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))))
