This PR was fixed earlier with a patch that was deemed safe for GCC 6 through the removal of splitters for zero extend and sign extend to HImode.
Now that trunk has opened for GCC 7 development, the following patch restores the splitters and fixes the bug in the more aggressive manner originally proposed: disallow patterns for extension to HImode by removing HImode from the iterator. The PowerPC architecture does not provide any instructions that directly operate on HImode, so it's better for GCC to operate on it as SUBREG except for loads and stores, as this patch accomplishes. Bootstrapped on powerpc-ibm-aix7.1.0.0. Thanks, David PR target/69810 * config/rs6000/rs6000.md (EXTQI): Don't allow extension to HImode. (zero_extendqi<mode>2_dot): Revert earlier conversion from define_insn_and_split to define_insn. (zero_extendqi<mode>2_dot2): Same. (extendqi<mode>2_dot): Same. (extendqi<mode>2_dot2): Same. Index: rs6000.md =================================================================== --- rs6000.md (revision 235573) +++ rs6000.md (working copy) @@ -322,7 +322,7 @@ (define_mode_iterator INT1 [QI HI SI (DI "TARGET_POWERPC64")]) ; Everything we can extend QImode to. -(define_mode_iterator EXTQI [HI SI (DI "TARGET_POWERPC64")]) +(define_mode_iterator EXTQI [SI (DI "TARGET_POWERPC64")]) ; Everything we can extend HImode to. (define_mode_iterator EXTHI [SI (DI "TARGET_POWERPC64")]) @@ -711,7 +711,7 @@ rlwinm %0,%1,0,0xff" [(set_attr "type" "load,shift")]) -(define_insn "*zero_extendqi<mode>2_dot" +(define_insn_and_split "*zero_extendqi<mode>2_dot" [(set (match_operand:CC 2 "cc_reg_operand" "=x,?y") (compare:CC (zero_extend:EXTQI (match_operand:QI 1 "gpc_reg_operand" "r, r")) (const_int 0))) @@ -719,12 +719,19 @@ "rs6000_gen_cell_microcode" "@ andi. %0,%1,0xff - rlwinm %0,%1,0,0xff\;cmpwi %2,%0,0" + #" + "&& reload_completed && cc_reg_not_cr0_operand (operands[2], CCmode)" + [(set (match_dup 0) + (zero_extend:EXTQI (match_dup 1))) + (set (match_dup 2) + (compare:CC (match_dup 0) + (const_int 0)))] + "" [(set_attr "type" "logical") (set_attr "dot" "yes") (set_attr "length" "4,8")]) -(define_insn "*zero_extendqi<mode>2_dot2" +(define_insn_and_split "*zero_extendqi<mode>2_dot2" [(set (match_operand:CC 2 "cc_reg_operand" "=x,?y") (compare:CC (zero_extend:EXTQI (match_operand:QI 1 "gpc_reg_operand" "r, r")) (const_int 0))) @@ -733,7 +740,14 @@ "rs6000_gen_cell_microcode" "@ andi. %0,%1,0xff - rlwinm %0,%1,0,0xff\;cmpwi %2,%0,0" + #" + "&& reload_completed && cc_reg_not_cr0_operand (operands[2], CCmode)" + [(set (match_dup 0) + (zero_extend:EXTQI (match_dup 1))) + (set (match_dup 2) + (compare:CC (match_dup 0) + (const_int 0)))] + "" [(set_attr "type" "logical") (set_attr "dot" "yes") (set_attr "length" "4,8")]) @@ -851,7 +865,7 @@ "extsb %0,%1" [(set_attr "type" "exts")]) -(define_insn "*extendqi<mode>2_dot" +(define_insn_and_split "*extendqi<mode>2_dot" [(set (match_operand:CC 2 "cc_reg_operand" "=x,?y") (compare:CC (sign_extend:EXTQI (match_operand:QI 1 "gpc_reg_operand" "r, r")) (const_int 0))) @@ -859,12 +873,19 @@ "rs6000_gen_cell_microcode" "@ extsb. %0,%1 - extsb %0,%1\;cmpwi %2,%0,0" + #" + "&& reload_completed && cc_reg_not_cr0_operand (operands[2], CCmode)" + [(set (match_dup 0) + (sign_extend:EXTQI (match_dup 1))) + (set (match_dup 2) + (compare:CC (match_dup 0) + (const_int 0)))] + "" [(set_attr "type" "exts") (set_attr "dot" "yes") (set_attr "length" "4,8")]) -(define_insn "*extendqi<mode>2_dot2" +(define_insn_and_split "*extendqi<mode>2_dot2" [(set (match_operand:CC 2 "cc_reg_operand" "=x,?y") (compare:CC (sign_extend:EXTQI (match_operand:QI 1 "gpc_reg_operand" "r, r")) (const_int 0))) @@ -873,7 +894,14 @@ "rs6000_gen_cell_microcode" "@ extsb. %0,%1 - extsb %0,%1\;cmpwi %2,%0,0" + #" + "&& reload_completed && cc_reg_not_cr0_operand (operands[2], CCmode)" + [(set (match_dup 0) + (sign_extend:EXTQI (match_dup 1))) + (set (match_dup 2) + (compare:CC (match_dup 0) + (const_int 0)))] + "" [(set_attr "type" "exts") (set_attr "dot" "yes") (set_attr "length" "4,8")])