ABataev added a comment. In D71225#1776113 <https://reviews.llvm.org/D71225#1776113>, @jdoerfert wrote:
> In D71225#1776105 <https://reviews.llvm.org/D71225#1776105>, @cchen wrote: > > > Oops, accidentally remove my own comment. I'm not sure why `iarr[foo(), > > foo(), 0]` violate the rule since it will be evaluated as `iarr[0]`, and > > the counter `foo()` modified is also in the same location for both left > > hand side and right hand side. > > > It's not a violation but it taps into the unspecified behavior, which in > combination with side effects seems to be worth a warning. > > So my reasoning is: > > //x := `iarr[foo(), foo(), 0]`// > > which is fine on its own. Using it in the atomic update of the form, > > // x = x + 1// > > also fine. > > However, the standard says the number of times //x// is evaluated is > unspecified. > Thus, transforming the above to > > // x += 1 // > > should be valid. So should be, > > // t = &x; *t = *t + 1 // > > and even > > // x = (x, x, x, x+1) // Agree, missed that he used commas instead of array expressions. Repository: rG LLVM Github Monorepo CHANGES SINCE LAST ACTION https://reviews.llvm.org/D71225/new/ https://reviews.llvm.org/D71225 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
