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fix dereferencing a zero bit type

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Before only u0 was special cased in handling a dereference;
now all zero bit types are handled the same way. Dereferencing
a pointer to a zero bit type always gives a comptime-known
result.

This previously had been failing on master branch but went unnoticed
because until 846f72b57cb5 the CI server was mistakenly not actually
running the single-threaded tests with --single-threaded.

This fixes the standard library tests with --single-threaded
--release-fast.
This commit is contained in:
Andrew Kelley 2019-04-05 20:18:26 -04:00
parent 3854bb9198
commit 83390bdfdd
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GPG Key ID: 7C5F548F728501A9
1 changed files with 17 additions and 14 deletions
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31
src/ir.cpp
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@ -10702,15 +10702,6 @@ static IrInstruction *ir_analyze_enum_to_int(IrAnalyze *ira, IrInstruction *sour
ZigType *tag_type = enum_type->data.enumeration.tag_int_type;
assert(tag_type->id == ZigTypeIdInt || tag_type->id == ZigTypeIdComptimeInt);
if (instr_is_comptime(enum_target)) {
ConstExprValue *val = ir_resolve_const(ira, enum_target, UndefBad);
if (!val)
return ira->codegen->invalid_instruction;
IrInstruction *result = ir_const(ira, source_instr, tag_type);
init_const_bigint(&result->value, tag_type, &val->data.x_enum_tag);
return result;
}
// If there is only one possible tag, then we know at comptime what it is.
if (enum_type->data.enumeration.layout == ContainerLayoutAuto &&
enum_type->data.enumeration.src_field_count == 1)
@ -10722,6 +10713,15 @@ static IrInstruction *ir_analyze_enum_to_int(IrAnalyze *ira, IrInstruction *sour
return result;
}
if (instr_is_comptime(enum_target)) {
ConstExprValue *val = ir_resolve_const(ira, enum_target, UndefBad);
if (!val)
return ira->codegen->invalid_instruction;
IrInstruction *result = ir_const(ira, source_instr, tag_type);
init_const_bigint(&result->value, tag_type, &val->data.x_enum_tag);
return result;
}
IrInstruction *result = ir_build_widen_or_shorten(&ira->new_irb, source_instr->scope,
source_instr->source_node, enum_target);
result->value.type = tag_type;
@ -11809,11 +11809,14 @@ static IrInstruction *ir_get_deref(IrAnalyze *ira, IrInstruction *source_instruc
return ira->codegen->invalid_instruction;
} else if (type_entry->id == ZigTypeIdPointer) {
ZigType *child_type = type_entry->data.pointer.child_type;
// dereferencing a *u0 is comptime known to be 0
if (child_type->id == ZigTypeIdInt && child_type->data.integral.bit_count == 0) {
IrInstruction *result = ir_const(ira, source_instruction, child_type);
init_const_unsigned_negative(&result->value, child_type, 0, false);
return result;
// if the child type has one possible value, the deref is comptime
switch (type_has_one_possible_value(ira->codegen, child_type)) {
case OnePossibleValueInvalid:
return ira->codegen->invalid_instruction;
case OnePossibleValueYes:
return ir_const(ira, source_instruction, child_type);
case OnePossibleValueNo:
break;
}
if (instr_is_comptime(ptr)) {
if (ptr->value.special == ConstValSpecialUndef) {