On 07/03/2018 12:28 PM, Qing Zhao wrote: > >>> >>>> >>>> In order to collect complete information on all the inlining >>>> transformation that GCC applies on a given program, >>>> I searched online, and found that the option -fopt-info-inline might be >>>> the right option to use: >>>> >>>> https://gcc.gnu.org/onlinedocs/gcc/Developer-Options.html >>>> <https://gcc.gnu.org/onlinedocs/gcc/Developer-Options.html> >>>> <https://gcc.gnu.org/onlinedocs/gcc/Developer-Options.html >>>> <https://gcc.gnu.org/onlinedocs/gcc/Developer-Options.html>> >>>> <https://gcc.gnu.org/onlinedocs/gcc/Developer-Options.html >>>> <https://gcc.gnu.org/onlinedocs/gcc/Developer-Options.html>> >>>> >>>> in which, it mentioned: >>>> >>>> "As another example, >>>> gcc -O3 -fopt-info-inline-optimized-missed=inline.txt >>>> outputs information about missed optimizations as well as optimized >>>> locations from all the inlining passes into inline.txt. >>>> >>>> “ >>>> >>>> Then I checked a very small testcase with GCC9 as following: >>>> >>>> [qinzhao@localhost inline_report]$ cat inline_1.c >>>> static int foo (int a) >>>> { >>>> return a + 10; >>>> } >>>> >>>> static int bar (int b) >>>> { >>>> return b - 20; >>>> } >>>> >>>> static int boo (int a, int b) >>>> { >>>> return foo (a) + bar (b); >>>> } >>>> >>>> extern int v_a, v_b; >>>> extern int result; >>>> >>>> int compute () >>>> { >>>> result = boo (v_a, v_b); >>>> return result; >>>> } >>>> >>>> [qinzhao@localhost inline_report]$ /home/qinzhao/Install/latest/bin/gcc >>>> -O3 -fopt-info-inline-optimized-missed=inline.txt inline_1.c -S >>>> [qinzhao@localhost inline_report]$ ls -l inline.txt >>>> -rw-rw-r--. 1 qinzhao qinzhao 0 Jul 3 11:25 inline.txt >>>> [qinzhao@localhost inline_report]$ cat inline_1.s >>>> .file "inline_1.c" >>>> .text >>>> .p2align 4,,15 >>>> .globl compute >>>> .type compute, @function >>>> compute: >>>> .LFB3: >>>> .cfi_startproc >>>> movl v_a(%rip), %edx >>>> movl v_b(%rip), %eax >>>> leal -10(%rdx,%rax), %eax >>>> movl %eax, result(%rip) >>>> ret >>>> .cfi_endproc >>>> .LFE3: >>>> .size compute, .-compute >>>> .ident "GCC: (GNU) 9.0.0 20180702 (experimental)" >>>> .section .note.GNU-stack,"",@progbits >>>> >>>> From the above, we can see: >>>> 1. the call chains to —>“boo”->”foo”, “bar” in the routine “compute” >>>> are completely inlined into “compute”; >>>> 2. However, there is NO any inline information is dumped into >>>> “inline.txt”. >>>> >>>> >>>> So, My questions are: >>>> >>>> 1. Is the option -fopt-info-inline the right option to use to get the >>>> complete inlining transformation info from GCC? >>>> 2. is this a bug that the current -fopt-info-inline cannot dump >>>> anything for this testing case? >>> >>> I think the early inliner doesn't use opt-info yet. >> >> so, shall we add the opt-info support to early inliner? > > I just created the following PR to record this work: > > https://gcc.gnu.org/bugzilla/show_bug.cgi?id=86395 > <https://gcc.gnu.org/bugzilla/show_bug.cgi?id=86395> > > let me know if I missed anything. I'm hoping that the work David is doing WRT optimization information will be usable for the inliner as well. In fact, inlining and vectorization are the two use cases we identified internally as the first targets.
jeff
