In case of nested loops if we encounter an inner loop block it is possible that the analysis will be stopped there and we lost coverage even with 'conservative-loop-widen' option.
So in these cases we could retry to analyze the outer loop with a widened state which could result better coverage. (eg. see nested loop testcases)
Note: This revision contains copy-pasted codelines from LoopUnrolling.cpp. The main point is the idea here and in case it is accepted, then merging the two files (LoopUnrolling.cpp, LoopWidening.cpp) into one (eg. LoopModelling.cpp) would be worth considering.