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stage2: apply type coercion in if expressions

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When setting the break value in an if expression we must explicitly
check if a result location type coercion that needs to happen. This was
already done for switch expression, so let's just imitate that check
and fix for if expressions. To make this possible, we now also propagate
`rl_ty_inst` to sub scopes.
This commit is contained in:
John Schmidt 2022-02-06 22:11:41 +01:00 committed by Andrew Kelley
parent adc9a282d8
commit fd1284ebd0
2 changed files with 40 additions and 8 deletions
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42
src/AstGen.zig
View File

@ -5118,8 +5118,10 @@ fn setCondBrPayloadElideBlockStorePtr(
const astgen = then_scope.astgen; const astgen = then_scope.astgen;
const then_body = then_scope.instructionsSliceUpto(else_scope); const then_body = then_scope.instructionsSliceUpto(else_scope);
const else_body = else_scope.instructionsSlice(); const else_body = else_scope.instructionsSlice();
const then_body_len = @intCast(u32, then_body.len + @boolToInt(then_break != 0)); const has_then_break = then_break != 0;
const else_body_len = @intCast(u32, else_body.len + @boolToInt(else_break != 0)); const has_else_break = else_break != 0;
const then_body_len = @intCast(u32, then_body.len + @boolToInt(has_then_break));
const else_body_len = @intCast(u32, else_body.len + @boolToInt(has_else_break));
try astgen.extra.ensureUnusedCapacity(astgen.gpa, @typeInfo(Zir.Inst.CondBr).Struct.fields.len + try astgen.extra.ensureUnusedCapacity(astgen.gpa, @typeInfo(Zir.Inst.CondBr).Struct.fields.len +
then_body_len + else_body_len); then_body_len + else_body_len);
@ -5135,26 +5137,49 @@ fn setCondBrPayloadElideBlockStorePtr(
const then_body_len_index = condbr_pl + 1; const then_body_len_index = condbr_pl + 1;
const else_body_len_index = condbr_pl + 2; const else_body_len_index = condbr_pl + 2;
// The break instructions need to have their operands coerced if the
// switch's result location is a `ty`. In this case we overwrite the
// `store_to_block_ptr` instruction with an `as` instruction and repurpose
// it as the break operand.
for (then_body) |src_inst| { for (then_body) |src_inst| {
if (zir_tags[src_inst] == .store_to_block_ptr) { if (zir_tags[src_inst] == .store_to_block_ptr and
if (zir_datas[src_inst].bin.lhs == block_ptr) { zir_datas[src_inst].bin.lhs == block_ptr)
{
if (then_scope.rl_ty_inst != .none and has_then_break) {
zir_tags[src_inst] = .as;
zir_datas[src_inst].bin = .{
.lhs = then_scope.rl_ty_inst,
.rhs = zir_datas[then_break].@"break".operand,
};
zir_datas[then_break].@"break".operand = indexToRef(src_inst);
} else {
astgen.extra.items[then_body_len_index] -= 1; astgen.extra.items[then_body_len_index] -= 1;
continue; continue;
} }
} }
astgen.extra.appendAssumeCapacity(src_inst); astgen.extra.appendAssumeCapacity(src_inst);
} }
if (then_break != 0) astgen.extra.appendAssumeCapacity(then_break); if (has_then_break) astgen.extra.appendAssumeCapacity(then_break);
for (else_body) |src_inst| { for (else_body) |src_inst| {
if (zir_tags[src_inst] == .store_to_block_ptr) { if (zir_tags[src_inst] == .store_to_block_ptr and
if (zir_datas[src_inst].bin.lhs == block_ptr) { zir_datas[src_inst].bin.lhs == block_ptr)
{
if (else_scope.rl_ty_inst != .none and has_else_break) {
zir_tags[src_inst] = .as;
zir_datas[src_inst].bin = .{
.lhs = else_scope.rl_ty_inst,
.rhs = zir_datas[else_break].@"break".operand,
};
zir_datas[else_break].@"break".operand = indexToRef(src_inst);
} else {
astgen.extra.items[else_body_len_index] -= 1; astgen.extra.items[else_body_len_index] -= 1;
continue; continue;
} }
} }
astgen.extra.appendAssumeCapacity(src_inst); astgen.extra.appendAssumeCapacity(src_inst);
} }
if (else_break != 0) astgen.extra.appendAssumeCapacity(else_break); if (has_else_break) astgen.extra.appendAssumeCapacity(else_break);
} }
fn whileExpr( fn whileExpr(
@ -9460,6 +9485,7 @@ const GenZir = struct {
.decl_node_index = gz.decl_node_index, .decl_node_index = gz.decl_node_index,
.decl_line = gz.decl_line, .decl_line = gz.decl_line,
.parent = scope, .parent = scope,
.rl_ty_inst = gz.rl_ty_inst,
.astgen = gz.astgen, .astgen = gz.astgen,
.suspend_node = gz.suspend_node, .suspend_node = gz.suspend_node,
.nosuspend_node = gz.nosuspend_node, .nosuspend_node = gz.nosuspend_node,

6
test/behavior/basic.zig
View File

@ -693,3 +693,9 @@ test "variable name containing underscores does not shadow int primitive" {
_ = u6__4; _ = u6__4;
_ = i2_04_8; _ = i2_04_8;
} }
test "if expression type coercion" {
var cond: bool = true;
const x: u16 = if (cond) 1 else 0;
try expect(@as(u16, x) == 1);
}