Commit Graph

1125 Commits

Author SHA1 Message Date
Nikita Popov 1ffa6499ea [TargetLowering] Use IRBuilderBase instead of IRBuilder<> (NFC)
Don't require a specific kind of IRBuilder for TargetLowering hooks.
This allows us to drop the IRBuilder.h include from TargetLowering.h.

Differential Revision: https://reviews.llvm.org/D103759
2021-06-06 16:29:50 +02:00
Florian Hahn c2d44bd230
[X86] Lower calls with clang.arc.attachedcall bundle
This patch adds support for lowering function calls with the
`clang.arc.attachedcall` bundle. The goal is to expand such calls to the
following sequence of instructions:

    callq   @fn
    movq  %rax, %rdi
    callq   _objc_retainAutoreleasedReturnValue / _objc_unsafeClaimAutoreleasedReturnValue

This sequence of instructions triggers Objective-C runtime optimizations,
hence we want to ensure no instructions get moved in between them.
This patch achieves that by adding a new CALL_RVMARKER ISD node,
which gets turned into the CALL64_RVMARKER pseudo, which eventually gets
expanded into the sequence mentioned above.

The ObjC runtime function to call is determined by the
argument in the bundle, which is passed through as a
target constant to the pseudo.

@ahatanak is working on using this attribute in the front- & middle-end.

Together with the front- & middle-end changes, this should address
PR31925 for X86.

This is the X86 version of 46bc40e502,
which added similar support for AArch64.

Reviewed By: ab

Differential Revision: https://reviews.llvm.org/D94597
2021-05-21 16:33:58 +01:00
Serge Pavlov 12537ab772 [FPEnv][X86] Implement lowering of llvm.set.rounding
Differential Revision: https://reviews.llvm.org/D74730
2021-05-13 14:30:38 +07:00
Sander de Smalen 43ace8b5ce [TTI] NFC: Change getScalingFactorCost to return InstructionCost
This patch migrates the TTI cost interfaces to return an InstructionCost.

See this patch for the introduction of the type: https://reviews.llvm.org/D91174
See this thread for context: http://lists.llvm.org/pipermail/llvm-dev/2020-November/146408.html

Differential Revision: https://reviews.llvm.org/D100564
2021-04-23 16:06:36 +01:00
Nick Desaulniers c440b97d89 [TargetLowering] move "o" and "X" constraint handling to base class
These constraints are machine agnostic; there's no reason to handle
these per-arch. If arches don't support these constraints, then they
will fail elsewhere during instruction selection. We don't need virtual
calls to look these up; TargetLowering::getInlineAsmMemConstraint should
only be overridden by architectures with additional unique memory
constraints.

Reviewed By: echristo, MaskRay

Differential Revision: https://reviews.llvm.org/D100416
2021-04-19 10:53:31 -07:00
Alexey Lapshin cf7cdaff64 [X86][VARARG] Avoid spilling xmm registers for va_start.
That review is extracted from D69372.
It fixes https://bugs.llvm.org/show_bug.cgi?id=42219 bug.

For the noimplicitfloat mode, the compiler mustn't generate
floating-point code if it was not asked directly to do so.
This rule does not work with variable function arguments currently.
Though compiler correctly guards block of code, which copies xmm vararg
parameters with a check for %al, it does not protect spills for xmm registers.
Thus, such spills are generated in non-protected areas and could break code,
which does not expect floating-point data. The problem happens in -O0
optimization mode. With this optimization level there is used
FastRegisterAllocator, which spills virtual registers at basic block boundaries.
Register Allocator does not protect spills with additional control-flow modifications.
Thus to resolve that problem, it is suggested to not copy incoming physical
registers into virtual registers. Instead, store incoming physical xmm registers
into the memory from scratch.

Differential Revision: https://reviews.llvm.org/D80163
2021-03-06 15:25:47 +03:00
Craig Topper 11ef356d9e [TargetLowering] Use Align in allowsMisalignedMemoryAccesses.
Reviewed By: arsenm

Differential Revision: https://reviews.llvm.org/D96097
2021-02-04 19:22:06 -08:00
Max Kazantsev d6bb96e677 [X86] Add experimental option to separately tune alignment of innermost loops
We already have an experimental option to tune loop alignment. Its impact
is very wide (and there is a suspicion that it's not always profitable). We want
to have something more narrow to play with. This patch adds similar option that
overrides preferred alignment for innermost loops. This is for experimental
purposes, default values do not change the existing behavior.

