search for: lfb23

...movl $.L.str, (%esp) calll __isoc99_scanf movl 20(%esp), %eax * orl 24(%esp), %eax* addl $28, %esp retl As seen, optimization happened at IR level itself reflected in .s file. *GCC output for the same:* suyog at suyog-Inspiron-N5010:~$ gcc -S -O2 1.c main: .LFB23: .cfi_startproc pushl %ebp .cfi_def_cfa_offset 8 .cfi_offset 5, -8 movl %esp, %ebp .cfi_def_cfa_register 5 andl $-16, %esp subl $32, %esp leal 28(%esp), %eax movl %eax, 8(%esp) leal 24(%esp), %eax movl %eax, 4(%esp) movl...

...;>> >>>> As seen, optimization happened at IR level itself reflected in .s file. >>>> >>>> *GCC output for the same:* >>>> >>>> suyog at suyog-Inspiron-N5010:~$ gcc -S -O2 1.c >>>> >>>> main: >>>> .LFB23: >>>> .cfi_startproc >>>> pushl %ebp >>>> .cfi_def_cfa_offset 8 >>>> .cfi_offset 5, -8 >>>> movl %esp, %ebp >>>> .cfi_def_cfa_register 5 >>>> andl $-16, %esp >>>>...

Hi, All, Duncan, Rafael, David, Nick. This is regarding pattern matching in InstructionCombine pass. We use 'match' functions many times, but it doesn't do the pattern matching effectively. e.x. Lets take pattern : (A ^ B) | ((B ^ C) ^ A) -> (A ^ B) | C (B ^ A) | ((B ^ C) ^ A) -> (A ^ B) | C Both the patterns above are same, since ^ is commutative in Op0. But,

...gt;>> >>>> As seen, optimization happened at IR level itself reflected in .s file. >>>> >>>> GCC output for the same: >>>> >>>> suyog at suyog-Inspiron-N5010:~$ gcc -S -O2 1.c >>>> >>>> main: >>>> .LFB23: >>>> .cfi_startproc >>>> pushl %ebp >>>> .cfi_def_cfa_offset 8 >>>> .cfi_offset 5, -8 >>>> movl %esp, %ebp >>>> .cfi_def_cfa_register 5 >>>> andl $-16, %esp >>>>...