On 13/09/18 15:49, Paul Koning wrote:
It's ambiguous, because the last sentence of that paragraph says "addm3 is used if addptrm3 is not defined."
I didn't read that as ambiguous; I read it as addm3 is assumed to work fine when addptr is not defined.
I don't know of any change in this area. All I know is that pdp11 has adds that clobber CC and it doesn't define addptrm3, relying on that last sentence. I've tried LRA and for the most part it compiles successfully, I suppose I should verify the generated code based on the point you raised. If I really have to define addptr, I'm in trouble because save/restore CC is not easy on pdp11.
The code was added because we had a number of testcases that failed at runtime without it.
Admittedly, that was in a GCC 7 code-base, and I can't reproduce the failure with one of those test cases now (with addptr deleted), but possibly that's just noise.
Andrew
