diff options
Diffstat (limited to 'simplify.c')
| -rw-r--r-- | simplify.c | 8 |
1 files changed, 8 insertions, 0 deletions
@@ -1090,6 +1090,8 @@ static int simplify_compare_constant(struct instruction *insn, long long value) return replace_with_pseudo(insn, value_pseudo(0)); if (value == 1) // (x < 1) --> (x == 0) return replace_binop_value(insn, OP_SET_EQ, 0); + else if (value == bits) // (x < ~0) --> (x != ~0) + return replace_binop_value(insn, OP_SET_NE, value); else // (x < y) --> (x <= (y-1)) changed |= replace_binop_value(insn, OP_SET_BE, value - 1); break; @@ -1098,6 +1100,8 @@ static int simplify_compare_constant(struct instruction *insn, long long value) return replace_with_pseudo(insn, value_pseudo(1)); if (value == 1) // (x >= 1) --> (x != 0) return replace_binop_value(insn, OP_SET_NE, 0); + else if (value == bits) // (x >= ~0) --> (x == ~0) + return replace_binop_value(insn, OP_SET_EQ, value); else // (x >= y) --> (x > (y-1) changed |= replace_binop_value(insn, OP_SET_A, value - 1); break; @@ -1106,12 +1110,16 @@ static int simplify_compare_constant(struct instruction *insn, long long value) return replace_opcode(insn, OP_SET_EQ); if (value == bits) // (x <= ~0) --> 1 return replace_with_pseudo(insn, value_pseudo(1)); + if (value == (bits - 1)) // (x <= ~1) --> (x != ~0) + return replace_binop_value(insn, OP_SET_NE, bits); break; case OP_SET_A: if (!value) // (x > 0) --> (x != 0) return replace_opcode(insn, OP_SET_NE); if (value == bits) // (x > ~0) --> 0 return replace_with_pseudo(insn, value_pseudo(0)); + if (value == (bits - 1)) // (x > ~1) --> (x == ~0) + return replace_binop_value(insn, OP_SET_EQ, bits); break; } return changed; |