Commit Graph

198 Commits

Author SHA1 Message Date
Arthur Eubanks 309d453866 [llvm-reduce] Move most debugging output behind --verbose
This should cut down on the visual noise when reducing. Still keep output when we run a pass or when we successfully reduce.

Notably, this also suppresses redirecting the test output to stdout/stderr.

Reviewed By: regehr

Differential Revision: https://reviews.llvm.org/D131922
2022-08-19 13:25:42 -07:00
Eli Friedman cfd2c5ce58 Untangle the mess which is MachineBasicBlock::hasAddressTaken().
There are two different senses in which a block can be "address-taken".
There can be a BlockAddress involved, which means we need to map the
IR-level value to some specific block of machine code.  Or there can be
constructs inside a function which involve using the address of a basic
block to implement certain kinds of control flow.

Mixing these together causes a problem: if target-specific passes are
marking random blocks "address-taken", if we have a BlockAddress, we
can't actually tell which MachineBasicBlock corresponds to the
BlockAddress.

So split this into two separate bits: one for BlockAddress, and one for
the machine-specific bits.

Discovered while trying to sort out related stuff on D102817.

Differential Revision: https://reviews.llvm.org/D124697
2022-08-16 16:15:44 -07:00
John Regehr 2f1fa6242a this pass calls simplifyCFG on individual basic blocks; we want this
so that we can reduce away incidental parts of the CFG in cases where
the full simplifyCFG pass makes the test case uninteresting

Differential Revision: https://reviews.llvm.org/D131920
2022-08-15 15:45:20 -06:00
Arthur Eubanks 853b57fe80 [NFC][llvm-reduce] Use new pass manager for printing ThinLTO bitcode 2022-08-15 14:14:08 -07:00
John Regehr df308cab28 fix some bad logic that was removing all successor phi nodes, not just
out of chunk ones. the non-default second argument to
removePredecessor() is necessary to avoid creating invalid IR on
examples like the one in the provided test case

Differential Revision: https://reviews.llvm.org/D131843
2022-08-13 19:15:26 -06:00
Arthur Eubanks 195087d815 [llvm-reduce] Try harder to not create invalid aliases
This was done by adding --abort-on-invalid-reduction to remove-function-bodies-used-in-globals.ll and fixing the fallout.

Aliases must have a GlobalValue or ConstantExpr aliasee and the aliasee must be a definition if it's a GlobalValue.
Don't RAUW functions with null if there's an alias pointing to it, and similarly don't delete the body of a function.
Don't delete the entire body of a function when reducing blocks, preserve at least one block.

Also make debugging these sorts of things easier by dumping the module when --abort-on-invalid-reduction triggers.

Reviewed By: regehr

Differential Revision: https://reviews.llvm.org/D131505
2022-08-12 10:39:05 -07:00
Arthur Eubanks bd1f80f54e [llvm-reduce] Add delta pass to run IR passes
The exact IR passes run is customizable via `-ir-passes`.

Reviewed By: regehr

Differential Revision: https://reviews.llvm.org/D123749
2022-08-12 10:38:19 -07:00
John Regehr 213c21fe10 earlier I fixed a bug where the BB removal pass sometimes created
invalid IR. the fix was incomplete, this one is better and is believed
to be complete

Differential Revision: https://reviews.llvm.org/D131132
2022-08-04 10:21:20 -06:00
John Regehr 5b4f6d8b4b prevent llvm-reduce from duplicating values in switch cases when turning operands into zero or one 2022-08-03 10:06:45 -06:00
John Regehr 1116fa4765 avoid a bug where we remove a BB and then the next one becomes the
entry block and is illegal due to having more then one predecessor
block

Differential Revision: https://reviews.llvm.org/D131026
2022-08-02 22:23:12 -06:00
John Regehr 71d1bd1457 llvm-reduce: reorder passes to run the ones first that delete function bodies; this makes reductions go faster 2022-08-02 10:32:49 -06:00
Matt Arsenault fe1678d1b2 llvm-reduce: Fix register mask test
This was sometimes failing with "input module no longer interesting
after counting chunks" assert.
2022-07-20 18:19:14 -04:00
Matt Arsenault e24b390dbc llvm-reduce: Add reduction for instruction defs
Try to insert an implicit_def to replace the instruction's value,
replacing the original instruction's def with a dead register. If all
defs are delete the instruction entirely.

