[all-commits] [llvm/llvm-project] 231026: [Attributor] Inititialize "value attributes" w/ mu...

[Johannes Doerfert via All-commits]

  Branch: refs/heads/master
  Home:   https://github.com/llvm/llvm-project
  Commit: 231026a508eacad3a9bab98954194287b8fcd412
      https://github.com/llvm/llvm-project/commit/231026a508eacad3a9bab98954194287b8fcd412
  Author: Johannes Doerfert <johannes at jdoerfert.de>
  Date:   2020-05-03 (Sun, 03 May 2020)

  Changed paths:
    M llvm/lib/Transforms/IPO/AttributorAttributes.cpp
    M llvm/test/Transforms/Attributor/ArgumentPromotion/attrs.ll
    M llvm/test/Transforms/Attributor/ArgumentPromotion/byval-2.ll
    M llvm/test/Transforms/Attributor/ArgumentPromotion/byval.ll
    M llvm/test/Transforms/Attributor/ArgumentPromotion/control-flow2.ll
    M llvm/test/Transforms/Attributor/ArgumentPromotion/fp80.ll
    M llvm/test/Transforms/Attributor/ArgumentPromotion/live_called_from_dead_2.ll
    M llvm/test/Transforms/Attributor/ArgumentPromotion/musttail.ll
    M llvm/test/Transforms/Attributor/ArgumentPromotion/tail.ll
    M llvm/test/Transforms/Attributor/IPConstantProp/2009-09-24-byval-ptr.ll
    M llvm/test/Transforms/Attributor/IPConstantProp/openmp_parallel_for.ll
    M llvm/test/Transforms/Attributor/callbacks.ll
    M llvm/test/Transforms/Attributor/read_write_returned_arguments_scc.ll
    M llvm/test/Transforms/Attributor/value-simplify.ll

  Log Message:
  -----------
  [Attributor] Inititialize "value attributes" w/ must-be-executed-context info

Attributes that only depend on the value (=bit pattern) can be
initialized from uses in the must-be-executed-context (MBEC). We did use
`AAComposeTwoGenericDeduction` and `AAFromMustBeExecutedContext` before
to do this for some positions of these attributes but not for all. This
was fairly complicated and also problematic as we did run it in every
`updateImpl` call even though we only use known information. The new
implementation removes `AAComposeTwoGenericDeduction`* and
`AAFromMustBeExecutedContext` in favor of a simple interface
`AddInformation::fromMBEContext(...)` which we call from the
`initialize` methods of the "value attribute" `Impl` classes, e.g.
`AANonNullImpl:initialize`.

There can be two types of test changes:
  1) Artifacts were we miss some information that was known before a
     global fixpoint was reached and therefore available in an update
     but not at the beginning.
  2) Deduction for values we did not derive via the MBEC before or which
     were not found as the `AAFromMustBeExecutedContext::updateImpl` was
     never invoked.

* An improved version of AAComposeTwoGenericDeduction can be found in
  D78718. Once we find a new use case that implementation will be able
  to handle "generic" AAs better.

---

Single run of the Attributor module and then CGSCC pass (oldPM)
for SPASS/clause.c (~10k LLVM-IR loc):

Before:
```
calls to allocation functions: 468428 (328952/s)
temporary memory allocations: 77480 (54410/s)
peak heap memory consumption: 32.71MB
peak RSS (including heaptrack overhead): 122.46MB
total memory leaked: 269.10KB
```

After:
```
calls to allocation functions: 554720 (351310/s)
temporary memory allocations: 101650 (64376/s)
peak heap memory consumption: 28.46MB
peak RSS (including heaptrack overhead): 116.75MB
total memory leaked: 269.10KB
```

Difference:
```
calls to allocation functions: 86292 (556722/s)
temporary memory allocations: 24170 (155935/s)
peak heap memory consumption: -4.25MB
peak RSS (including heaptrack overhead): 0B
total memory leaked: 0B
```

Reviewed By: uenoku

Differential Revision: https://reviews.llvm.org/D78719