15 Commits

Author SHA1 Message Date
Eli Friedman
bc7f11ccb0 [SelectionDAG] Improve expansion of wide min/max
The current implementation tries to handle the high and low halves
separately, but that's less efficient in most cases; use a wide SETCC
instead.

Differential Revision: https://reviews.llvm.org/D151358
2023-06-26 10:45:41 -07:00
Craig Topper
139392c0a5 [LegalizeTypes][ARM][AArch6][RISCV][VE][WebAssembly] Add special case for smin(X, -1) and smax(X, 0) to ExpandIntRes_MINMAX.
We can compute a simpler expression for Lo for these cases. This
is an alternative for the test cases in D151180 that works for
more targets.

This is similar to some of the special cases we have for expanding
setcc operands.

Differential Revision: https://reviews.llvm.org/D151182
2023-05-23 09:19:55 -07:00
Samuel Parker
f48d3b6f46 Revert "[DAGCombine] Fold redundant select"
This reverts commit c7f9344d0f8f6a00adab138037e2e7b406ef2b69.
2023-02-23 17:59:41 +00:00
Samuel Parker
c7f9344d0f [DAGCombine] Fold redundant select
Recommit bbdf24357932b064f2aa18ea1356b474e0220dde.

Original commit message:

If a chain of two selects share a true/false value and are controlled
by two setcc nodes, that are never both true, we can fold away one of
the selects. So, the following:
(select (setcc X, const0, eq), Y,
  (select (setcc X, const1, eq), Z, Y))

Can be combined to:
  select (setcc X, const1, eq) Z, Y

Differential Revision: https://reviews.llvm.org/D142535
2023-02-15 10:32:16 +00:00
Samuel Parker
91f8289ff0 Revert "[DAGCombine] Fold redundant select"
This reverts commit bbdf24357932b064f2aa18ea1356b474e0220dde.
2023-02-07 10:37:20 +00:00
Samuel Parker
bbdf243579 [DAGCombine] Fold redundant select
If a chain of two selects share a true/false value and are controlled
by two setcc nodes, that are never both true, we can fold away one of
the selects. So, the following:
(select (setcc X, const0, eq), Y,
  (select (setcc X, const1, eq), Z, Y))

Can be combined to:
  select (setcc X, const1, eq) Z, Y

Differential Revision: https://reviews.llvm.org/D142535
2023-02-02 09:43:21 +00:00
Luke Lau
f841ad30d7 [WebAssembly] Replace LOAD_SPLAT with SPLAT_VECTOR
Splats were selected by matching on uses of `build_vector` with
identical elements, but a while back a target independent node for
vector splatting was added.
This removes the WebAssembly specific LOAD_SPLAT intrinsic, and instead
makes SPLAT_VECTOR legal and adds patterns for splat loads.

Differential Revision: https://reviews.llvm.org/D139871
2023-01-04 15:07:47 +00:00
Fanchen Kong
28557e8c98 [WebAssembly] Improve codegen for shuffles with undefined lane indices
For undefined lane indices, fill the mask with {0..N} instead of zeros to allow
further reduction to word/dword shuffle on the VM.

Reviewed By: tlively, penzn

Differential Revision: https://reviews.llvm.org/D133473
2022-09-13 16:03:18 -07:00
David Green
57356d6bb7 [DAG] Create fptoui.sat from clamped fptoui
This is the unsigned variant of D111976, where we convert a clamped
fptoui to a fptoui.sat. Because we are unsigned, the condition this time
is only UMIN of UINT_MAX. Similarly to D111976 it handles ISD::UMIN,
ISD::SETCC/ISD::SELECT, ISD::VSELECT or ISD::SELECT_CC nodes.

This especially helps on ARM/AArch64 where the vcvt instructions
naturally saturate the result.

Differential Revision: https://reviews.llvm.org/D114964
2022-01-26 08:37:44 +00:00
Jing Bao
2a4a229d6d [WebAssembly] Custom optimization for truncate
When possible, optimize TRUNCATE to generate Wasm SIMD narrow
instructions (i16x8.narrow_i32x4_u, i8x16.narrow_i16x8_u), rather than generate
lots of extract_lane and replace_lane.

