[Bug target/67677] New: [6 Regression] r226005 causes "Conditional jump or move depends on uninitialised value(s)"

[trippels at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67677

            Bug ID: 67677
           Summary: [6 Regression] r226005 causes "Conditional jump or
                    move depends on uninitialised value(s)"
           Product: gcc
           Version: 6.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: target
          Assignee: unassigned at gcc dot gnu.org
          Reporter: trippels at gcc dot gnu.org
                CC: segher at gcc dot gnu.org
  Target Milestone: ---
              Host: powerpc64le-unknown-linux-gnu
            Target: powerpc64le-unknown-linux-gnu
             Build: powerpc64le-unknown-linux-gnu

Starting with r226005 --checking=valgrind shows on ppc64le:

==148059== Conditional jump or move depends on uninitialised value(s)
==148059==    at 0x10935248: rs6000_is_valid_mask(rtx_def*, int*, int*,
machine_mode) (rs6000.c:16516)
==148059==    by 0x1093545B: rs6000_is_valid_and_mask(rtx_def*, machine_mode)
(rs6000.c:16565)
==148059==    by 0x105281CF: insn_operand_matches (optabs.c:6527)
==148059==    by 0x105281CF: maybe_legitimize_operand_same_code(insn_code,
unsigned int, expand_operand*) [clone .isra.18] (optabs.c:6555)
==148059==    by 0x1052B8EF: maybe_legitimize_operand (optabs.c:6625)
==148059==    by 0x1052B8EF: maybe_legitimize_operands(insn_code, unsigned int,
unsigned int, expand_operand*) (optabs.c:6690)
==148059==    by 0x1052BD73: maybe_gen_insn(insn_code, unsigned int,
expand_operand*) (optabs.c:6708)
==148059==    by 0x1052C6E7: maybe_expand_insn(insn_code, unsigned int,
expand_operand*) (optabs.c:6751)
==148059==    by 0x1052E667: maybe_emit_op(atomic_op_functions const*,
rtx_def*, rtx_def*, rtx_def*, bool, memmodel, bool) (optabs.c:6293)
==148059==    by 0x105350DF: expand_atomic_fetch_op_no_fallback(rtx_def*,
rtx_def*, rtx_def*, rtx_code, memmodel, bool) (optabs.c:6347)
==148059==    by 0x105352F3: expand_atomic_fetch_op(rtx_def*, rtx_def*,
rtx_def*, rtx_code, memmodel, bool) (optabs.c:6411)
==148059==    by 0x1020D28B: expand_builtin_atomic_fetch_op(machine_mode,
tree_node*, rtx_def*, rtx_code, bool, bool, built_in_function)
(builtins.c:5530)
==148059==    by 0x1021E35F: expand_builtin(tree_node*, rtx_def*, rtx_def*,
machine_mode, int) (builtins.c:6917)
==148059==    by 0x1035AC6F: expand_expr_real_1(tree_node*, rtx_def*,
machine_mode, expand_modifier, rtx_def**, bool) (expr.c:10474)
==148059==
==148059== Conditional jump or move depends on uninitialised value(s)
==148059==    at 0x10935264: exact_log2 (hwint.h:223)
==148059==    by 0x10935264: rs6000_is_valid_mask(rtx_def*, int*, int*,
machine_mode) (rs6000.c:16519)
==148059==    by 0x1093545B: rs6000_is_valid_and_mask(rtx_def*, machine_mode)
(rs6000.c:16565)
==148059==    by 0x105281CF: insn_operand_matches (optabs.c:6527)
==148059==    by 0x105281CF: maybe_legitimize_operand_same_code(insn_code,
unsigned int, expand_operand*) [clone .isra.18] (optabs.c:6555)
==148059==    by 0x1052B8EF: maybe_legitimize_operand (optabs.c:6625)
==148059==    by 0x1052B8EF: maybe_legitimize_operands(insn_code, unsigned int,
unsigned int, expand_operand*) (optabs.c:6690)
==148059==    by 0x1052BD73: maybe_gen_insn(insn_code, unsigned int,
expand_operand*) (optabs.c:6708)
==148059==    by 0x1052C6E7: maybe_expand_insn(insn_code, unsigned int,
expand_operand*) (optabs.c:6751)
==148059==    by 0x1052E667: maybe_emit_op(atomic_op_functions const*,
rtx_def*, rtx_def*, rtx_def*, bool, memmodel, bool) (optabs.c:6293)
==148059==    by 0x105350DF: expand_atomic_fetch_op_no_fallback(rtx_def*,
rtx_def*, rtx_def*, rtx_code, memmodel, bool) (optabs.c:6347)
==148059==    by 0x105352F3: expand_atomic_fetch_op(rtx_def*, rtx_def*,
rtx_def*, rtx_code, memmodel, bool) (optabs.c:6411)
