On 8/15/13 1:35 PM, Joern Rennecke wrote: > I see that gcc.dg/tree-ssa/ssa-pre-21.c fails for avr. > The computation of k + 1L is done as unsigned int (16 bit), > but later ++k is performed as unsigned long (32 bit), and thus > array[k+1] is not re-used. > > Is this to be considered a big in the optimizers for not > optimizing this, or in the testsuite for insisting that it > should be?
It's a but in the optimizer, the modified testcase should optimize well on i686. The issue is very likely that the frontend demotes array indices to sizetype. You may want to file a bugreport. Richard. > FWIW, equivalent behaviour can be seen natively on > i686-pc-linux-gnu by replacing "long" with "long long", > as shown in the attachment.
