bruno added a comment. In http://reviews.llvm.org/D21700#470103, @rnk wrote:
> After writing r266366, we discovered that GCC accepts none of the code in > that test case, so we should consider turning -flax-vector-conversions off by > default. Makes sense, specially given the non obvious semantics; users shouldn't rely on this behavior by default without the knowledge of what's actually going on. ================ Comment at: test/Sema/vector-cast.c:65 @@ -59,1 +64,3 @@ + d = f2; + d = d + f2; } ---------------- rnk wrote: > Why should we allow this conversion? I don't see how <2 x float> and double > should be convertible. I'm not sure why we allow `f2 += d` above, but I think > of it as "widening" the type from scalar to vector. > > Would it be OK for your if we tightened our lax vector conversion checks to > just allow conversion from `<1 x T>` to `T`? The test case in the summary > seems like pretty reasonable code, even if GCC rejects. I misread the testcase, `<2 x float>` and `double` shouldn't be convertible indeed. Thanks for the catch. Allowing conversions from `<1 x T>` to `T` is enough for us, it also sounds more correct. http://reviews.llvm.org/D21700 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
