#4213 Regression: blake2s fails for sm83

[Philipp Klaus Krause]

Recently, the test support/regression/test/blake2s.c fails for the test-ucgbz80 target. We should look into this soon, since this would be a regression vs. 4.6.0, so it should be fixed for SDCC 4.7.0.

[Gabriele Gorla]

The issue has been introduced in [r16036]
in SDCCcse.c static int isSignedOp (iCode *ic)

    case CAST:
        /* Casts from pointer types do not depend on the signedness
           of the source type. */
        return !IS_PTR (operandType (IC_RIGHT (ic)));
     case RIGHT_OP:
    case ARRAYINIT:
        return 1;

commenting the return statement make the test pass.