Closes #50350.
2021-12-14 08:42:39 -08:00
David Green
57ff805a6d [DAG] Create fptoui.sat from clamped fptosi
As an extension to D111976, this converts clamp fptosi, clamped between
0 and (2^n)-1 to a fptoui.sat. This can greatly help on targets with
conversions that naturally saturate, such as Arm.

X86 disables the transform as some of the test cases increases in size.
A fptoui.sat necessitates a fp clamp without native support, so there is
little use in converting if the instruction is just going to be
expanded.

Differential Revision: https://reviews.llvm.org/D112428
2021-12-05 09:25:52 +00:00
David Green
9e8a71caf0 [DAG] Create fptosi.sat from clamped fptosi
This adds a fold in DAGCombine to create fptosi_sat from sequences for
smin(smax(fptosi(x))) nodes, where the min/max saturate the output of
the fp convert to a specific bitwidth (say INT_MIN and INT_MAX). Because
it is dealing with smin(/smax) in DAG they may currently be ISD::SMIN,
ISD::SETCC/ISD::SELECT, ISD::VSELECT or ISD::SELECT_CC nodes which need
to be handled similarly.

A shouldConvertFpToSat method was added to control when converting may
be profitable. The original fptosi will have a less strict semantics
than the fptosisat, with less values that need to produce defined
behaviour.

This especially helps on ARM/AArch64 where the vcvt instructions
naturally saturate the result.

Differential Revision: https://reviews.llvm.org/D111976
2021-11-30 15:29:14 +00:00
Hans Wennborg
a87782c34d Revert "[DAG] Create fptosi.sat from clamped fptosi"
It causes builds to fail with this assert:

llvm/include/llvm/ADT/APInt.h:990:
bool llvm::APInt::operator==(const llvm::APInt &) const:
Assertion `BitWidth == RHS.BitWidth && "Comparison requires equal bit widths"' failed.

See comment on the code review.

> This adds a fold in DAGCombine to create fptosi_sat from sequences for
> smin(smax(fptosi(x))) nodes, where the min/max saturate the output of
> the fp convert to a specific bitwidth (say INT_MIN and INT_MAX). Because
> it is dealing with smin(/smax) in DAG they may currently be ISD::SMIN,
> ISD::SETCC/ISD::SELECT, ISD::VSELECT or ISD::SELECT_CC nodes which need
> to be handled similarly.
>
> A shouldConvertFpToSat method was added to control when converting may
> be profitable. The original fptosi will have a less strict semantics
> than the fptosisat, with less values that need to produce defined
> behaviour.
>
> This especially helps on ARM/AArch64 where the vcvt instructions
> naturally saturate the result.
>
> Differential Revision: https://reviews.llvm.org/D111976

This reverts commit 52ff3b009388f1bef4854f1b6470b4ec19d10b0e.
2021-11-30 15:36:56 +01:00
David Green
52ff3b0093 [DAG] Create fptosi.sat from clamped fptosi
This adds a fold in DAGCombine to create fptosi_sat from sequences for
smin(smax(fptosi(x))) nodes, where the min/max saturate the output of
the fp convert to a specific bitwidth (say INT_MIN and INT_MAX). Because
it is dealing with smin(/smax) in DAG they may currently be ISD::SMIN,
ISD::SETCC/ISD::SELECT, ISD::VSELECT or ISD::SELECT_CC nodes which need
to be handled similarly.

A shouldConvertFpToSat method was added to control when converting may
be profitable. The original fptosi will have a less strict semantics
than the fptosisat, with less values that need to produce defined
behaviour.

This especially helps on ARM/AArch64 where the vcvt instructions
naturally saturate the result.

Differential Revision: https://reviews.llvm.org/D111976
2021-11-30 11:05:32 +00:00
David Green
410d276400 [DAG] Add tests for fpsti.sat for various architectures. NFC 2021-11-29 21:57:13 +00:00