This is pretty similar to the instruction reduction, but leaves the
new defs in the same place as the original instruction. This could
possibly replace it. I'm not sure if we should directly delete the
instructions here, or leave dead ones behind.

This could also further work to replace physical register defs.
2022-07-18 13:41:08 -04:00
Matt Arsenault 0f9d9edd24 llvm-reduce: Add reduction for custom register masks
I have a register allocator failure that only reproduces with IPRA
enabled, and requires the specific regmask if I want to only run the
one relevant pass. The printed custom regmask is enormous and I would
like to reduce it.

This reduces each individual bit in the mask, but it would probably be
better to start at register units and clear all aliasing fields at a
time. This would require stricter verification that all aliasing bits
are set in regmasks (although I would prefer to switch regmasks to use
register units in the first place).
2022-07-18 13:41:08 -04:00
Kazu Hirata 3112987d5c Remove unused forward declarations (NFC) 2022-07-17 15:37:48 -07:00
owenca cd434a202c [llvm] Wrap multi-statement macro definitions with do ... while (0) 2022-07-16 20:58:20 -07:00
Fraser Cormack bb3f99cd85 [llvm-reduce] Fix crash when reducing integer vectors to 1
Integer vectors were previously ignored when reducing operands. When
6b8bd0f72 introduced support for reducing floating-point
scalars/vectors, the vector case was written to only handle
floating-point values. It would crash when creating an invalid
ConstantFP from the integer element type.

Instead of reinstating the old integer vector behaviour, we might as
well reduce integer vectors to all-one splats.

A couple of existing tests has also been renamed from "remove" to
"reduce" to better reflect the deltas they test.

Reviewed By: arsenm

Differential Revision: https://reviews.llvm.org/D129629
2022-07-13 16:56:55 +01:00
Matthew Voss c4960f6363 [llvm-reduce] Change initialization order to fix bots. NFC
Fixes this error:
/var/lib/buildbot/sanitizer-buildbot6/sanitizer-x86_64-linux-android/build/
llvm-project/llvm/tools/llvm-reduce/TestRunner.cpp:20:7:
error: field 'TM' will be initialized after field 'ToolName'
[-Werror,-Wreorder-ctor]
      TM(std::move(TM)), ToolName(ToolName) {
      ^~~~~~~~~~~~~~~~~  ~~~~~~~~~~~~~~~~~~
      Program(std::move(Program)) TM(std::move(TM))
1 error generated.

https://lab.llvm.org/buildbot/\#/builders/77/builds/19154
2022-06-30 09:56:47 -07:00
Matthew Voss 6b3956e123 [llvm-reduce] Add support for LTO bitcode files
Adds support for reading and writing LTO bitcode files.

  - Emit a summary if the original bitcode file had a summary
  - Use split LTO units if the original bitcode file used them.

Reviewed By: arsenm

Differential Revision: https://reviews.llvm.org/D127168
2022-06-30 08:58:24 -07:00
Matt Arsenault 261075590b llvm-reduce: Handle reducing FP values to nan
Prefer 0/1 over NaN, but it may make more sense to invert this as FP
operations with nan inputs can universally be folded into something
else.
2022-06-27 19:55:38 -04:00
Matt Arsenault 62b5aa984e llvm-reduce: Check shouldKeep before trying to reduce operands
No point doing the more complicated check first.
2022-06-27 13:16:15 -04:00
John Regehr 2962f9df7c stop llvm-reduce from introducing undefs
Differential Revision: https://reviews.llvm.org/D128317
2022-06-22 20:41:23 -06:00
John Regehr 8771023543 in the absense of the -max-pass-iterations command line options, make
llvm-reduce run its full pass sequence up to 5 times, instead of just
once

