[Bug rtl-optimization/64317] [5 Regression] Ineffective allocation of PIC base register

["enkovich.gnu at gmail dot com" <gcc-bugzilla@gcc.gnu.org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64317

Ilya Enkovich <enkovich.gnu at gmail dot com> changed:

           What    |Removed                     |Added
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                 CC|                            |enkovich.gnu at gmail dot com

--- Comment #3 from Ilya Enkovich <enkovich.gnu at gmail dot com> ---
Created attachment 34675
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=34675&action=edit
Another reproducer

I found one more reproducer for the problem.  Generated code for multiple
'output' calls inlined into test':

..
.L5:
        movl    28(%esp), %edx               <-- load PIC reg
        movl    %edi, (%ecx)
        leal    (%ebx,%eax), %ecx
        cmpl    %ecx, %ebp
        movl    %ebx, out_pos@GOTOFF(%edx)
        movl    val3@GOTOFF(%edx), %edi
        jnb     .L6
        movl    28(%esp), %ebx              <-- have value in EDX
        movl    out@GOTOFF(%ebx), %ebx
        leal    (%ebx,%eax), %ecx
.L6:
        movl    28(%esp), %edx              <-- NOP
        movl    %edi, (%ebx)
        leal    (%ecx,%eax), %ebx
        cmpl    %ebx, %ebp
        movl    %ecx, out_pos@GOTOFF(%edx)
        movl    val4@GOTOFF(%edx), %edi
        jnb     .L7
        movl    28(%esp), %ecx             <-- have value in EDX
        movl    out@GOTOFF(%ecx), %ecx
        leal    (%ecx,%eax), %ebx
.L7:
        movl    28(%esp), %edx             <-- NOP
        movl    %edi, (%ecx)
...

BTW if I put __attribute__((noinline)) for crc32 function then mentioned code
becomes better and we don't have these two useless instructions in each
function instance.

Compilation string:

gcc -Ofast -funroll-loops -m32 -march=slm -fPIE test.i -S

Used compiler:

gcc version 5.0.0 20150203 (experimental) (GCC)