• d-bugmail puremagic.com (31/31) Oct 25 2018 https://issues.dlang.org/show_bug.cgi?id=19333

d-bugmail puremagic.com writes:

https://issues.dlang.org/show_bug.cgi?id=19333

          Issue ID: 19333
           Summary: Add float, double and real overloads over volatileLoad
                    and volatileStore
           Product: D
           Version: D2
          Hardware: All
                OS: All
            Status: NEW
          Severity: enhancement
          Priority: P1
         Component: dmd
          Assignee: nobody puremagic.com
          Reporter: ibuclaw gdcproject.org

These might be useful for the buggy std.math tests where clever compilers don't
raise FE flags if it is able to const-fold the value at compile time - such as
GDC or LDC

For example, the following test returns false for `ieeeFlags.inexact` with
optimizations on.

```
() { x = 1; x += 0.1; },
() => ieeeFlags.inexact
```

So we would benefit from instead writing it as:

```
() { volatileStore(&x, 1); volatileStore(&x, x + 0.1); }
() => ieeeFlags.inexact
```

Which should be guaranteed to be true if the compiler adheres to correct
volatile semantics.

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