https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64304
kugan at gcc dot gnu.org changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |kugan at gcc dot gnu.org
--- Comment #1 from kugan at gcc dot gnu.org ---
I haven't looked in detail but and:SI is gone during the combine stage. For
some reason, combine thinks it is OK to remove and:SI.
Here is the .213r.ud_dce and .214r.combine when it fails.
(note 5 0 2 2 [bb 2] NOTE_INSN_BASIC_BLOCK)
-(insn 2 5 3 2 (set (reg/v:SI 82 [ bit ])
- (reg:SI 0 x0 [ bit ])) bug.c:3 38 {*movsi_aarch64}
- (expr_list:REG_DEAD (reg:SI 0 x0 [ bit ])
- (nil)))
+(note 2 5 3 2 NOTE_INSN_DELETED)
(insn 3 2 4 2 (set (reg/v:SI 83 [ value ])
(zero_extend:SI (reg:QI 1 x1 [ value ]))) bug.c:3 76
{*zero_extendqisi2_aarch64}
(expr_list:REG_DEAD (reg:QI 1 x1 [ value ])
(nil)))
(note 4 3 7 2 NOTE_INSN_FUNCTION_BEG)
-(insn 7 4 8 2 (set (reg:SI 84 [ D.1492 ])
- (and:SI (reg/v:SI 82 [ bit ])
- (const_int 7 [0x7]))) bug.c:4 399 {andsi3}
- (expr_list:REG_DEAD (reg/v:SI 82 [ bit ])
- (nil)))
+(note 7 4 8 2 NOTE_INSN_DELETED)
(insn 8 7 9 2 (set (reg:SI 86)
(const_int 1 [0x1])) bug.c:4 38 {*movsi_aarch64}
(nil))
-(insn 9 8 10 2 (set (reg:SI 85 [ D.1492 ])
- (ashift:SI (reg:SI 86)
- (subreg:QI (reg:SI 84 [ D.1492 ]) 0))) bug.c:4 539
{*aarch64_ashl_sisd_or_int_si3}
- (expr_list:REG_DEAD (reg:SI 86)
- (expr_list:REG_DEAD (reg:SI 84 [ D.1492 ])
- (expr_list:REG_EQUAL (ashift:SI (const_int 1 [0x1])
- (subreg:QI (reg:SI 84 [ D.1492 ]) 0))
- (nil)))))
+(insn 9 8 10 2 (set (reg:QI 85 [ D.1492 ])
+ (ashift:QI (subreg:QI (reg:SI 86) 0)
+ (reg:QI 0 x0 [ bit ]))) bug.c:4 556 {*ashlqi3_insn}
+ (expr_list:REG_DEAD (reg:SI 0 x0 [ bit ])
+ (expr_list:REG_DEAD (reg:SI 86)
+ (nil))))
(insn 10 9 11 2 (set (reg/v:SI 76 [ mask ])
- (zero_extend:SI (subreg:QI (reg:SI 85 [ D.1492 ]) 0))) bug.c:4 76
{*zero_extendqisi2_aarch64}
- (expr_list:REG_DEAD (reg:SI 85 [ D.1492 ])
- (nil)))
-(insn 11 10 12 2 (set (reg:CC 66 cc)
- (compare:CC (reg/v:SI 83 [ value ])
- (const_int 0 [0]))) bug.c:5 330 {*cmpsi}
- (expr_list:REG_DEAD (reg/v:SI 83 [ value ])
+ (zero_extend:SI (reg:QI 85 [ D.1492 ]))) bug.c:4 76
{*zero_extendqisi2_aarch64}
+ (expr_list:REG_DEAD (reg:QI 85 [ D.1492 ])
(nil)))
.....
