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add compile error for comptime division by zero

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closes #372
This commit is contained in:
Andrew Kelley 2017-05-14 13:07:45 -04:00
parent 63f6676fee
commit a7570186eb
2 changed files with 52 additions and 19 deletions
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53
src/ir.cpp
View File

@ -8177,18 +8177,25 @@ static TypeTableEntry *ir_analyze_bin_op_math(IrAnalyze *ira, IrInstructionBinOp
if (is_int && is_signed) {
bool ok = false;
if (instr_is_comptime(op1) && instr_is_comptime(op2)) {
BigNum trunc_result;
BigNum floor_result;
if (bignum_div_trunc(&trunc_result, &op1->value.data.x_bignum, &op2->value.data.x_bignum)) {
zig_unreachable();
}
if (bignum_div_floor(&floor_result, &op1->value.data.x_bignum, &op2->value.data.x_bignum)) {
zig_unreachable();
}
if (bignum_cmp_eq(&trunc_result, &floor_result)) {
ok = true;
if (op2->value.data.x_bignum.data.x_uint == 0) {
// the division by zero error will be caught later, but we don't have a
// division function ambiguity problem.
op_id = IrBinOpDivTrunc;
}
ok = true;
} else {
BigNum trunc_result;
BigNum floor_result;
if (bignum_div_trunc(&trunc_result, &op1->value.data.x_bignum, &op2->value.data.x_bignum)) {
zig_unreachable();
}
if (bignum_div_floor(&floor_result, &op1->value.data.x_bignum, &op2->value.data.x_bignum)) {
zig_unreachable();
}
if (bignum_cmp_eq(&trunc_result, &floor_result)) {
ok = true;
op_id = IrBinOpDivTrunc;
}
}
}
if (!ok) {
ir_add_error(ira, &bin_op_instruction->base,
@ -8204,15 +8211,23 @@ static TypeTableEntry *ir_analyze_bin_op_math(IrAnalyze *ira, IrInstructionBinOp
if (is_signed) {
bool ok = false;
if (instr_is_comptime(op1) && instr_is_comptime(op2)) {
BigNum rem_result;
BigNum mod_result;
if (bignum_rem(&rem_result, &op1->value.data.x_bignum, &op2->value.data.x_bignum)) {
zig_unreachable();
if ((is_int && op2->value.data.x_bignum.data.x_uint == 0) ||
(!is_int && op2->value.data.x_bignum.data.x_float == 0.0))
{
// the division by zero error will be caught later, but we don't
// have a remainder function ambiguity problem
ok = true;
} else {
BigNum rem_result;
BigNum mod_result;
if (bignum_rem(&rem_result, &op1->value.data.x_bignum, &op2->value.data.x_bignum)) {
zig_unreachable();
}
if (bignum_mod(&mod_result, &op1->value.data.x_bignum, &op2->value.data.x_bignum)) {
zig_unreachable();
}
ok = bignum_cmp_eq(&rem_result, &mod_result);
}
if (bignum_mod(&mod_result, &op1->value.data.x_bignum, &op2->value.data.x_bignum)) {
zig_unreachable();
}
ok = bignum_cmp_eq(&rem_result, &mod_result);
}
if (!ok) {
ir_add_error(ira, &bin_op_instruction->base,

18
test/compile_errors.zig
View File

@ -1809,4 +1809,22 @@ pub fn addCases(cases: &tests.CompileErrorContext) {
\\}
,
".tmp_source.zig:3:25: error: attempt to cast negative value to unsigned integer");
cases.add("compile-time division by zero",
\\comptime {
\\ const a: i32 = 1;
\\ const b: i32 = 0;
\\ const c = a / b;
\\}
,
".tmp_source.zig:4:17: error: division by zero is undefined");
cases.add("compile-time remainder division by zero",
\\comptime {
\\ const a: i32 = 1;
\\ const b: i32 = 0;
\\ const c = a % b;
\\}
,
".tmp_source.zig:4:17: error: division by zero is undefined");
}