In http://reviews.llvm.org/D10634#199554, @danielmarjamaki wrote:
> Here is a bigger log with more warnings. > https://drive.google.com/file/d/0BykPmWrCOxt2aGtRNTY4eXQ1OU0/view > > there are some cases where I don't think there should be a warning.. for > instance some compound assignments: > > args.c:990:9: warning: assigning negative value to unsigned variable loses > sign and may cause undesired runtime behavior > [clang-analyzer-alpha.core.LossOfSignAssign] > > tmp /= 10; > ^ > > read.c:4940:13: warning: assigning negative value to unsigned variable loses > sign and may cause undesired runtime behavior > [clang-analyzer-alpha.core.LossOfSignAssign] > > value >>= 7; > ^ > > > I am not an expert but it seems strange to me that clang seems to think that > 10 and 7 are negative. Can you investigate this? Here's a short test case that shows the problem: 1 void safe_mul(unsigned long x) { 2 unsigned long multiplier = 1000000000000000000; 3 while (x > 0) { 4 multiplier /= 10; 5 } 6 } I may be wrong here, but I believe that the warning is due to an overflow during constant folding of the initializer, which causes the RHS to be treated as negative. http://reviews.llvm.org/D10634 _______________________________________________ cfe-commits mailing list cfe-commits@cs.uiuc.edu http://lists.cs.uiuc.edu/mailman/listinfo/cfe-commits
