[Bug target/68910] New: SPARC/cypress: Poor code generation, huge stack frame

[sebastian.huber@embedded-brains.de]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=68910

            Bug ID: 68910
           Summary: SPARC/cypress: Poor code generation, huge stack frame
           Product: gcc
           Version: 6.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: target
          Assignee: unassigned at gcc dot gnu.org
          Reporter: sebastian.huber@embedded-brains.de
  Target Milestone: ---

Created attachment 37036
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=37036&action=edit
Test case.

The code for the SHA512_Transform() function is very poor for the SPARC cypress
target.

sparc-rtems4.12-gcc -c -O2 sha512c.i -mcpu=cypress

sha512c.o:     file format elf32-sparc


Disassembly of section .text:

00000000 <SHA512_Transform>:
       0:       9d e3 b0 58     save  %sp, -4008, %sp
       4:       94 10 20 80     mov  0x80, %o2
       8:       92 10 00 19     mov  %i1, %o1
       c:       90 07 bd 80     add  %fp, -640, %o0
[...]
     10c:       40 00 00 00     call  10c <SHA512_Transform+0x10c>
     110:       90 07 bd 40     add  %fp, -704, %o0
     114:       c0 27 bd 20     clr  [ %fp + -736 ]
     118:       c0 27 bd 24     clr  [ %fp + -732 ]
     11c:       c0 27 bd 10     clr  [ %fp + -752 ]
     120:       c0 27 bd 14     clr  [ %fp + -748 ]
     124:       c0 27 bd 08     clr  [ %fp + -760 ]
     128:       c0 27 bd 0c     clr  [ %fp + -756 ]
     12c:       c0 27 bd 00     clr  [ %fp + -768 ]
     130:       c0 27 bd 04     clr  [ %fp + -764 ]
     134:       c0 27 bc f8     clr  [ %fp + -776 ]
     138:       c0 27 bc fc     clr  [ %fp + -772 ]
[...]

Compared to v8:

sparc-rtems4.12-gcc -c -O2 sha512c.i -mcpu=v8

00000000 <SHA512_Transform>:
       0:       9d e3 bc b8     save  %sp, -840, %sp
       4:       94 10 20 80     mov  0x80, %o2
       8:       92 10 00 19     mov  %i1, %o1
       c:       90 07 bd 80     add  %fp, -640, %o0
      10:       40 00 00 00     call  10 <SHA512_Transform+0x10>
      14:       f0 27 a0 44     st  %i0, [ %fp + 0x44 ]
[...]

No massive clr instructions.