Move the code which adjusts the immediate/predicate on a G_ICMP to
AArch64PostLegalizerLowering.
This
- Reduces the number of places we need to test for optimized compares in the
selector. We know that the compare should have been simplified by the time it
hits the selector, so we can avoid testing this in selects, brconds, etc.
- Allows us to potentially fold more compares (previously, this optimization
was only done after calling `tryFoldCompare`, this may allow us to hit some more
TST cases)
- Simplifies the selection code in `emitIntegerCompare` significantly; we can
just use an emitSUBS function.
- Allows us to avoid checking that the predicate has been updated after
`emitIntegerCompare`.
Also add a utility header file for things that may be useful in the selector
and various combiners. No need for an implementation file at this point, since
it's just one constexpr function for now. I've run into a couple cases where
having one of these would be handy, so might as well add it here. There are
a couple functions in the selector that can probably be factored out into
here.
Differential Revision: https://reviews.llvm.org/D89823
These cause problems for later optimizations, just using an unused vreg like
SelectionDAG generates better code in the end, and obviates the need for some
GISel specific flag optimizations.
Differential Revision: https://reviews.llvm.org/D89419
Similar to code in `getAArch64Cmp` in AArch64ISelLowering.
When we get a compare against a constant, sometimes, that constant isn't valid
for selecting an immediate form.
However, sometimes, you can get a valid constant by adding 1 or subtracting 1,
and updating the condition code.
This implements the following transformations when valid:
- x slt c => x sle c - 1
- x sge c => x sgt c - 1
- x ult c => x ule c - 1
- x uge c => x ugt c - 1
- x sle c => x slt c + 1
- x sgt c => s sge c + 1
- x ule c => x ult c + 1
- x ugt c => s uge c + 1
Valid meaning the constant doesn't wrap around when we fudge it, and the result
gives us a compare which can be selected into an immediate form.
This also moves `getImmedFromMO` higher up in the file so we can use it.
Differential Revision: https://reviews.llvm.org/D78769
Summary:
This catches malformed mir files which specify alignment as log2 instead of pow2.
See https://reviews.llvm.org/D65945 for reference,
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: MatzeB, qcolombet, dschuff, arsenm, sdardis, nemanjai, jvesely, nhaehnle, hiraditya, kbarton, asb, rbar, johnrusso, simoncook, apazos, sabuasal, niosHD, jrtc27, MaskRay, zzheng, edward-jones, atanasyan, rogfer01, MartinMosbeck, brucehoult, the_o, PkmX, jocewei, jsji, Petar.Avramovic, asbirlea, s.egerton, pzheng, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D67433
llvm-svn: 371608
This teaches `tryOptSelect` to handle folding G_ICMP, and removes the
requirement that the G_SELECT we're dealing with is floating point.
Some refactoring to make this work nicely as well:
- Factor out the scalar case from the selection code for G_ICMP into
`emitIntegerCompare`.
- Make `tryOptCMN` return a MachineInstr* instead of a bool.
- Make `tryOptCMN` not modify the instruction being selected.
- Factor out the CMN emission into `emitCMN` for readability.
By doing this this way, we can get all of the compare selection optimizations
in select emission.
Differential Revision: https://reviews.llvm.org/D64084
llvm-svn: 364961
Jessica Paquette