Commit Graph

15 Commits

Author SHA1 Message Date
Craig Topper 12d51f95fe [RISCV] Implement lround*/llround*/lrint*/llrint* with fcvt instruction with -fno-math-errno
These are fp->int conversions using either RMM or dynamic rounding modes.

The lround and lrint opcodes have a return type of either i32 or
i64 depending on sizeof(long) in the frontend which should follow
xlen. llround/llrint should always return i64 so we'll need a libcall
for those on rv32.

The frontend will only emit the intrinsics if -fno-math-errno is in
effect otherwise a libcall will be emitted which will not use
these ISD opcodes.

gcc also does this optimization.

Reviewed By: arcbbb

Differential Revision: https://reviews.llvm.org/D105206
2021-07-06 11:43:22 -07:00
Bjorn Pettersson 4c7f820b2b Update @llvm.powi to handle different int sizes for the exponent
This can be seen as a follow up to commit 0ee439b705,
that changed the second argument of __powidf2, __powisf2 and
__powitf2 in compiler-rt from si_int to int. That was to align with
how those runtimes are defined in libgcc.
One thing that seem to have been missing in that patch was to make
sure that the rest of LLVM also handle that the argument now depends
on the size of int (not using the si_int machine mode for 32-bit).
When using __builtin_powi for a target with 16-bit int clang crashed.
And when emitting libcalls to those rtlib functions, typically when
lowering @llvm.powi), the backend would always prepare the exponent
argument as an i32 which caused miscompiles when the rtlib was
compiled with 16-bit int.

The solution used here is to use an overloaded type for the second
argument in @llvm.powi. This way clang can use the "correct" type
when lowering __builtin_powi, and then later when emitting the libcall
it is assumed that the type used in @llvm.powi matches the rtlib
function.

One thing that needed some extra attention was that when vectorizing
calls several passes did not support that several arguments could
be overloaded in the intrinsics. This patch allows overload of a
scalar operand by adding hasVectorInstrinsicOverloadedScalarOpd, with
an entry for powi.

Differential Revision: https://reviews.llvm.org/D99439
2021-06-17 09:38:28 +02:00
Craig Topper d61b40ed27 [RISCV] Improve 64-bit integer materialization for some cases.
This adds a new integer materialization strategy mainly targeted
at 64-bit constants like 0xffffffff where there are 32 or more trailing
ones with leading zeros. We can materialize these by using an addi -1
and srli to restore the leading zeros. This matches what gcc does.

I haven't limited to just these cases though. The implementation
here takes the constant, shifts out all the leading zeros and
shifts ones into the LSBs, creates the new sequence, adds an srli,
and checks if this is shorter than our original strategy.

I've separated the recursive portion into a standalone function
so I could append the new strategy outside of the recursion. Since
external users are no longer using the recursive function, I've
cleaned up the external interface to return the sequence instead of
taking a vector by reference.

Reviewed By: asb

Differential Revision: https://reviews.llvm.org/D98821
2021-04-01 09:12:52 -07:00
Michael Munday e28b6a60bc [RISCV][NFC] Regenerate RISCV CodeGen tests
Regenerated using:

./llvm/utils/update_llc_test_checks.py -u llvm/test/CodeGen/RISCV/*.ll

This has added comments to spill-related instructions and added @plt to
some symbols.

Differential Revision: https://reviews.llvm.org/D92841
2020-12-09 19:42:49 +00:00
Craig Topper ed95cafbc5 [RISCV] Add an implementation of isFMAFasterThanFMulAndFAdd
Start with an assumption that FMA is faster than Fmul+FAdd. If thats not true
on some particular implementation we can add a tuning parameter in the future.

I've update the fmuladd test cases and added new test cases for fast math flag
based contraction.

Differential Revision: https://reviews.llvm.org/D91987
2020-11-25 15:07:34 -08:00
Luis Marques 3d0fbafd0b [RISCV] Switch to the Machine Scheduler
Most of the test changes are trivial instruction reorderings and differing
register allocations, without any obvious performance impact.