==148059==    by 0x1020D28B: expand_builtin_atomic_fetch_op(machine_mode,
tree_node*, rtx_def*, rtx_code, bool, bool, built_in_function)
(builtins.c:5530)
==148059==    by 0x1021E35F: expand_builtin(tree_node*, rtx_def*, rtx_def*,
machine_mode, int) (builtins.c:6917)
==148059==    by 0x1035AC6F: expand_expr_real_1(tree_node*, rtx_def*,
machine_mode, expand_modifier, rtx_def**, bool) (expr.c:10474)
==148059==
==148059== Conditional jump or move depends on uninitialised value(s)
==148059==    at 0x109352E4: exact_log2 (hwint.h:223)
==148059==    by 0x109352E4: rs6000_is_valid_mask(rtx_def*, int*, int*,
machine_mode) (rs6000.c:16519)
==148059==    by 0x1093545B: rs6000_is_valid_and_mask(rtx_def*, machine_mode)
(rs6000.c:16565)
==148059==    by 0x105281CF: insn_operand_matches (optabs.c:6527)
==148059==    by 0x105281CF: maybe_legitimize_operand_same_code(insn_code,
unsigned int, expand_operand*) [clone .isra.18] (optabs.c:6555)
==148059==    by 0x1052B8EF: maybe_legitimize_operand (optabs.c:6625)
==148059==    by 0x1052B8EF: maybe_legitimize_operands(insn_code, unsigned int,
unsigned int, expand_operand*) (optabs.c:6690)
==148059==    by 0x1052BD73: maybe_gen_insn(insn_code, unsigned int,
expand_operand*) (optabs.c:6708)
==148059==    by 0x1052C6E7: maybe_expand_insn(insn_code, unsigned int,
expand_operand*) (optabs.c:6751)
==148059==    by 0x1052E667: maybe_emit_op(atomic_op_functions const*,
rtx_def*, rtx_def*, rtx_def*, bool, memmodel, bool) (optabs.c:6293)
==148059==    by 0x105350DF: expand_atomic_fetch_op_no_fallback(rtx_def*,
rtx_def*, rtx_def*, rtx_code, memmodel, bool) (optabs.c:6347)
==148059==    by 0x105352F3: expand_atomic_fetch_op(rtx_def*, rtx_def*,
rtx_def*, rtx_code, memmodel, bool) (optabs.c:6411)
==148059==    by 0x1020D28B: expand_builtin_atomic_fetch_op(machine_mode,
tree_node*, rtx_def*, rtx_code, bool, bool, built_in_function)
(builtins.c:5530)
==148059==    by 0x1021E35F: expand_builtin(tree_node*, rtx_def*, rtx_def*,
machine_mode, int) (builtins.c:6917)
==148059==    by 0x1035AC6F: expand_expr_real_1(tree_node*, rtx_def*,
machine_mode, expand_modifier, rtx_def**, bool) (expr.c:10474)
==148059==
==148059== Conditional jump or move depends on uninitialised value(s)
==148059==    at 0x1093527C: exact_log2 (hwint.h:223)
==148059==    by 0x1093527C: rs6000_is_valid_mask(rtx_def*, int*, int*,
machine_mode) (rs6000.c:16520)
==148059==    by 0x1093545B: rs6000_is_valid_and_mask(rtx_def*, machine_mode)
(rs6000.c:16565)
==148059==    by 0x105281CF: insn_operand_matches (optabs.c:6527)
==148059==    by 0x105281CF: maybe_legitimize_operand_same_code(insn_code,
unsigned int, expand_operand*) [clone .isra.18] (optabs.c:6555)
==148059==    by 0x1052B8EF: maybe_legitimize_operand (optabs.c:6625)
==148059==    by 0x1052B8EF: maybe_legitimize_operands(insn_code, unsigned int,
unsigned int, expand_operand*) (optabs.c:6690)
==148059==    by 0x1052BD73: maybe_gen_insn(insn_code, unsigned int,
expand_operand*) (optabs.c:6708)
==148059==    by 0x1052C6E7: maybe_expand_insn(insn_code, unsigned int,
expand_operand*) (optabs.c:6751)
==148059==    by 0x1052E667: maybe_emit_op(atomic_op_functions const*,
rtx_def*, rtx_def*, rtx_def*, bool, memmodel, bool) (optabs.c:6293)
==148059==    by 0x105350DF: expand_atomic_fetch_op_no_fallback(rtx_def*,
rtx_def*, rtx_def*, rtx_code, memmodel, bool) (optabs.c:6347)
==148059==    by 0x105352F3: expand_atomic_fetch_op(rtx_def*, rtx_def*,
rtx_def*, rtx_code, memmodel, bool) (optabs.c:6411)
==148059==    by 0x1020D28B: expand_builtin_atomic_fetch_op(machine_mode,
tree_node*, rtx_def*, rtx_code, bool, bool, built_in_function)
(builtins.c:5530)
==148059==    by 0x1021E35F: expand_builtin(tree_node*, rtx_def*, rtx_def*,
machine_mode, int) (builtins.c:6917)
==148059==    by 0x1035AC6F: expand_expr_real_1(tree_node*, rtx_def*,
machine_mode, expand_modifier, rtx_def**, bool) (expr.c:10474)
==148059==