sepavloff added inline comments.
================
Comment at: clang/lib/AST/Interp/Floating.h:54-62
+ explicit operator int8_t() const { return toAPSInt().getExtValue(); }
+ explicit operator uint8_t() const { return toAPSInt().getExtValue(); }
+ explicit operator int16_t() const { return toAPSInt().getExtValue(); }
+ explicit operator uint16_t() const { return toAPSInt().getExtValue(); }
+ explicit operator int32_t() const { return toAPSInt().getExtValue(); }
+ explicit operator uint32_t() const { return toAPSInt().getExtValue(); }
+ explicit operator int64_t() const { return toAPSInt().getExtValue(); }
----------------
tbaeder wrote:
> sepavloff wrote:
> > tbaeder wrote:
> > > sepavloff wrote:
> > > > Conversions to integers are bitcasts+truncation but the conversion to
> > > > bool is different. What semantics have these operations?
> > > They are basically used for casting. I didn't mean to make the bool
> > > implementation different, just seemed to make sense to me to do it this
> > > way.
> > If they are used for casting, they need to preserve value, that is
> > conversion float->int32 should transform 1.0->0x00000001. The method
> > `toAPSInt` uses bitcast, so it converts 1.0->0x3f800000.
> > `APFloat::convertToInteger` should be used to make value-preverving
> > conversion but it requires knowledge of rounding mode.
> That's good to know, thanks. I've already used `TowardZero` in
> `Floating::toSemantics()`, but that was more a guess.
>
> Is the rounding mode I'm supposed to use simply
> `LangOptions::getDefaultRoundingMode()`?
Rounding mode is stored in AST node, a call to `Expr::getFPFeaturesInEffect`
may be used to extract various FP features in the form of `FPOptions`.
`LangOptions::getDefaultRoundingMode()` returns the default rounding mode,
which may be changed using `#pragma STDC FENV_ROUND`.
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D134859/new/
https://reviews.llvm.org/D134859
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