Differential Revision: https://reviews.llvm.org/D94895
Reviewed By: pengfei
2021-01-21 11:15:16 +07:00
Bevin Hansson 07605ea1f3 [X86] Improved lowering for saturating float to int.
Adapted from D54696 by @nikic.

This patch improves lowering of saturating float to
int conversions, FP_TO_[SU]INT_SAT, for X86.

Reviewed By: craig.topper

Differential Revision: https://reviews.llvm.org/D86079
2021-01-12 15:44:41 +01:00
Fangrui Song 6be0b9a8dd [X86] Don't fold negative offset into 32-bit absolute address (e.g. movl $foo-1, %eax)
When building abseil-cpp `bin/absl_hash_test` with Clang in -fno-pic
mode, an instruction like `movl $foo-2147483648, $eax` may be produced
(subtracting a number from the address of a static variable). If foo's
address is smaller than 2147483648, GNU ld/gold/LLD will error because
R_X86_64_32 cannot represent a negative value.

```
using absl::Hash;
struct NoOp {
  template < typename HashCode >
  friend HashCode AbslHashValue(HashCode , NoOp );
};
template <typename> class HashIntTest : public testing::Test {};
TYPED_TEST_SUITE_P(HashIntTest);
TYPED_TEST_P(HashIntTest, BasicUsage) {
  if (std::numeric_limits< TypeParam >::min )
    EXPECT_NE(Hash< NoOp >()({}),
              Hash< TypeParam >()(std::numeric_limits< TypeParam >::min()));
}
REGISTER_TYPED_TEST_CASE_P(HashIntTest, BasicUsage);
using IntTypes = testing::Types< int32_t>;
INSTANTIATE_TYPED_TEST_CASE_P(My, HashIntTest, IntTypes);

ld: error: hash_test.cc:(function (anonymous namespace)::gtest_suite_HashIntTest_::BasicUsage<int>::TestBody(): .text+0x4E472): relocation R_X86_64_32 out of range: 18446744071564237392 is not in [0, 4294967295]; references absl::hash_internal::HashState::kSeed
```

Actually any negative offset is not allowed because the symbol address
can be zero (e.g. set by `-Wl,--defsym=foo=0`). So disallow such folding.

Reviewed By: pengfei

Differential Revision: https://reviews.llvm.org/D93931
2020-12-30 18:47:26 -08:00
Simon Pilgrim 8767f3bb97 [X86][AVX] Remove X86ISD::SUBV_BROADCAST (PR38969)
Followup to D92645 - remove the remaining places where we create X86ISD::SUBV_BROADCAST, and fold splatted vector loads to X86ISD::SUBV_BROADCAST_LOAD instead.

Remove all the X86SubVBroadcast isel patterns, including all the fallbacks for if memory folding failed.
2020-12-18 15:49:53 +00:00
Simon Pilgrim cdb692ee0c [X86] Add X86ISD::SUBV_BROADCAST_LOAD and begin removing X86ISD::SUBV_BROADCAST (PR38969)
Subvector broadcasts are only load instructions, yet X86ISD::SUBV_BROADCAST treats them more generally, requiring a lot of fallback tablegen patterns.

This initial patch replaces constant vector lowering inside lowerBuildVectorAsBroadcast with direct X86ISD::SUBV_BROADCAST_LOAD loads which helps us merge a number of equivalent loads/broadcasts.

As well as general plumbing/analysis additions for SUBV_BROADCAST_LOAD, I needed to wrap SelectionDAG::makeEquivalentMemoryOrdering so it can handle result chains from non generic LoadSDNode nodes.

Later patches will continue to replace X86ISD::SUBV_BROADCAST usage.

Differential Revision: https://reviews.llvm.org/D92645
2020-12-17 10:25:25 +00:00
QingShan Zhang ebdd20f430 Expand the fp_to_int/int_to_fp/fp_round/fp_extend as libcall for fp128
X86 and AArch64 expand it as libcall inside the target. And PowerPC also
want to expand them as libcall for P8. So, propose an implement in the
legalizer to common the logic and remove the code for X86/AArch64 to
avoid the duplicate code.

