https://reviews.llvm.org/D61047
llvm-svn: 360823
The reordering can leave at least a dead TokenFactor in the graph. This cause the linearize scheduler to fail with something like the assert seen in PR22614. This is only one of many ways we can break the linearize scheduler today so I can't say for sure that any of the other failures in that bug were caused by this issue.
This takes the heavy hammer approach of just running RemoveDeadNodes unconditionally at the end of the PreprocessISelDAG. If this turns out to be a compile time hit, we can try to refine it.
Differential Revision: https://reviews.llvm.org/D61164
llvm-svn: 359582
The IndexReg will always be non-null at this point. Earlier in the function, if
IndexReg was null we set it to CurDAG->getRegister(0, VT) which made it
non-null.
llvm-svn: 359170
ReplaceAllUsesWith doesn't remove the node that was replaced. So its left around in the graph messing up use counts on other nodes.
One thing to note, is that this isn't valid if the node being deleted is the root node of an LEA match that gets rejected. In that case the node needs to stay alive because the isel table walking code would still have a reference to it that its going to try to match next. I don't think that's the case here though because the nodes being deleted here should be "and", "srl", and "zero_extend" none of which can be the root node of an LEA match.
Differential Revision: https://reviews.llvm.org/D61048
llvm-svn: 359121
The MOVZX doesn't require an immediate to be encoded at all. Though it does use
a 2 byte opcode so its the same size as a 1 byte immediate. But it has a
separate source and dest register so can help avoid copies.
llvm-svn: 358805
There's one slight regression in here because we don't check that the immediate
already allowed movzx before the shift. I'll fix that next.
llvm-svn: 358804
Summary:
There are two places where we create a HandleSDNode in address matching in order to handle the case where N is changed by CSE. But if we end up not matching, we fall back to code at the bottom of the switch that really would like N to point to something that wasn't CSEd away. So we should make sure we copy the handle back to N on any paths that can reach that code.
This appears to be the true reason we needed to check DELETED_NODE in the negation matching. In pr32329.ll we had two subtracts back to back. We recursed through the first subtract, and onto the second subtract. The second subtract called matchAddressRecursively on its LHS which caused that subtract to CSE. We ultimately failed the match and ended up in the default code. But N was pointing at the old node that had been deleted, but the default code didn't know that and took it as the base register. Then we unwound back to the first subtract and tried to access this bogus base reg requiring the check for deleted node. With this patch we now use the CSE result as the base reg instead.
matchAdd has been broken since sometime in 2015 when it was pulled out of the switch into a helper function. The assignment to N at the end was still there, but N was passed by value and not by reference so the update didn't go anywhere.
Reviewers: niravd, spatel, RKSimon, bkramer
Reviewed By: niravd
Subscribers: llvm-commits, hiraditya
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D60843
llvm-svn: 358735
The test file has pairs of tests that are logically equivalent:
https://rise4fun.com/Alive/2zQ
%t4 = and i8 %t1, 8
%t5 = zext i8 %t4 to i16
%sh = shl i16 %t5, 2
%t6 = add i16 %sh, %t0
=>
%t4 = and i8 %t1, 8
%sh2 = shl i8 %t4, 2
%z5 = zext i8 %sh2 to i16
%t6 = add i16 %z5, %t0
...so if we can fold the shift op into LEA in the 1st pattern, then we
should be able to do the same in the 2nd pattern (unnecessary 'movzbl'
is a separate bug I think).
We don't want to do this any sooner though because that would conflict
with generic transforms that try to narrow the width of the shift.
Differential Revision: https://reviews.llvm.org/D60789
llvm-svn: 358622
We had many tablegen patterns for these instructions. And due to the
commutability of the patterns, tablegen expands them to even more patterns. All
together VPTESTMD patterns accounted for more the 50K of the 610K isel table.
This had gotten bad when we stopped canonicalizing AND to vXi64. This required
a pattern for every combination of bitcast input type.
This change moves the matching to custom code where it is easier to look through
the bitcasts without being concerned with the specific types.
The test changes are because we are now stricter with one use checks as its
required to make load folding legal. We now require the AND and any BITCAST to
only have a single use. This prevents forming VPTESTM and a VPAND with the same
inputs.