Differential Revision: https://reviews.llvm.org/D66973

llvm-svn: 372106
2019-09-17 11:15:35 +00:00
Luis Marques 2d550d19b3 Revert Patch from Phabricator
This reverts r372092 (git commit e38695a025)

llvm-svn: 372104
2019-09-17 10:52:09 +00:00
Luis Marques e38695a025 Patch from Phabricator
llvm-svn: 372092
2019-09-17 09:43:08 +00:00
Alex Bradbury 8a70468a27 [RISCV] Only mark fp as reserved if the function has a dedicated frame pointer
This follows similar logic in the ARM and Mips backends, and allows the free
use of s0 in functions without a dedicated frame pointer. The changes in
callee-saved-gprs.ll most clearly show the effect of this patch.

llvm-svn: 356063
2019-03-13 16:33:45 +00:00
Alex Bradbury 7539fa2c2d [RISCV] Implement RV64D codegen
This patch:
* Adds necessary RV64D codegen patterns
* Modifies CC_RISCV so it will properly handle f64 types (with soft float ABI)

Note that in general there is no reason to try to select fcvt.w[u].d rather than fcvt.l[u].d for i32 conversions because fptosi/fptoui produce poison if the input won't fit into the target type.

Differential Revision: https://reviews.llvm.org/D53237

llvm-svn: 352833
2019-02-01 03:53:30 +00:00
Alex Bradbury 0092df0669 [RISCV] Add target DAG combine for bitcast fabs/fneg on RV32FD
DAGCombiner::visitBITCAST will perform:
 fold (bitconvert (fneg x)) -> (xor (bitconvert x), signbit)
 fold (bitconvert (fabs x)) -> (and (bitconvert x), (not signbit))

As shown in double-bitmanip-dagcombines.ll, this can be advantageous. But
RV32FD doesn't use bitcast directly (as i64 isn't a legal type), and instead
uses RISCVISD::SplitF64. This patch adds an equivalent DAG combine for
SplitF64.

llvm-svn: 352247
2019-01-25 21:55:48 +00:00
Alex Bradbury 919f5fb8ca [RISCV] Add support for the various RISC-V FMA instruction variants
Adds support for the various RISC-V FMA instructions (fmadd, fmsub, fnmsub, fnmadd).

The criteria for choosing whether a fused add or subtract is used, as well as
whether the product is negated or not, is whether some of the arguments to the
llvm.fma.* intrinsic are negated or not. In the tests, extraneous fadd
instructions were added to avoid the negation being performed using a xor
trick, which prevented the proper FMA forms from being selected and thus
tested.

The FMA instruction patterns might seem incorrect (e.g., fnmadd: -rs1 * rs2 -
rs3), but they should be correct. The misleading names were inherited from
MIPS, where the negation happens after computing the sum.

The llvm.fmuladd.* intrinsics still do not generate RISC-V FMA instructions,
as that depends on TargetLowering::isFMAFasterthanFMulAndFAdd.

Some comments in the test files about what type of instructions are there
tested were updated, to better reflect the current content of those test
files.

Differential Revision: https://reviews.llvm.org/D54205
Patch by Luís Marques.

llvm-svn: 349023
2018-12-13 10:49:05 +00:00
Alex Bradbury 52c27785ce [RISCV] Add some missing expansions for floating-point intrinsics
A number of intrinsics, such as llvm.sin.f32, would result in a failure to 
select. This patch adds expansions for the relevant selection DAG nodes, as 
well as exhaustive testing for all f32 and f64 intrinsics.

The codegen for FMA remains a TODO item, pending support for the various 
RISC-V FMA instruction variants.

The llvm.minimum.f32.* and llvm.maximum.* tests are commented-out, pending 
upstream support for target-independent expansion, as discussed in 
http://lists.llvm.org/pipermail/llvm-dev/2018-November/127408.html.

Differential Revision: https://reviews.llvm.org/D54034
Patch by Luís Marques.

llvm-svn: 346034
2018-11-02 19:50:38 +00:00
Shiva Chen d58bd8dc4a [RISCV] Expand function call to "call" pseudoinstruction
To do this:
1. Change GlobalAddress SDNode to TargetGlobalAddress to avoid legalizer
   split the symbol.

2. Change ExternalSymbol SDNode to TargetExternalSymbol to avoid legalizer
   split the symbol.

3. Let PseudoCALL match direct call with target operand TargetGlobalAddress
   and TargetExternalSymbol.

Differential Revision: https://reviews.llvm.org/D44885

llvm-svn: 330827
2018-04-25 14:19:12 +00:00
Alex Bradbury 8f296478eb [RISCV] Add tests missed in r329871
llvm-svn: 329872
2018-04-12 05:36:44 +00:00