Reviewed By: Craig Topper

Differential Revision: https://reviews.llvm.org/D91331
2020-12-17 07:59:30 +00:00
Harald van Dijk 9eac818370
[X86] Fix variadic argument handling for x32
The X86-64 ABI defines va_list as

  typedef struct {
    unsigned int gp_offset;
    unsigned int fp_offset;
    void *overflow_arg_area;
    void *reg_save_area;
  } va_list[1];

This means the size, alignment, and reg_save_area offset will depend on
whether we are in LP64 or in ILP32 mode, so this commit adds the checks.
Additionally, the VAARG_64 pseudo-instruction assumed 64-bit pointers, so
this commit adds a VAARG_X32 pseudo-instruction that behaves just like
VAARG_64, except for assuming 32-bit pointers.

Some of these changes were originally done by
Michael Liao <michael.hliao@gmail.com>.

Fixes https://bugs.llvm.org/show_bug.cgi?id=48428.

Reviewed By: RKSimon

Differential Revision: https://reviews.llvm.org/D93160
2020-12-14 23:47:27 +00:00
Simon Pilgrim 47321c311b [X86][SSE] combineReductionToHorizontal - add vXi8 ISD::MUL reduction handling (PR39709)
Default expansion leads to repeated extensions/truncations to/from vXi16 which shuffle combining and demanded elts can't completely unravel.

Better just to promote (any_extend) the input and perform a vXi16 reduction.

We'll be able to remove a lot of this if we ever get decent legalization support for reduction intrinsics in SelectionDAG.
2020-12-13 15:22:54 +00:00
Craig Topper a7eae62a42 [SelectionDAG][X86][PowerPC][Mips] Replace the default implementation of LowerOperationWrapper with the X86 and PowerPC version.
The default version only works if the returned node has a single
result. The X86 and PowerPC versions support multiple results
and allow a single result to be returned from a node with
multiple outputs. And allow a single result that is not result 0
of the node.

Also replace the Mips version since the new version should work
for it. The original version handled multiple results, but only
if the new node and original node had the same number of results.

Differential Revision: https://reviews.llvm.org/D91846
2020-11-20 10:06:53 -08:00
Tianqing Wang be39a6fe6f [X86] Add User Interrupts(UINTR) instructions
For more details about these instructions, please refer to the latest
ISE document:
https://software.intel.com/en-us/download/intel-architecture-instruction-set-extensions-programming-reference.

Reviewed By: craig.topper

Differential Revision: https://reviews.llvm.org/D89301
2020-10-22 17:33:07 +08:00
Craig Topper 375849518d [X86] Add a X86ISD::BEXTRI to distinquish the case where the control must be a constant.
The bextri intrinsic has a ImmArg attribute which will be converted
in SelectionDAG using TargetConstant. We previously converted this
to a plain Constant to allow X86ISD::BEXTR to call SimplifyDemandedBits
on it.

But while trying to decide if D89178 was safe, I realized that
this conversion of TargetConstant to Constant would be one case
where that would break.

So this patch adds a new opcode specifically for the immediate case.
And then teaches computeKnownBits and SimplifyDemandedBits to also
handle it, but not try to SimplifyDemandedBits on it. To make up
for that, I immediately masked the constant to 16 bits when
converting from the intrinsic node to the X86ISD node.
2020-10-10 19:18:06 -07:00
Craig Topper 68e1a8d207 [X86] Defer the creation of LCMPXCHG16B_SAVE_RBX until finalize-isel
We need to use LCMPXCHG16B_SAVE_RBX if RBX/EBX is being used as
the frame pointer. We previously checked for this during type
legalization, but that's too early to know for sure if the base
pointer is needed.

This patch adds a new pseudo instruction to emit from isel that
uses a virtual register for the RBX input. Then we use the custom
inserter hook to emit LCMPXCHG16B if RBX isn't needed as a base
pointer or LCMPXCHG16B_SAVE_RBX if it is.

Fixes PR42064.

Reviewed By: pengfei

Differential Revision: https://reviews.llvm.org/D88808
2020-10-07 17:00:43 -07:00
Craig Topper a7e45ea30d [X86] Add memory operand to AESENC/AESDEC Key Locker instructions.
This removes FIXMEs from selectAddr.
2020-10-03 21:42:16 -07:00
Craig Topper 7f3da48885 [X86] Remove X86ISD::MWAITX_DAG. Just match the intrinsic to the custom inserter pseudo instruction during isel. 2020-10-03 18:44:53 -07:00
Craig Topper adccc0bfa3 [X86] Add X86ISD opcodes for the Key Locker AESENC*KL and AESDEC*KL instructions
Instead of emitting MachineSDNodes during lowering, emit X86ISD
opcodes. These opcodes will either be selected by tablegen
patterns or custom selection code.

