Commit Graph

4 Commits

Author SHA1 Message Date
Johannes Doerfert 72adda1740 [Attributor] Handle `null` differently in capture and alias logic
Summary:
`null` in the default address space (=AS 0) cannot be captured nor can
it alias anything. We make this clear now as it can be important for
callbacks and other cases later on. In addition, this patch improves the
debug output for noalias deduction.

Reviewers: sstefan1, uenoku

Subscribers: hiraditya, bollu, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D68624

llvm-svn: 374280
2019-10-10 05:33:21 +00:00
Hideto Ueno fb8218f252 [Attributor][Fix] Temporary fix for windows build bot failure
D65402 causes test failure related to attributor-max-iterations.
This commit removes attributor-max-iterations-verify for now.
I'll examine the factor and the flag should be reverted.

llvm-svn: 374086
2019-10-08 17:01:56 +00:00
Hideto Ueno 96e6ce4cd3 [Attributor][MustExec] Deduce dereferenceable and nonnull attribute using MustBeExecutedContextExplorer
Summary:
In D65186 and related patches, MustBeExecutedContextExplorer is introduced. This enables us to traverse instructions guaranteed to execute from function entry. If we can know the argument is used as `dereferenceable` or `nonnull` in these instructions, we can mark `dereferenceable` or `nonnull` in the argument definition:

1. Memory instruction (similar to D64258)
Trace memory instruction pointer operand. Currently, only inbounds GEPs are traced.
```
define i64* @f(i64* %a) {
entry:
  %add.ptr = getelementptr inbounds i64, i64* %a, i64 1
; (because of inbounds GEP we can know that %a is at least dereferenceable(16))
  store i64 1, i64* %add.ptr, align 8
  ret i64* %add.ptr ; dereferenceable 8 (because above instruction stores into it)
}
```

2. Propagation from callsite (similar to D27855)
If `deref` or `nonnull` are known in call site parameter attributes we can also say that argument also that attribute.

```
declare void @use3(i8* %x, i8* %y, i8* %z);
declare void @use3nonnull(i8* nonnull %x, i8* nonnull %y, i8* nonnull %z);

define void @parent1(i8* %a, i8* %b, i8* %c) {
  call void @use3nonnull(i8* %b, i8* %c, i8* %a)
; Above instruction is always executed so we can say that@parent1(i8* nonnnull %a, i8* nonnull %b, i8* nonnull %c)
  call void @use3(i8* %c, i8* %a, i8* %b)
  ret void
}
```

Reviewers: jdoerfert, sstefan1, spatel, reames

Reviewed By: jdoerfert

Subscribers: xbolva00, hiraditya, jfb, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D65402

llvm-svn: 374063
2019-10-08 15:25:56 +00:00
Johannes Doerfert 661db04b98 [Attributor] Use abstract call sites for call site callback
Summary:
When we iterate over uses of functions and expect them to be call sites,
we now use abstract call sites to allow callback calls.

Reviewers: sstefan1, uenoku

Subscribers: hiraditya, bollu, hfinkel, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D67871

llvm-svn: 373985
2019-10-07 23:14:58 +00:00