[Bug rtl-optimization/70398] New: [6 Regression] gcc.dg/vect/slp-multitypes-9.c FAILs with -fno-tree-loop-optimize -fno-tree-ter

["zsojka at seznam dot cz" <gcc-bugzilla at gcc dot gnu dot org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=70398

            Bug ID: 70398
           Summary: [6 Regression] gcc.dg/vect/slp-multitypes-9.c FAILs
                    with -fno-tree-loop-optimize -fno-tree-ter
           Product: gcc
           Version: 6.0
            Status: UNCONFIRMED
          Keywords: wrong-code
          Severity: normal
          Priority: P3
         Component: rtl-optimization
          Assignee: unassigned at gcc dot gnu.org
          Reporter: zsojka at seznam dot cz
  Target Milestone: ---
            Target: aarch64-unknown-linux-gnu

Created attachment 38079
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=38079&action=edit
reduced testcase

Output (qemu userspace emulation):
$ aarch64-unknown-linux-gnu gcc -O -fno-tree-loop-optimize -fno-tree-ter
-static testcase.c
$ ./a.out 
qemu: uncaught target signal 11 (Segmentation fault) - core dumped
Segmentation fault

Crash is at:
Dump of assembler code for function main:
   0x0000000000400ac8 <+0>:     mov     w2, #0x0                        // #0
   0x0000000000400acc <+4>:     adrp    x4, 0x490000
   0x0000000000400ad0 <+8>:     add     x4, x4, #0x10
   0x0000000000400ad4 <+12>:    adrp    x3, 0x493000 <archive_stat+112>
   0x0000000000400ad8 <+16>:    add     x3, x3, #0x530
   0x0000000000400adc <+20>:    lsl     w0, w2, #1
=> 0x0000000000400ae0 <+24>:    ldrb    w1, [x4,x5]
   0x0000000000400ae4 <+28>:    add     w1, w1, #0x1
   0x0000000000400ae8 <+32>:    strb    w1, [x3,w0,sxtw]

x5 is never initialised.

.ira has:
(insn 8 7 11 3 (set (reg:SI 74 [ _5 ])
        (ashift:SI (reg/v:SI 82 [ i ])
            (const_int 1 [0x1]))) testcase.c:13 636
{*aarch64_ashl_sisd_or_int_si3}
     (nil))
(note 11 8 12 3 NOTE_INSN_DELETED)
(insn 12 11 13 3 (set (reg:SI 75 [ _6 ])
        (mem:SI (plus:DI (sign_extract:DI (mult:DI (subreg:DI (reg:SI 74 [ _5
]) 0)
                        (const_int 4 [0x4]))
                    (const_int 34 [0x22])
                    (const_int 0 [0]))
                (reg/f:DI 102)) [1 in S4 A64])) testcase.c:13 49
{*movsi_aarch64}
     (expr_list:REG_EQUIV (mem:SI (plus:DI (sign_extract:DI (mult:DI (subreg:DI
(reg:SI 74 [ _5 ]) 0)
                        (const_int 4 [0x4]))
                    (const_int 34 [0x22])
                    (const_int 0 [0]))
                (reg/f:DI 102)) [1 in S4 A64])
        (nil)))
(insn 13 12 14 3 (set (reg:SI 76 [ _7 ])
        (zero_extend:SI (subreg:QI (reg:SI 75 [ _6 ]) 0))) testcase.c:13 90
{*zero_extendqisi2_aarch64}
     (expr_list:REG_DEAD (reg:SI 75 [ _6 ])
        (nil)))

but .reload has:
(insn 8 7 11 3 (set (reg:SI 0 x0 [orig:74 _5 ] [74])
        (ashift:SI (reg/v:SI 2 x2 [orig:82 i ] [82])
            (const_int 1 [0x1]))) testcase.c:13 636
{*aarch64_ashl_sisd_or_int_si3}
     (nil))
(note 11 8 12 3 NOTE_INSN_DELETED)
(note 12 11 13 3 NOTE_INSN_DELETED)
(insn 13 12 14 3 (set (reg:SI 1 x1 [orig:76 _7 ] [76])
        (zero_extend:SI (mem:QI (plus:DI (reg/f:DI 4 x4 [102])
                    (reg:DI 5 x5 [139])) [1 in S1 A64]))) testcase.c:13 90
{*zero_extendqisi2_aarch64}
     (nil))


.ira might be correct, but .reload is wrong. Insn 12 is deleted without any
replacement (and it turns out, the same happens with insn 25)


@@ -23,12 +23,14 @@
 .L2:
        .loc 1 13 0 is_stmt 0 discriminator 3
        lsl     w0, w2, 1
-       ldrb    w1, [x4, x5]
+       lsl     w5, w0, 2
+       ldrb    w1, [x4, w5, sxtw]
        add     w1, w1, 1
        strb    w1, [x3, w0, sxtw]
        .loc 1 14 0 is_stmt 1 discriminator 3
        add     w0, w0, 1
-       ldrb    w1, [x4, x6]
+       lsl     w6, w0, 2
+       ldrb    w1, [x4, w6, sxtw]
        add     w1, w1, 2
        strb    w1, [x3, w0, sxtw]
        .loc 1 11 0 discriminator 3


fixes the asm.


Tested revisions:
trunk r234405 - FAIL
5-branch r234375 - OK