Differential Revision: https://reviews.llvm.org/D128284
2022-06-21 10:47:42 -06:00
Kazu Hirata 064a08cd95 Don't use Optional::hasValue (NFC) 2022-06-20 20:05:16 -07:00
Matt Arsenault 32bd0c1714 llvm-reduce: Try to fix dynamic libraries build 2022-06-16 21:48:04 -04:00
Matt Arsenault eea11e7369 llvm-reduce: Add reduction pass to simplify instructions 2022-06-16 20:39:27 -04:00
Matt Arsenault 6b8bd0f72d llvm-reduce: Support replacing FP values with 1.0 2022-06-16 20:13:17 -04:00
Matt Arsenault cbbc7e4a75 llvm-reduce: Don't set generic instruction operands to undef
The intention is that these should never have undef operands. It turns
out the restriction the verifier enforces is too lax. The verifier
enforces that registers without a register class cannot be undef, but
it's valid to use a register with a register class and type. The
verifier needs to change to be based on the opcode.
2022-06-07 10:28:23 -04:00
Matt Arsenault 47c8ec811f llvm-reduce: Add pass to remove register uses
Try to delete implicit uses, and add undef flags to explicit ones.
2022-06-07 10:28:23 -04:00
Matt Arsenault cc5a1b3dd9 llvm-reduce: Add cloning of target MachineFunctionInfo
MIR support is totally unusable for AMDGPU without this, since the set
of reserved registers is set from fields here.

Add a clone method to MachineFunctionInfo. This is a subtle variant of
the copy constructor that is required if there are any MIR constructs
that use pointers. Specifically, at minimum fields that reference
MachineBasicBlocks or the MachineFunction need to be adjusted to the
values in the new function.
2022-06-07 10:14:48 -04:00
Matt Arsenault e6723d80c7 llvm-reduce: Fix crashes on unreachable blocks for MIR instructions 2022-06-07 10:00:26 -04:00
Matt Arsenault 56303223ac llvm-reduce: Don't assert on functions which don't track liveness
Use the query that doesn't assert if TracksLiveness isn't set, which
needs to always be available. We also need to start printing liveins
regardless of TracksLiveness.
2022-06-07 10:00:25 -04:00
Fangrui Song d0d1c416cb Remove unneeded cl::ZeroOrMore for cl::list options 2022-06-04 23:51:13 -07:00
Kazu Hirata 4969a6924d Use llvm::less_first (NFC) 2022-06-04 21:23:18 -07:00
Clemens Wasser 42c7f494d9 [tools] Forward declare classes & remove includes
Reviewed By: MaskRay

Differential Revision: https://reviews.llvm.org/D120208
2022-06-03 16:32:04 -07:00
Matt Arsenault a0dcbe45bd llvm-reduce: Add reduction pass to remove regalloc hints
I'm a bit confused by what's actually stored for the allocation
hints. The MIR parser only handles the "simple" case where there's a
single hint. I don't really understand the assertion in
clearSimpleHint, or under what circumstances there are multiple hint
registers.
2022-06-01 09:15:41 -04:00
Matt Arsenault 2011052150 llvm-reduce: Add pass to reduce MIR instruction flags 2022-06-01 08:58:34 -04:00
Balazs Benics a73b50ad06 Revert "[llvm][clang][bolt][NFC] Use llvm::less_first() when applicable"
This reverts commit 3988bd1398.

Did not build on this bot:
https://lab.llvm.org/buildbot#builders/215/builds/6372

/usr/include/c++/9/bits/predefined_ops.h:177:11: error: no match for call to
‘(llvm::less_first) (std::pair<long unsigned int, llvm::bolt::BinaryBasicBlock*>&, const std::pair<long unsigned int, std::nullptr_t>&)’
  177 |  { return bool(_M_comp(*__it, __val)); }
2022-05-27 11:19:18 +02:00
Balazs Benics 3988bd1398 [llvm][clang][bolt][NFC] Use llvm::less_first() when applicable
One could reuse this functor instead of rolling out your own version.
There were a couple other cases where the code was similar, but not
quite the same, such as it might have an assertion in the lambda or other
constructs. Thus, I've not touched any of those, as it might change the
behavior in some way.