Emitting MachineSDNodes during lowering is uncommon so this makes
things more consistent. It also allows selectAddr to be called to
perform address matching during instruction selection.

I had trouble getting tablegen to accept XMM0-XMM7 as results in
an isel pattern for the WIDE instructions so I had to use custom
instruction selection.
2020-10-03 16:55:19 -07:00
Craig Topper 8ae4842669 [X86] Move MWAITX_DAG ISD opcode so it is not in the strict FP range.
Add a comment to hopefully prevent anyone else from making the
same mistake.
2020-10-02 18:22:02 -07:00
Pierre Gousseau cda6b09242 [X86] Make sure we do not clobber RBX with mwaitx when used as a base
pointer.

mwaitx uses EBX as one of its argument.
Using this instruction clobbers RBX as it is defined to hold one of the
input. When the backend uses dynamically allocated stack, RBX is used as
a reserved register for the base pointer.

This patch is adapted from @qcolombet patch for cmpxchg at r263325.

This fixes PR43528.

Reviewed By: craig.topper

Differential Revision: https://reviews.llvm.org/D73475
2020-08-26 11:20:31 +01:00
Wang, Pengfei 9512525947 [X86][FPEnv] Teach X86 mask compare intrinsics to respect strict FP semantics.
When we use mask compare intrinsics under strict FP option, the masked
elements shouldn't raise any exception. So, we cann't replace the
intrinsic with a full compare + "and" operation.

Reviewed By: craig.topper

Differential Revision: https://reviews.llvm.org/D85385
2020-08-11 10:28:41 +08:00
Simon Pilgrim d14a22da5e [DAG] TargetLowering::LowerAsmOutputForConstraint - pass SDLoc as const&
Try to be more consistent with the SDLoc param in the TargetLowering methods.
2020-08-02 15:12:02 +01:00
Matt Arsenault 57bd64ff84 Support addrspacecast initializers with isNoopAddrSpaceCast
Moves isNoopAddrSpaceCast to the TargetMachine. It logically belongs
with the DataLayout.
2020-07-31 10:42:43 -04:00
Liu, Chen3 ea85ff82c8 [X86] Fix a bug that when lowering byval argument
When an argument has 'byval' attribute and should be
passed on the stack according calling convention,
a stack copy would be emitted twice. This will cause
the real value will be put into stack where the pointer
should be passed.

Differential Revision: https://reviews.llvm.org/D83175
2020-07-07 21:49:31 +08:00
Simon Pilgrim 973685fc78 [TargetLowering] Add DemandedElts arg to ShrinkDemandedConstant
Pre-commit for D82257, this adds a DemandedElts arg to ShrinkDemandedConstant/targetShrinkDemandedConstant which will allow future patches to (optionally) add vector support.
2020-06-29 11:46:58 +01:00
David Green 730ecb63ec [CGP] Convert phi types
If a collection of interconnected phi nodes is only ever loaded, stored
or bitcast then we can convert the whole set to the bitcast type,
potentially helping to reduce the number of register moves needed as the
phi's are passed across basic block boundaries. This has to be done in
CodegenPrepare as it naturally straddles basic blocks.

The alorithm just looks from phi nodes, looking at uses and operands for
a collection of nodes that all together are bitcast between float and
integer types. We record visited phi nodes to not have to process them
more than once. The whole subgraph is then replaced with a new type.
Loads and Stores are bitcast to the correct type, which should then be
folded into the load/store, changing it's type.

This comes up in the biquad testcase due to the way MVE needs to keep
values in integer registers. I have also seen it come up from aarch64
partner example code, where a complicated set of sroa/inlining produced
integer phis, where float would have been a better choice.

I also added undef and extract element handling which increased the
potency in some cases.

This adds it with an option that defaults to off, and disabled for 32bit
X86 due to potential issues around canonicalizing NaNs.

Differential Revision: https://reviews.llvm.org/D81827
2020-06-21 15:54:17 +01:00
Simon Pilgrim fb9f9dc318 [X86][SSE] Add SimplifyDemandedVectorEltsForTargetShuffle to handle target shuffle variable masks
Pulled out from the ongoing work on D66004, currently we don't do a good job of simplifying variable shuffle masks that have already lowered to constant pool entries.

This patch adds SimplifyDemandedVectorEltsForTargetShuffle (a custom x86 helper) to first try SimplifyDemandedVectorElts (which we already do) and then constant pool simplification to help mark undefined elements.

