https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103465
--- Comment #5 from Martin Liška <marxin at gcc dot gnu.org> --- > However, still talking about the current master only, I see a difference > with -O3, when I try on the repro example from Bug 103274 and -O3: > > x86_64-w64-mingw32-gcc -c -S -O3 -fno-reorder-blocks-and-partition a.c -o > nropt.s > > x86_64-w64-mingw32-gcc -c -S -O3 -freorder-blocks-and-partition a.c -o ropt.s > x86_64-w64-mingw32-gcc -c -S -O3 a.c -o noopt.s > > All of these assembler files are different (and from my non-expert reading, > noopt.s uses the optimization and does have the invalid unwind information > as reported in Bug 103274). Is the optimization correctly dropped also with > -O3 only? Hmmm, I've just tested the same with the locally built cross-compiler: ~/Programming/gcc/configure --enable-languages=c,c++ --prefix=/home/marxin/bin/gcc --disable-multilib --enable-host-shared --disable-libsanitizer --enable-valgrind-annotations --disable-bootstrap --target=x86_64-w64-mingw32 and it works fine, all 3 assembly files are identical. cat 1.s .file "pr103274.c" .text .section .rdata,"dr" .LC0: .ascii "factor\0" .text .p2align 4 .globl _Z5dummyP7SEXPREC .def _Z5dummyP7SEXPREC; .scl 2; .type 32; .endef .seh_proc _Z5dummyP7SEXPREC _Z5dummyP7SEXPREC: .LFB2: pushq %r13 .seh_pushreg %r13 pushq %r12 .seh_pushreg %r12 pushq %rbp .seh_pushreg %rbp pushq %rdi .seh_pushreg %rdi pushq %rsi .seh_pushreg %rsi pushq %rbx .seh_pushreg %rbx subq $40, %rsp .seh_stackalloc 40 .seh_endprologue movq %rcx, %r12 call _Z11mypredicateP7SEXPREC testl %eax, %eax jne .L21 .L2: movq .refptr.R_NilValue(%rip), %rax movq (%rax), %rax addq $40, %rsp popq %rbx popq %rsi popq %rdi popq %rbp popq %r12 popq %r13 ret .p2align 4,,10 .p2align 3 .L21: movq %r12, %rcx call _Z11mygetattribP7SEXPREC movq %rax, %rcx movq %rax, %r13 call _Z8mylengthP7SEXPREC movl %eax, %ebp testl %eax, %eax jle .L2 movl %eax, %r12d movl $1, %esi leaq .LC0(%rip), %rdi jmp .L6 .p2align 4,,10 .p2align 3 .L8: movq %rax, %rsi .L6: movzbl 0(%r13), %ebx andl $1, %ebx je .L3 leal -1(%rsi), %edx movq %r13, %rcx call _Z11myaltstringP7SEXPRECi movq %rdi, %rdx movq %rax, %rcx addq $8, %rcx call _Z6strcmpPKcS0_ testl %eax, %eax je .L5 .L22: cmpq %r12, %rsi je .L2 leaq 1(%rsi), %rax testb %bl, %bl jne .L8 movslq %esi, %rsi .L7: movq 8(%r13,%rsi,8), %rax movq %rdi, %rdx leaq 8(%rax), %rcx call _Z6strcmpPKcS0_ testl %eax, %eax je .L5 addq $1, %rsi cmpl %esi, %ebp jg .L7 jmp .L2 .p2align 4,,10 .p2align 3 .L3: movq 0(%r13,%rsi,8), %rcx movq %rdi, %rdx addq $8, %rcx call _Z6strcmpPKcS0_ testl %eax, %eax jne .L22 .L5: call _Z11myerrorcallv nop .seh_endproc .ident "GCC: (GNU) 12.0.0 20211209 (experimental)" .def _Z11mypredicateP7SEXPREC; .scl 2; .type 32; .endef .def _Z11mygetattribP7SEXPREC; .scl 2; .type 32; .endef .def _Z8mylengthP7SEXPREC; .scl 2; .type 32; .endef .def _Z11myaltstringP7SEXPRECi; .scl 2; .type 32; .endef .def _Z6strcmpPKcS0_; .scl 2; .type 32; .endef .def _Z11myerrorcallv; .scl 2; .type 32; .endef .section .rdata$.refptr.R_NilValue, "dr" .globl .refptr.R_NilValue .linkonce discard .refptr.R_NilValue: .quad R_NilValue