Re: [PATCH v4 46/51] tcg/optimize: Use fold_xx_to_i for rem

[Richard Henderson]

On 10/27/21 1:42 PM, Luis Fernando Fujita Pires wrote:
> From: Richard Henderson <richard.henderson@linaro.org>
>
> >   static bool fold_remainder(OptContext *ctx, TCGOp *op)  {
> > -    return fold_const2(ctx, op);
> > +    if (fold_const2(ctx, op) ||
> > +        fold_xx_to_i(ctx, op, 1)) {
>
> Should this be fold_xx_to_i(ctx, op, 0)?

Oops.  I can only guess it's a cut-and-paste error.

> If arg[2] is 0, we would have different results than do_constant_folding(), but 
> not sure we care, since the result is documented as undefined.

At first I thought you meant a known 0, but you mean some unknown value which happens to 
be 0 at runtime.  Yes, we do get a different value, but yes, we don't care because undefined.


r~