To prevent lowering/combines infinite loops, we only handle basic constant pool loads instead of creating new BUILD_VECTOR nodes for lowering - e.g. we don't try to convert them to broadcast/vzext_load - there might be some benefit to this but if so I'd rather we come up with some way to reuse existing code than reimplement a lot of BUILD_VECTOR code.

Differential Revision: https://reviews.llvm.org/D81791
2020-06-21 11:16:07 +01:00
QingShan Zhang 2b59e9f1bd [DAGCombine] Remove the getNegatibleCost to avoid the out of sync with getNegatedExpression
We have the getNegatibleCost/getNegatedExpression to evaluate the cost and negate the expression.
However, during negating the expression, the cost might change as we are changing the DAG,
and then, hit the assertion if we negated the wrong expression as the cost is not trustful anymore.

This patch is target to remove the getNegatibleCost to avoid the out of sync with getNegatedExpression,
and check the cost during negating the expression. It also reduce the duplicated code between
getNegatibleCost and getNegatedExpression. And fix the crash for the test in D76638

Reviewed By: RKSimon, spatel

Differential Revision: https://reviews.llvm.org/D77319
2020-05-20 02:12:16 +00:00
Alexey Lapshin da30c3796a [x86][NFC] Apply clang-format to X86ISelLowering.h
Summary:
  Apply clang-format to X86ISelLowering.h

Reviewed by: aeubanks

Differential Revision: https://reviews.llvm.org/D80005
2020-05-15 19:48:16 +03:00
Sanjay Patel f490ca76b0 [x86][CGP] enable target hook to sink funnel shift intrinsic's splatted shift amount
SDAG suffers when it can't see that a funnel operand is a splat value
(due to single-basic-block visibility), so invert the normal loop
hoisting rules to move a splat op closer to its use.

This would be part 1 of an enhancement similar to D63233.

This is needed to re-fix PR37426:
https://bugs.llvm.org/show_bug.cgi?id=37426
...because we got better at canonicalizing IR to funnel shift intrinsics.

The existing CGP code for shift opcodes is likely overstepping what it was
intended to do, so that will be fixed in a follow-up.

Differential Revision: https://reviews.llvm.org/D79718
2020-05-12 18:40:40 -04:00
Sam McCall 728cf6d86b Revert "[DAGCombine] Remove the getNegatibleCost to avoid the out of sync with getNegatedExpression"
This reverts commit 3c44c441db.

Causes infloops on some inputs, see https://reviews.llvm.org/D77319 for repro
2020-05-11 16:44:01 +02:00
QingShan Zhang 3c44c441db [DAGCombine] Remove the getNegatibleCost to avoid the out of sync with getNegatedExpression
We have the getNegatibleCost/getNegatedExpression to evaluate the cost and negate the expression.
However, during negating the expression, the cost might change as we are changing the DAG,
and then, hit the assertion if we negated the wrong expression as the cost is not trustful anymore.

This patch is target to remove the getNegatibleCost to avoid the out of sync with getNegatedExpression,
and check the cost during negating the expression. It also reduce the duplicated code between
getNegatibleCost and getNegatedExpression. And fix the crash for the test in D76638

Reviewed By: RKSimon, spatel

Differential Revision: https://reviews.llvm.org/D77319
2020-05-11 02:41:10 +00:00
QingShan Zhang 2957fa0cd1 [NFC][DAGCombine] Adding three helper functions and change the getNegatedExpression to negateExpression
This is a NFC patch for D77319. The idea is to hide the getNegatibleCost inside the getNegatedExpression()
to have it return null if the cost is expensive, and add some helper function for easy to use. And
rename the old getNegatedExpression to negateExpression to avoid the semantic conflict.

Reviewed By: RKSimon

Differential revision: https://reviews.llvm.org/D78291
2020-04-27 04:11:42 +00:00
Simon Pilgrim 4425751317 X86ISelLowering.h - remove unnecessary includes. NFC.
Fixed implicit MachineFrameInfo.h dependency in X86SelectionDAGInfo.cpp
2020-04-25 20:07:34 +01:00
Craig Topper d7e2d937bc [X86] Add X86ISD nodes for PDEP and PEXT.
This will allow use to add DAG combines for these instructions.
2020-04-19 16:14:13 -07:00
Simon Pilgrim 1824ae0f42 [X86] Remove defunct EmitLoweredAtomicFP declaration. NFC. 2020-04-10 17:05:07 +01:00
Simon Pilgrim dd84a2f77a [X86] Remove defunct emitFMA3Instr declaration. NFC. 2020-04-10 17:05:06 +01:00
Matt Arsenault 84aa58cbe2 CodeGen: Use Register in TargetLowering 2020-04-08 12:10:58 -04:00
Scott Constable 71e8021d82 [X86][NFC] Generalize the naming of "Retpoline Thunks" and related code to "Indirect Thunks"
There are applications for indirect call/branch thunks other than retpoline for Spectre v2, e.g.,

https://software.intel.com/security-software-guidance/software-guidance/load-value-injection

Therefore it makes sense to refactor X86RetpolineThunks as a more general capability.

