[perl #131306] [SPESH] Incorrect results with `uint32` types after +> was made to handle large ints

[Zoffix Znet via RT]

On Sat, 13 May 2017 07:26:05 -0700, c...@zoffix.com wrote:
> Before ef29bb9f41aa5d[^1], the +> op special cased large shifts and
> large numbers. Now that special-casing was removed,
> it works fine in the first few runs, but then starts giving incorrect
> results (setting MVM_SPESH_DISABLE fixes the issue).
> 
> I couldn't repro it with *just* the `+>` op, but only in this
> combination:
> 
> <Zoffix_> c: ef29bb9f41aa5d sub rotr(uint32 $n, uint32 $b) { $n +> $b
> +| $n +< (32 - $b) }; say rotr 1652322944, 18; my $x; for ^1000 { $x =
> rotr 1652322944, 18 }; say $x
> <committable6> Zoffix_, ¦ef29bb9: «27071659120799␤27071659114496»
> <Zoffix_> c: ef29bb9f41aa5d~1 sub rotr(uint32 $n, uint32 $b) { $n +>
> $b +| $n +< (32 - $b) }; say rotr 1652322944, 18; my $x; for ^1000 {
> $x = rotr 1652322944, 18 }; say $x
> <committable6> Zoffix_, ¦ef29bb9f41aa5d~1:
> «27071659120799␤27071659120799»
> 
> [1] https://github.com/rakudo/rakudo/commit/ef29bb9f41aa5d


I added a temporary workaround[^1] as well as tests[^2] to cover this bug.

The issue still needs proper addressing as the workaround merely prevents 
inlining of +< and +> ops

[1] 
https://github.com/rakudo/rakudo/commit/2f22b701d4cf44fa43500edcc3450718fa7fd468
[2] https://github.com/perl6/roast/commit/c1d62112f3