> On Nov 27, 2015, at 16:53, Rasmus Villemoes <linux@xxxxxxxxxxxxxxxxxx> wrote: > > Hi, > > It seems that gcc happily compiles > > for (i = 0; i < 1000000000; ++i) ; > > into simply > > i = 1000000000; > > (which is then usually eliminated as a dead store). At least at -O2, and > when i is not declared volatile. So it would seem that the loops at > > arch/mips/pci/pci-rt2880.c:235 > arch/mips/pmcs-msp71xx/msp_setup.c:80 > arch/mips/sni/reset.c:35 > > actually don't do anything. (In the middle one, i is 'register', but > that doesn't change anything.) Is mips compiled with some special flags > that would make gcc actually emit code for the above? > you can try to declare i as volatile int i; may gcc will not optimize it . Thanks
