Commit a7570186ebdffd97878a983b8e8a09902841e279 | zig

author	Andrew Kelley <andrew@ziglang.org> 2017-05-14 13:07:45-04:00
committer	Andrew Kelley <andrew@ziglang.org> 2017-05-14 13:07:45-04:00
log	a7570186ebdffd97878a983b8e8a09902841e279
tree	68ad4b544efe41eda086a8af5682ee383d5efbb7
parent	63f6676fee83883736af794eaddb4d0ccb890c06

add compile error for comptime division by zero

closes #372

2 files changed, 52 insertions(+), 19 deletions(-)

src
- ir.cpp
test
- compile_errors.zig

src/ir.cpp+34-19

 @@ -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;
+				if (op2->value.data.x_bignum.data.x_uint == 0) {
-                BigNum floor_result;
+                    // the division by zero error will be caught later, but we don't have a
-                if (bignum_div_trunc(&trunc_result, &op1->value.data.x_bignum, &op2->value.data.x_bignum)) {
+                    // division function ambiguity problem.
-                    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;
-                }
+					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;
+                if ((is_int && op2->value.data.x_bignum.data.x_uint == 0) ||
-                BigNum mod_result;
+                    (!is_int && op2->value.data.x_bignum.data.x_float == 0.0))
-                if (bignum_rem(&rem_result, &op1->value.data.x_bignum, &op2->value.data.x_bignum)) {
+                {
-                    zig_unreachable();
+                    // the division by zero error will be caught later, but we don't
-                }
+                    // have a remainder function ambiguity problem
-                if (bignum_mod(&mod_result, &op1->value.data.x_bignum, &op2->value.data.x_bignum)) {
+                    ok = true;
-                    zig_unreachable();
+                } 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);
                 }
-                ok = bignum_cmp_eq(&rem_result, &mod_result);
             }
             if (!ok) {
                 ir_add_error(ira, &bin_op_instruction->base,

test/compile_errors.zig+18

...	@@ -1809,4 +1809,22 @@ pub fn addCases(cases: &tests.CompileErrorContext) {	...	@@ -1809,4 +1809,22 @@ pub fn addCases(cases: &tests.CompileErrorContext) {
1809	\\}	1809	\\}
1810	,	1810	,
1811	".tmp_source.zig:3:25: error: attempt to cast negative value to unsigned integer");	1811	".tmp_source.zig:3:25: error: attempt to cast negative value to unsigned integer");
		1812
		1813	cases.add("compile-time division by zero",
		1814	\\comptime {
		1815	\\ const a: i32 = 1;
		1816	\\ const b: i32 = 0;
		1817	\\ const c = a / b;
		1818	\\}
		1819	,
		1820	".tmp_source.zig:4:17: error: division by zero is undefined");
		1821
		1822	cases.add("compile-time remainder division by zero",
		1823	\\comptime {
		1824	\\ const a: i32 = 1;
		1825	\\ const b: i32 = 0;
		1826	\\ const c = a % b;
		1827	\\}
		1828	,
		1829	".tmp_source.zig:4:17: error: division by zero is undefined");
1812	}	1830	}