+ linux-mtd, lkml, linux-sparse On Tue, Jul 22, 2014 at 10:28:13AM +0200, Boris BREZILLON wrote: > On Tue, 22 Jul 2014 11:41:08 +0800 kbuild test robot <fengguang.wu@xxxxxxxxx> wrote: > > tree: git://git.infradead.org/users/dedekind/l2-mtd.git master > > head: e4e069347030ab0fea7304d06704fb3b64e5fe40 > > commit: 974647ea8a13021a91d558df61d598bcabf73439 [25/29] mtd: nand: add ONFI timing mode to nand_timings converter > > reproduce: make C=1 CF=-D__CHECK_ENDIAN__ > > > > > > sparse warnings: (new ones prefixed by >>) > > > > >> drivers/mtd/nand/nand_timings.c:45:29: sparse: constant 250000000000 is so big it is long > > > > vim +45 drivers/mtd/nand/nand_timings.c > > > > 29 .tCLS_min = 50000, > > 30 .tCOH_min = 0, > > 31 .tCS_min = 70000, > > 32 .tDH_min = 20000, > > 33 .tDS_min = 40000, > > 34 .tFEAT_max = 1000000, > > 35 .tIR_min = 10000, > > 36 .tITC_max = 1000000, > > 37 .tRC_min = 100000, > > 38 .tREA_max = 40000, > > 39 .tREH_min = 30000, > > 40 .tRHOH_min = 0, > > 41 .tRHW_min = 200000, > > 42 .tRHZ_max = 200000, > > 43 .tRLOH_min = 0, > > 44 .tRP_min = 50000, > > > 45 .tRST_max = 250000000000, > > Appending ULL to the numerical constant should fix this warning. > > Do you want me to send a patch fixing this bug ? No bug here, AFAICT. I noted already that, although this may appear to overflow, it is in fact using standard behavior which says the constant will be promoted to the proper type. My comments: http://lists.infradead.org/pipermail/linux-arm-kernel/2014-April/252494.html Looking at ISO draft N1124 (this is approximately C11, the first PDF I had lying around), section 6.4.4.1 (statement 5): "The type of an integer constant is the first of the corresponding list in which its value can be represented." So I think this is a sparse false positive. Notably, Fengguang's build system also showed some complaints from an avr32 GCC toolchain. This is also a bug. Given that there are at least a few non-standards-compliant warnings out there (and possibly real toolchain bugs, if they're giving these warnings), perhaps it's prudent to patch this with a 'ULL' suffix, even though I prefer not to work around bugs in tools in principle. Brian -- To unsubscribe from this list: send the line "unsubscribe linux-sparse" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
