[Bug tree-optimization/87287] Move signed (x % pow2) == 0 optimization to gimple

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=87287

--- Comment #1 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
With the to be posted patch, f1 and f3 remains the same, f2 and f4 improves:
-       movl    %edi, %eax
-       sarl    $31, %eax
-       shrl    $28, %eax
-       addl    %eax, %edi
+       xorl    %eax, %eax
        andl    $15, %edi
-       cmpl    %eax, %edi
        setne   %al
-       movzbl  %al, %eax
for f2 and
-       movl    %edi, %eax
-       sarl    $31, %eax
-       shrl    $28, %eax
-       addl    %eax, %edi
        andl    $15, %edi
-       cmpl    %eax, %edi
        je      .L9
for f4 at -O2.