[Bug tree-optimization/94956] Unable to remove impossible ffs() test for zero

[steinar+gcc at gunderson dot no]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94956

--- Comment #1 from Steinar H. Gunderson <steinar+gcc at gunderson dot no> ---
Sorry, truncated the assembler. GCC's is:

atum17:~> objdump --disassemble test.o                          

test.o:     file format elf64-x86-64


Disassembly of section .text:

0000000000000000 <foo>:
   0:   0f bc ff                bsf    %edi,%edi
   3:   b8 ff ff ff ff          mov    $0xffffffff,%eax
   8:   0f 45 c7                cmovne %edi,%eax
   b:   c3                      retq   
atum17:~>