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* [Bug middle-end/33662]  New: [4.3 Regression] Wrong register allocation on SH
@ 2007-10-05  1:54 kkojima at gcc dot gnu dot org
  2007-10-08  2:23 ` [Bug middle-end/33662] " kkojima at gcc dot gnu dot org
                   ` (7 more replies)
  0 siblings, 8 replies; 9+ messages in thread
From: kkojima at gcc dot gnu dot org @ 2007-10-05  1:54 UTC (permalink / raw)
  To: gcc-bugs

Several libffi testcases and gcc.c-torture/execute/pr23135.c
fail with the execution error for sh4-unknown-linux-gnu after
the patch:

r128957 | zadeck | 2007-10-02 22:10:07 +0900 (Tue, 02 Oct 2007) | 70 lines

A reduced testcase is

typedef struct A {
  unsigned long long a;
  unsigned char b;
} A;

typedef struct B {
  struct A x;
  unsigned char y;
} B;

B B_fn(struct A b0, struct B b1)
{
  struct B result;

  result.x.a = b0.a + b1.x.a;
  result.x.b = b0.b + b1.x.b + b1.y;
  result.y = b0.b + b1.x.b;

  printf("%d %d %d %d %d: %d %d %d\n", (int)b0.a, b0.b,
         (int)b1.x.a, b1.x.b, b1.y,
         (int)result.x.a, result.x.b, result.y);

  return result;
}

which is compiled to

B_fn:
        mov.l   r8,@-r15
        clrt
        mov.l   r9,@-r15
        mov.l   r10,@-r15
        mov.l   r11,@-r15
        mov.l   r12,@-r15
        mov.l   r13,@-r15
        mov     r2,r13
        mov.l   r14,@-r15
        sts.l   pr,@-r15
        add     #-28,r15
        mov     r15,r14
        mov     r14,r1
        add     #60,r1
        mov.l   @r1+,r7
        mov.l   @r1+,r8
        add     #-20,r15
        mov.b   @r1,r0
        extu.b  r6,r8

with -O2 -ml -m4 on sh-elf.  The last extu.b instruction
clobbers r8 whose content was loaded from a memory with
"mov.l  @r1+,r8".

The corresponding .lreg dump is:

(insn:HI 20 68 23 3 str3.c:12 (set (reg:DI 164 [ b1$x$a ])
        (mem/s/c:DI (post_inc:SI (reg/f:SI 178)) [5 b1.x.a+0 S8 A32])) 186
{*movdi_i} (expr_list:REG_INC (reg/f:SI 178)
        (nil)))

(insn:HI 23 20 19 3 str3.c:12 (set (reg:QI 179 [ b1.x.b ])
        (mem/s/c:QI (reg/f:SI 178) [0 b1.x.b+0 S1 A32])) 182 {movqi_i}
(expr_list:REG_DEAD (reg/f:SI 178)
        (nil)))

(insn:HI 19 23 76 3 str3.c:12 (set (reg:SI 165 [ b0$b ])
        (zero_extend:SI (reg:QI 6 r6))) 153 {*zero_extendqisi2_compact} (nil))

and the .greg dump is:

(insn:HI 20 68 23 2 str3.c:12 (set (reg:DI 7 r7 [orig:164 b1$x$a ] [164])
        (mem/s/c:DI (post_inc:SI (reg/f:SI 1 r1 [178])) [5 b1.x.a+0 S8 A32]))
186 {*movdi_i} (expr_list:REG_INC (reg/f:SI 1 r1 [178])
        (nil)))

(insn:HI 23 20 19 2 str3.c:12 (set (reg:QI 0 r0 [orig:179 b1.x.b ] [179])
        (mem/s/c:QI (reg/f:SI 1 r1 [178]) [0 b1.x.b+0 S1 A32])) 182 {movqi_i}
(nil))

(insn:HI 19 23 79 2 str3.c:12 (set (reg:SI 8 r8 [orig:165 b0$b ] [165])
        (zero_extend:SI (reg:QI 6 r6))) 153 {*zero_extendqisi2_compact} (nil))

It looks that the register allocater selects r8 for pseudo
165, but r8 is already allocated as a part of the register
pair r7..r8 which is allocated for pseudo 164.


-- 
           Summary: [4.3 Regression] Wrong register allocation on SH
           Product: gcc
           Version: 4.3.0
            Status: UNCONFIRMED
          Keywords: wrong-code
          Severity: normal
          Priority: P3
         Component: middle-end
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: kkojima at gcc dot gnu dot org
GCC target triplet: sh-elf


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=33662


^ permalink raw reply	[flat|nested] 9+ messages in thread
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Thread overview: 9+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2007-10-05  1:54 [Bug middle-end/33662] New: [4.3 Regression] Wrong register allocation on SH kkojima at gcc dot gnu dot org
2007-10-08  2:23 ` [Bug middle-end/33662] " kkojima at gcc dot gnu dot org
2007-10-08  3:53 ` zadeck at naturalbridge dot com
2007-10-10 13:28 ` kkojima at gcc dot gnu dot org
2007-10-10 13:33 ` zadeck at naturalbridge dot com
2007-10-11  0:52 ` spark at gcc dot gnu dot org
2007-10-11  3:07 ` spark at gcc dot gnu dot org
2007-10-11 21:51 ` zadeck at naturalbridge dot com
2007-10-12  2:06 ` kkojima at gcc dot gnu dot org

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