As per https://discourse.llvm.org/t/submitting-simple-nfc-patches/62640/3?u=steakhal
Chris Lattner
> LLVM intentionally has a “yes, you can apply common sense judgement to
> things” policy when it comes to code review. If you are doing mechanical
> patches (e.g. adopting less_first) that apply to the entire monorepo,
> then you don’t need everyone in the monorepo to sign off on it. Having
> some +1 validation from someone is useful, but you don’t need everyone
> whose code you touch to weigh in.

Differential Revision: https://reviews.llvm.org/D126068
2022-05-27 11:15:23 +02:00
Markus Lavin bb8e02325f llvm-reduce: improve basic-blocks removal pass
When the single branch target of a block has been removed try updating
it to target a  block that is kept (by scanning forward in the sequence)
instead of replacing the branch with a return instruction. Doing so
reduces the risk of breaking loop structures meaning that when the loop
is 'interesting' these reductions should have more blocks eliminated.

Differential Revision: https://reviews.llvm.org/D125766
2022-05-24 09:51:25 +02:00
Matt Arsenault 241ca47db5 llvm-reduce: Reduce includes 2022-05-04 00:05:15 +01:00
Matt Arsenault aabea3b2ea llvm-reduce: Fix not removing first instruction in MachineBasicBlock
This had the surprising behavior of using whatever instruction
happened to be first in the block as an anchor point to stick random
implicit defs on. Use a real implicit_def instead.
2022-05-01 18:26:45 -04:00
Matt Arsenault 35264e7179 llvm-reduce: Introduce new scoring mechanism for MIR reductions
Many MIR reductions benefit from or require increasing the instruction
count. For example, unlike in the IR, you may need to insert a new
instruction to represent an undef. The current instruction reduction
pass works around this by sticking implicit defs on whatever
instruction happens to be first in the entry block block.

Other strategies I've applied manually include breaking instructions
with multiple defs into separate instructions, or breaking large
register defs into multiple subregister defs.

Make up a simple scoring system based on what I generally try to get
rid of first when manually reducing. Counts implicit defs as free
since reduction passes will be introducing them, although they
probably should count for something. It also might make more sense to
have a comparison the two functions, rather than having to compute a
contextless number. This isn't particularly well tested since overall
the MIR support isn't in a place where it is useful on the kinds of
testcases I want to throw at it.
2022-05-01 18:24:04 -04:00
Matt Arsenault 0b896b754e llvm-reduce: Do not try to delete frame instructions
The verifier enforces these appearing as balanced pairs, so just
deleting one has no real chance of producing something valid.
2022-05-01 18:21:52 -04:00
Matt Arsenault 3939e99aae llvm-reduce: Add pass to reduce IR references from MIR
This is typically the first thing I do when reducing a new testcase
until the IR section can be deleted.
2022-05-01 17:40:53 -04:00
Matt Arsenault 717209763e llvm-reduce: Fix incorrect cloning of MachineMemOperands
There were two problems with directly copying the MMOs from the old
function. The MMOs are owned by the function's Allocator, so need to
be reallocated anyways (surprisingly I didn't notice breakage on
this). Second, the PseudoSourceValues are also allocated per function
and need to be reallocated.
2022-04-27 18:51:38 -04:00
Matt Arsenault e39e9d339c llvm-reduce: Fix crashing on file opening error for mir path 2022-04-27 18:15:12 -04:00
Matt Arsenault 7c2db66632 llvm-reduce: Support multiple MachineFunctions
The current testcase I'm trying to reduce only reproduces with IPRA
enabled and requires handling multiple functions.

The only real difference vs. the IR is the extra indirect to look for
the underlying MachineFunction, so treat the ReduceWorkItem as the
module instead of the function.

The ugliest piece of this is really the ugliness of
MachineModuleInfo. It not only tracks actual module state, but has a
number of transient fields used for isel and/or the asm printer. These
shouldn't do any harm for the use here, though they should be
separated out.
2022-04-27 18:11:59 -04:00
Matt Arsenault 1747a93b28 llvm-reduce: Try to parse triple/datalayout from module
This saves needing to specify -mtriple on nearly every use for MIR
reduction.
2022-04-27 17:47:46 -04:00
Matt Arsenault 18b9c46370 llvm-reduce: Fix not cloning MachineInstr flags 2022-04-27 17:29:18 -04:00