[all-commits] [llvm/llvm-project] 95e0d2: [Attributor] Remember only necessary dependences

[Johannes Doerfert via All-commits]

  Branch: refs/heads/master
  Home:   https://github.com/llvm/llvm-project
  Commit: 95e0d28b71e42c9b7cd77c96f728311981a021f6
      https://github.com/llvm/llvm-project/commit/95e0d28b71e42c9b7cd77c96f728311981a021f6
  Author: Johannes Doerfert <johannes at jdoerfert.de>
  Date:   2020-05-03 (Sun, 03 May 2020)

  Changed paths:
    M llvm/include/llvm/Transforms/IPO/Attributor.h
    M llvm/lib/Transforms/IPO/Attributor.cpp
    M llvm/lib/Transforms/IPO/AttributorAttributes.cpp
    M llvm/test/Transforms/Attributor/ArgumentPromotion/2008-07-02-array-indexing.ll
    M llvm/test/Transforms/Attributor/ArgumentPromotion/control-flow.ll
    M llvm/test/Transforms/Attributor/IPConstantProp/PR16052.ll
    M llvm/test/Transforms/Attributor/IPConstantProp/openmp_parallel_for.ll
    M llvm/test/Transforms/Attributor/nocapture-1.ll
    M llvm/test/Transforms/Attributor/nonnull.ll
    M llvm/test/Transforms/Attributor/range.ll
    M llvm/test/Transforms/Attributor/undefined_behavior.ll
    M llvm/test/Transforms/Attributor/willreturn.ll

  Log Message:
  -----------
  [Attributor] Remember only necessary dependences

Before we eagerly put dependences into the QueryMap as soon as we
encountered them (via `Attributor::getAAFor<>` or
`Attributor::recordDependence`). Now we will wait to see if the
dependence is useful, that is if the target is not already in a fixpoint
state at the end of the update. If so, there is no need to record the
dependence at all.

Due to the abstraction via `Attributor::updateAA` we will now also treat
the very first update (during attribute creation) as we do subsequent
updates.

Finally this resolves the problematic usage of QueriedNonFixAA.

---

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

Before:
```
calls to allocation functions: 554675 (389245/s)
temporary memory allocations: 101574 (71280/s)
peak heap memory consumption: 28.46MB
peak RSS (including heaptrack overhead): 116.26MB
total memory leaked: 269.10KB
```

After:
```
calls to allocation functions: 512465 (345559/s)
temporary memory allocations: 98832 (66643/s)
peak heap memory consumption: 22.54MB
peak RSS (including heaptrack overhead): 106.58MB
total memory leaked: 269.10KB
```

Difference:
```
calls to allocation functions: -42210 (-727758/s)
temporary memory allocations: -2742 (-47275/s)
peak heap memory consumption: -5.92MB
peak RSS (including heaptrack overhead): 0B
total memory leaked: 0B
```