https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103882
--- Comment #6 from Jose Silva <krystalgamer at protonmail dot com> --- Yes, noipa does help. (In reply to Andrew Pinski from comment #3) > Oh that is because there is some IPA Register allocation going on. Anyways > this is still not a bug. You need to mark a0 as a clobber in the inline-asm > to let GCC know that a0 is touched. As I said I simplified the example, the original code had a syscall which I have no idea which registers will be clobbered. Before upgrading compilers I was using GCC 3.2 which produces the following code with `-nostdlib -Os`: ``` a0020060 <test>: a0020060: 27bdfff0 addiu sp,sp,-16 a0020064: ffb00000 sd s0,0(sp) a0020068: ffbf0008 sd ra,8(sp) a002006c: 0c008016 jal a0020058 <fail> a0020070: 0080802d move s0,a0 a0020074: 0200202d move a0,s0 a0020078: dfbf0008 ld ra,8(sp) a002007c: dfb00000 ld s0,0(sp) a0020080: 08008012 j a0020048 <is_first_char_a> a0020084: 27bd0010 addiu sp,sp,16 ``` I'm quite confused on why you say "Anyways this is still not a bug". IPA RA is making assumptions on procedures where it does not have enough information to do so, i.e functions with asm statements. It is disabled when a function pointer is used, why shouldn't it be for when a function with ASM statement is encountered? The code inside the `fail()` function is valid and does not break the ABI, GCC does not have enough information to perform IPA RA but does so(wrongly), to me that's a bug.
