[Bug target/109259] New: rs6000:pass_analyze_swaps should preserve some rtx notes

[Bug target/109259] New: rs6000:pass_analyze_swaps should preserve some rtx notes

[linkw at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109259

            Bug ID: 109259
           Summary: rs6000:pass_analyze_swaps should preserve some rtx
                    notes
           Product: gcc
           Version: 13.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: target
          Assignee: unassigned at gcc dot gnu.org
          Reporter: linkw at gcc dot gnu.org
  Target Milestone: ---

When I was constructing test case for PR109069, I found that rs6000 specific
pass pass_analyze_swaps doesn't try to preserve REG_EQUAL notes for vector
constant. One typical case is:

#include <altivec.h>

vector signed int test2(vector signed int v1){
  vector signed int v = {-128, -1280, 1280, 128};
  return v+v1;
}

On LE, with -O2 -mcpu=power8, in 261r.swaps dump:

(insn 6 3 17 2 (set (reg/f:DI 121)
        (unspec:DI [
                (symbol_ref/u:DI ("*.LC0") [flags 0x82])
                (reg:DI 2 2)
            ] UNSPEC_TOCREL)) "tt.c":7:12 764 {*tocrefdi}
     (expr_list:REG_EQUAL (symbol_ref/u:DI ("*.LC0") [flags 0x82])
        (nil)))
(insn 17 6 18 2 (set (reg:V4SI 122)
        (mem/u/c:V4SI (and:DI (reg/f:DI 121)
                (const_int -16 [0xfffffffffffffff0])) [0  S16 A128]))
"tt.c":7:12 -1
     (nil))

while in 260r.dfinit dump, it has:

(note 3 2 6 2 NOTE_INSN_FUNCTION_BEG)
(insn 6 3 7 2 (set (reg/f:DI 121)
        (unspec:DI [
                (symbol_ref/u:DI ("*.LC0") [flags 0x82])
                (reg:DI 2 2)
            ] UNSPEC_TOCREL)) "tt.c":7:12 764 {*tocrefdi}
     (expr_list:REG_EQUAL (symbol_ref/u:DI ("*.LC0") [flags 0x82])
        (nil)))
(insn 7 6 8 2 (set (reg:V4SI 122)
        (vec_select:V4SI (mem/u/c:V4SI (reg/f:DI 121) [0  S16 A128])
            (parallel [
                    (const_int 2 [0x2])
                    (const_int 3 [0x3])
                    (const_int 0 [0])
                    (const_int 1 [0x1])
                ]))) "tt.c":7:12 1369 {*vsx_lxvd2x4_le_v4si}
     (nil))
(insn 8 7 9 2 (set (reg:V4SI 120)
        (vec_select:V4SI (reg:V4SI 122)
            (parallel [
                    (const_int 2 [0x2])
                    (const_int 3 [0x3])
                    (const_int 0 [0])
                    (const_int 1 [0x1])
                ]))) "tt.c":7:12 1358 {xxswapd_v4si}
     (expr_list:REG_EQUAL (const_vector:V4SI [
                (const_int -128 [0xffffffffffffff80])
                (const_int -1280 [0xfffffffffffffb00])
                (const_int 1280 [0x500])
                (const_int 128 [0x80])
            ])
        (nil)))

====

with -O2 -mcpu=power9, in 262r.cse1 rtl dump:

(insn 6 3 7 2 (set (reg/f:DI 121)
        (unspec:DI [
                (symbol_ref/u:DI ("*.LC0") [flags 0x82])
                (reg:DI 2 2)
            ] UNSPEC_TOCREL)) "tt.c":7:12 764 {*tocrefdi}
     (expr_list:REG_EQUAL (symbol_ref/u:DI ("*.LC0") [flags 0x82])
        (nil)))
(insn 7 6 8 2 (set (reg:V4SI 120)
        (mem/u/c:V4SI (reg/f:DI 121) [0  S16 A128])) "tt.c":7:12 1182
{vsx_movv4si_64bit}
     (expr_list:REG_DEAD (reg/f:DI 121)
        (expr_list:REG_EQUAL (const_vector:V4SI [
                    (const_int -128 [0xffffffffffffff80])
                    (const_int -1280 [0xfffffffffffffb00])
                    (const_int 1280 [0x500])
                    (const_int 128 [0x80])
                ])
            (nil))))

[Bug target/109259] rs6000:pass_analyze_swaps should preserve some rtx notes

[linkw at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109259

Kewen Lin <linkw at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Severity|normal                      |enhancement
                 CC|                            |bergner at gcc dot gnu.org,
                   |                            |segher at gcc dot gnu.org
             Target|                            |powerpc64le-linux-gnu