On Mon, Jul 4, 2011 at 11:38 PM, Peter Maydell <peter.maydell@xxxxxxxxxx> wrote: > On 4 July 2011 23:00, Raghavendra D Prabhu <raghu.prabhu13@xxxxxxxxx> wrote: >> This is to avoid gcc optimizating out the comparison in assert, >> due to assumption of signed overflow being undefined by default (-Werror=strict-overflow). > >>--- a/Makefile.hw >>+++ b/Makefile.hw >>@@ -9,7 +9,7 @@ include $(SRC_PATH)/rules.mak >> >> $(call set-vpath, $(SRC_PATH):$(SRC_PATH)/hw) >> >> -QEMU_CFLAGS+=-I.. -I$(SRC_PATH)/fpu >> +QEMU_CFLAGS+=-I.. -I$(SRC_PATH)/fpu -fno-strict-overflow > > Can you give a more detailed description of the problem this is trying > to solve? I think it would be nicer if we could remove the assumptions > about signed overflows instead, if that's practical. > > (Also, if we do want to add this compiler flag then it ought to be > done in configure I think, as we do for -fno-strict-aliasing.) "a correct C/C++ program must never generate signed overflow when computing an expression. It also means that a compiler may assume that a program will never generated signed overflow." http://www.airs.com/blog/archives/120 Stefan -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