Differential Revision: https://reviews.llvm.org/D76810
2020-04-02 21:55:13 -07:00
Guillaume Chatelet c7468c1696 [Alignment][NFC] Use Align in SelectionDAG::getMemIntrinsicNode
Summary:
This is patch is part of a series to introduce an Alignment type.
See this thread for context: http://lists.llvm.org/pipermail/llvm-dev/2019-July/133851.html
See this patch for the introduction of the type: https://reviews.llvm.org/D64790

Reviewers: courbet

Subscribers: jholewinski, nemanjai, hiraditya, kbarton, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D77149
2020-04-01 09:32:05 +00:00
Craig Topper f92563f907 [VectorUtils][X86] De-templatize scaleShuffleMask and 2 X86 shuffle mask helpers and move their implementation to cpp files
Summary: These were templated due to SelectionDAG using int masks for shuffles and IR using unsigned masks for shuffles. But now that D72467 has landed we have an int mask version of IRBuilder::CreateShuffleVector. So just use int instead of a template

Reviewers: spatel, efriedma, RKSimon

Reviewed By: efriedma

Subscribers: hiraditya, llvm-commits

Differential Revision: https://reviews.llvm.org/D77183
2020-04-01 00:46:48 -07:00
Simon Pilgrim 950ea61653 [X86] Remove orphan LowerSTRICT_FSETCC declaration. NFCI.
LowerSETCC handles strict cases as well, we don't have a separate function.
2020-03-27 17:03:19 +00:00
Sanjay Patel 0eeee83d75 [VectorUtils] move x86's scaleShuffleMask to generic VectorUtils
We have some long-standing missing shuffle optimizations that could
use this transform via VectorCombine now:
https://bugs.llvm.org/show_bug.cgi?id=35454
(and we still don't get that case in the backend either)

This function is apparently templated because there's existing code
in IR that treats mask values as unsigned and backend code that
treats masks values as signed.

The mask values are not endian-dependent (as shown by the existing
bitcast transform from DAGCombiner).

Differential Revision: https://reviews.llvm.org/D76508
2020-03-23 09:58:55 -04:00
Simon Pilgrim e43a085781 [X86] X86::isConstantSplat - enable partial undef bit handling by default.
We currently only ever use this for lowering constant uniform values (shift/rotate by immediate) so we can safely enable it by default (it treats the undef bits as zero when extracting constants).

This is necessary for an upcoming patch that will use SimplifyDemandedBits more aggressively on funnel shift amounts and causes regressions in vXi64 constant without it.
2020-03-16 12:56:24 +00:00
Simon Pilgrim b3b4727a3e [X86] Replace (most) X86ISD::SHLD/SHRD usage with ISD::FSHL/FSHR generic opcodes (PR39467)
For i32 and i64 cases, X86ISD::SHLD/SHRD are close enough to ISD::FSHL/FSHR that we can use them directly, we just need to account for the operand commutation for SHRD.

The i16 SHLD/SHRD case is annoying as the shift amount is modulo-32 (vs funnel shift modulo-16), so I've added X86ISD::FSHL/FSHR equivalents, which matches the generic implementation in all other terms.

Something I'm slightly concerned with is that ISD::FSHL/FSHR legality is controlled by the Subtarget.isSHLDSlow() feature flag - we don't normally use non-ISA features for this but it allows the DAG combines to continue to operate after legalization in a lot more cases.

The X86 *bits.ll changes are all affected by the same issue - we now have a "FSHR(-1,-1,amt) -> ROTR(-1,amt) -> (-1)" simplification that reduces the dependencies enough for the branch fall through code to mess up.

Differential Revision: https://reviews.llvm.org/D75748
2020-03-11 11:17:49 +00:00
Simon Pilgrim f90cc633de Fix cppcheck definition/declaration arg mismatch warnings. NFCI. 2020-02-27 14:35:20 +00:00