PredictableMemoryAccessOptimizations has become unmaintainable as-is.
RedundantLoadElimination does (almost) the same thing as PredictableMemoryAccessOptimizations.
It's not as powerful but good enough because PredictableMemoryAccessOptimizations is actually only needed for promoting integer values for mandatory constant propagation.
And most importantly: RedundantLoadElimination does not insert additional copies which was a big problem in PredictableMemoryAccessOptimizations.
Fixes rdar://142814676
Add a new mandatory BooleanLiteralFolding pass which constant folds conditional branches with boolean literals as operands.
```
%1 = integer_literal -1
%2 = apply %bool_init(%1) // Bool.init(_builtinBooleanLiteral:)
%3 = struct_extract %2, #Bool._value
cond_br %3, bb1, bb2
```
->
```
...
br bb1
```
This pass is intended to run before DefiniteInitialization, where mandatory inlining and constant folding didn't run, yet (which would perform this kind of optimization).
This optimization is required to let DefiniteInitialization handle boolean literals correctly.
For example in infinite loops:
```
init() {
while true { // DI need to know that there is no loop exit from this while-statement
if some_condition {
member_field = init_value
break
}
}
}
```
of OSLogMessage constant evaluable and remove @_transparent annotation
from the methods. Also, improve diagnostics in the OSLogOptimization
pass as now it rely on seeing the appendInterpolation/Literal calls.
1. builtin "int_expect", which makes the evaluator work on more
integer operations such as left/right shift (with traps) and
integer conversions.
2. builtin "_assertConfiguration", which enables the evaluator
to work with debug stdlib.
3. builtin "ptrtoint", which enables the evaluator to track
StaticString
4. _assertionFailure API, which enables the evaluator to report
stdlib assertion failures encountered during constant evaluation.
Also, enable attaching auxiliary data with the enum "UnknownReason"
and use it to improve diagnostics for UnknownSymbolicValues,
which represent failures during constant evaluation.
I also extracted out the recursion test into a FileCheck test so that we can
avoid having to do a -verify pattern match again the exact line where the
recursion limit was hit. This limit is noisy in the face of codegen changes
since we are IIRC counting instructions. Thus using -verify we can't pattern
match since the line can change easily.
This simplifies the IR and eliminates in a certain sense "constant information"
from the IR by allowing us to remove extract, nominal literal round trips.
NOTE: I had to modify the pound_assert test slightly on the location of a note
that it emits. The reason that I did this is that the test output is technically
correct. The instruction we are interpreting when we error is (after this
commit), a debug_value in the prelude of the function (and thus has the new
location). I am going to talk with Ravi and others on what to do with this.
The SIL generation for this builtin also changes: instead of generating the cond_fail instructions upfront, let the optimizer generate it, if the operand is a static string literal.
In worst case, if the second operand is not a static string literal, the Builtin.condfail is lowered at the end of the optimization pipeline with a default message: "unknown program error".
unknown symbolic values by renaming some diagnostics and
creating new unknown reasons for each type of failure that
can happen during constant evaluation.
Adds memory objects and addresses to the constant interpreter, and
teaches the constant interpreter to interpret various instructions that
deal with memory and addresses.
Implements a constant interpreter that can deal with basic integer operations.
Summary of the features that it includes:
* builtin integer values, and builtin integer insts
* struct and tuple values, and insts that construct and extract them (necessary to use stdlib integers)
* function referencing and application (necessary to call stdlib integer functions)
* error handling data structures and logic, for telling you why your value is not evaluatable
* metatype values (not necessary for integers, but it's only a few extra lines, so I thought it would be more trouble than it's worth to put them in a separate PR)
* conditional branches (ditto)
