On Sat, 16 Feb 2019, Jakub Jelinek wrote: > Hi! > > Both the C and C++ standard guarantee that the argc argument to main is > non-negative, the following patch sets (or adjusts) the corresponding > SSA_NAME_RANGE_INFO. While main is just one, with IPA VRP it can also > propagate etc. I had to change one testcase because it started optimizing > it better (the test has been folded away), so no sinking was done.
In C, unlike in C++, it's valid to call main recursively. I think the requirements on argc and argv must be understood to apply only to their values on entry to the initial call to main, not to any recursive calls. So I don't think this optimization is valid for C (in the absence of whole-program information that can prove the absence of any recursive calls). -- Joseph S. Myers jos...@codesourcery.com
