llvm dev - Jun 2015 - [LLVMdev] APInt with uint64_t comparison

Hi LLVM,

I have painfully found out that APInt comparison with uint64_t using
methods like .ult() is done with the precision of the APInt instance. The
uint64_t argument is usually silently truncated then. E.g. APInt{8,
1}.ult(256) is false.

I propose to change that and do the comparison with 64 bit precision. I
think it is much more useful as APInts representing the value of a constant
is often compared with the size of a type.

There are no unit tests for APInt comparisons. I've changed the
implementation locally and haven't spot any regressions.

If the proposal is accepted I will send the patch for review and do
self-hosted testing.

Cheers,
- Paweł
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On Tue, Jun 23, 2015 at 1:27 PM Paweł Bylica <chfast at gmail.com> wrote:
> Hi LLVM,
>
> I have painfully found out that APInt comparison with uint64_t using
> methods like .ult() is done with the precision of the APInt instance. The
> uint64_t argument is usually silently truncated then. E.g. APInt{8,
> 1}.ult(256) is false.
>
> I propose to change that and do the comparison with 64 bit precision. I
> think it is much more useful as APInts representing the value of a constant
> is often compared with the size of a type.
>
> There are no unit tests for APInt comparisons. I've changed the
> implementation locally and haven't spot any regressions.
>
I haven't found any issues in self-hosted check-all and test-suite.
Patch: http://reviews.llvm.org/D10655

If the proposal is accepted I will send the patch for review and
do
> self-hosted testing.
>
> Cheers,
> - Paweł
>
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