http://gcc.gnu.org/bugzilla/show_bug.cgi?id=60438
--- Comment #8 from linzj <manjian2006 at gmail dot com> --- Okay let me sum it up: at first the code looks like this call xxx: .cfa 92 float ops add sp 12 .cfa 80 And then split2 splits the float ops,then it looks like this call xxx: .cfa 92 push edx float ops2 add sp 4 ... add sp 12 .cfa 80 Note that the split code has a sp ops but no cfa notes. And then cfa feels that's ugly,it changes the code to call xxx : .cfa 92 push edx float ops2 ... add sp 16 .cfa 80 And then jump2 finds another branch also has an "add sp 16 .cfa 80",so the combination has occurred: call xxx :.cfa 92 push edx float ops2 ... label jump_from_other_branch ( (hasRelativeWidth || hasRelativeHeight) == true ) add sp 16 .cfa 80 then dwarf2cfi.c will first find the "add sp 16 .cfa 80" row has cfa 92 coming first,and then cfa 96.