We now support broadcast loads for 128/256 patterns without VLX. We'll widen to
512-bit like and still fold the broadcast since the amount of memory read
doesn't change.
There are a few tests that got slightly longer because are now prefering
load + VPTESTM over XOR+VPCMPEQ for (seteq (load), allzeros). Previously we were
able to share the XOR with multiple VPTESTM instructions.
llvm-svn: 358359
Summary:
The Linux kernel uses PC-relative mode, so allow that when the code model is
"kernel".
Reviewers: craig.topper
Reviewed By: craig.topper
Subscribers: llvm-commits, kees, nickdesaulniers
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D60643
llvm-svn: 358343
We know all our values are limited to 64 bits here so we don't need an APInt.
This should save some generated code checking between large and small size.
llvm-svn: 358338
foldMaskedShiftToScaledMask tries to reorder and & shl to enable the shl to fold into an LEA. But if there is an any_extend between them it doesn't work.
This patch modifies the code to look through any_extend from i32 to i64 when the and mask only uses bits that weren't from the extended part.
This will prevent a regression from D60358 caused by 64-bit SHL being narrowed to 32-bits when their upper bits aren't demanded.
Differential Revision: https://reviews.llvm.org/D60532
llvm-svn: 358139
These ifs were ensuring we don't have to handle types larger than 64 bits probably because we use getZExtValue in several places below them.
None of the callers of this code pass types larger than 64-bits so we can just assert instead of branching in release code.
I've also moved them earlier since we're just looking through operations that don't effect bit width.
This is prep work for some refactoring I plan to do to the (and (shl)) handling code.
llvm-svn: 358123
This function reorders AND and SHL to enable the SHL to fold into an LEA. The
upper bits of the AND will be shifted out by the SHL so it doesn't matter what
mask value we use for these bits. By using sign bits from the original mask in
these upper bits we might enable a shorter immediate encoding to be used.
llvm-svn: 357846
Summary:
This avoids needing an isel pattern for each condition code. And it removes translation switches for converting between Jcc instructions and condition codes.
Now the printer, encoder and disassembler take care of converting the immediate. We use InstAliases to handle the assembly matching. But we print using the asm string in the instruction definition. The instruction itself is marked IsCodeGenOnly=1 to hide it from the assembly parser.
Reviewers: spatel, lebedev.ri, courbet, gchatelet, RKSimon
Reviewed By: RKSimon
Subscribers: MatzeB, qcolombet, eraman, hiraditya, arphaman, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D60228
llvm-svn: 357802
Summary:
This avoids needing an isel pattern for each condition code. And it removes translation switches for converting between SETcc instructions and condition codes.
Now the printer, encoder and disassembler take care of converting the immediate. We use InstAliases to handle the assembly matching. But we print using the asm string in the instruction definition. The instruction itself is marked IsCodeGenOnly=1 to hide it from the assembly parser.
Reviewers: andreadb, courbet, RKSimon, spatel, lebedev.ri
Reviewed By: andreadb
Subscribers: hiraditya, lebedev.ri, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D60138
llvm-svn: 357801
Summary:
Reorder the condition code enum to match their encodings. Move it to MC layer so it can be used by the scheduler models.
This avoids needing an isel pattern for each condition code. And it removes
translation switches for converting between CMOV instructions and condition
codes.
Now the printer, encoder and disassembler take care of converting the immediate.
We use InstAliases to handle the assembly matching. But we print using the
asm string in the instruction definition. The instruction itself is marked
IsCodeGenOnly=1 to hide it from the assembly parser.
This does complicate the scheduler models a little since we can't assign the
A and BE instructions to a separate class now.
I plan to make similar changes for SETcc and Jcc.
Reviewers: RKSimon, spatel, lebedev.ri, andreadb, courbet
Reviewed By: RKSimon
Subscribers: gchatelet, hiraditya, kristina, lebedev.ri, jdoerfert, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D60041
llvm-svn: 357800
SUBREG_TO_REG is supposed to be used to assert that we know the upper bits are
zero. But that isn't the case here. We've done no analysis of the inputs.
llvm-svn: 357673
Craig Topper