------- Comment #2 from pinskia at gcc dot gnu dot org 2006-06-09 06:20 ------- Here is the RTL we get on PPC: (insn 6 9 7 2 (set (reg/v:SI 120 [ x ]) (reg:SI 3 r3 [ x ])) 327 {*movsi_internal1} (nil) (expr_list:REG_DEAD (reg:SI 3 r3 [ x ]) (expr_list:REG_EQUIV (mem/c/i:SI (plus:SI (reg/f:SI 67 ap) (const_int 24 [0x18])) [4 x+0 S4 A32]) (nil)))) ...
(insn 13 12 14 2 (set (reg:SI 124) (lshiftrt:SI (reg/v:SI 120 [ x ]) (const_int 2 [0x2]))) 195 {lshrsi3_no_power} (insn_list:REG_DEP_TRUE 6 (nil)) (expr_list:REG_DEAD (reg/v:SI 120 [ x ]) (nil))) (insn 14 13 15 2 (parallel [ (set (reg:SI 125) (and:SI (reg:SI 124) (const_int 3 [0x3]))) (clobber (scratch:CC)) ]) 146 {andsi3} (insn_list:REG_DEP_TRUE 13 (nil)) (expr_list:REG_DEAD (reg:SI 124) (expr_list:REG_UNUSED (scratch:CC) (nil)))) (insn 15 14 17 2 (set (reg:SI 126) (ashift:SI (reg:SI 125) (const_int 2 [0x2]))) 189 {ashlsi3_no_power} (insn_list:REG_DEP_TRUE 14 (nil)) (expr_list:REG_DEAD (reg:SI 125) (nil))) Which gets reduced to: (insn 15 14 17 2 (parallel [ (set (reg:SI 126) (and:SI (reg:SI 3 r3 [ x ]) (const_int 12 [0xc]))) (clobber (scratch:CC)) ]) 146 {andsi3} (nil) (expr_list:REG_UNUSED (scratch:CC) (expr_list:REG_DEAD (reg:SI 3 r3 [ x ]) (nil)))) -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=27971