On Sun, Nov 18, 2018 at 11:02:19PM +0800, Yafang Shao wrote: > On Sun, Nov 18, 2018 at 8:13 PM Matthew Wilcox <willy@xxxxxxxxxxxxx> wrote: > > Did you check the before/after code generation with this patch applied? > > Yes, I did. > My oompiler is gcc-4.8.5, a litte old, and with CONFIG_CC_OPTIMIZE_FOR_SIZE on. > > with gcc 8.2.0, I see no difference, indicating that the compiler already > > makes this optimisation. > > Could pls. try set CONFIG_CC_OPTIMIZE_FOR_SIZE on and then compare them again ? Actually it was already on: # CONFIG_CC_OPTIMIZE_FOR_PERFORMANCE is not set CONFIG_CC_OPTIMIZE_FOR_SIZE=y I happened to build it in my build-tiny output tree.
