From cc6376058784aa7a910e93c31ac8bd819de4e187 Mon Sep 17 00:00:00 2001
From: LemonBoy <thatlemon@gmail.com>
Date: Mon, 9 Sep 2019 18:51:13 +0200
Subject: Allow comparison between union tag and enum literal

Closes #2810
---
 src/ir.cpp | 25 +++++++++++++++++++++++++
 1 file changed, 25 insertions(+)

(limited to 'src/ir.cpp')

diff --git a/src/ir.cpp b/src/ir.cpp
index 6b71fa8d17..bbea993162 100644
--- a/src/ir.cpp
+++ b/src/ir.cpp
@@ -13228,6 +13228,31 @@ static IrInstruction *ir_analyze_bin_op_cmp(IrAnalyze *ira, IrInstructionBinOp *
         ir_add_error_node(ira, source_node, buf_sprintf("comparison of '%s' with null",
             buf_ptr(&non_null_type->name)));
         return ira->codegen->invalid_instruction;
+    } else if (is_equality_cmp && (
+        (op1->value.type->id == ZigTypeIdEnumLiteral && op2->value.type->id == ZigTypeIdUnion) ||
+        (op2->value.type->id == ZigTypeIdEnumLiteral && op1->value.type->id == ZigTypeIdUnion)))
+    {
+        // Support equality comparison between a union's tag value and a enum literal
+        IrInstruction *union_val = op1->value.type->id == ZigTypeIdUnion ? op1 : op2;
+        IrInstruction *enum_val = op1->value.type->id == ZigTypeIdUnion ? op2 : op1;
+
+        ZigType *tag_type = union_val->value.type->data.unionation.tag_type;
+        assert(tag_type != nullptr);
+
+        IrInstruction *casted_union = ir_implicit_cast(ira, union_val, tag_type);
+        if (type_is_invalid(casted_union->value.type))
+            return ira->codegen->invalid_instruction;
+
+        IrInstruction *casted_val = ir_implicit_cast(ira, enum_val, tag_type);
+        if (type_is_invalid(casted_val->value.type))
+            return ira->codegen->invalid_instruction;
+
+        IrInstruction *result = ir_build_bin_op(&ira->new_irb,
+            bin_op_instruction->base.scope, bin_op_instruction->base.source_node,
+            op_id, casted_union, casted_val, bin_op_instruction->safety_check_on);
+        result->value.type = ira->codegen->builtin_types.entry_bool;
+
+        return result;
     }
 
     if (op1->value.type->id == ZigTypeIdErrorSet && op2->value.type->id == ZigTypeIdErrorSet) {
-- 
cgit v1.2.3


From 4b1cd45472cab5569438fef018990fbe8043c6c3 Mon Sep 17 00:00:00 2001
From: LemonBoy <thatlemon@gmail.com>
Date: Mon, 9 Sep 2019 19:09:56 +0200
Subject: Comptime folding of enum/union comparisons

---
 src/ir.cpp                     | 15 +++++++++++++++
 test/stage1/behavior/union.zig |  7 ++++++-
 2 files changed, 21 insertions(+), 1 deletion(-)

(limited to 'src/ir.cpp')

diff --git a/src/ir.cpp b/src/ir.cpp
index bbea993162..196e84eead 100644
--- a/src/ir.cpp
+++ b/src/ir.cpp
@@ -13247,6 +13247,21 @@ static IrInstruction *ir_analyze_bin_op_cmp(IrAnalyze *ira, IrInstructionBinOp *
         if (type_is_invalid(casted_val->value.type))
             return ira->codegen->invalid_instruction;
 
+        if (instr_is_comptime(casted_union)) {
+            ConstExprValue *const_union_val = ir_resolve_const(ira, casted_union, UndefBad);
+            if (!const_union_val)
+                return ira->codegen->invalid_instruction;
+
+            ConstExprValue *const_enum_val = ir_resolve_const(ira, casted_val, UndefBad);
+            if (!const_enum_val)
+                return ira->codegen->invalid_instruction;
+
+            Cmp cmp_result = bigint_cmp(&const_union_val->data.x_union.tag, &const_enum_val->data.x_enum_tag);
+            bool bool_result = (op_id == IrBinOpCmpEq) ? cmp_result == CmpEQ : cmp_result != CmpEQ;
+
+            return ir_const_bool(ira, &bin_op_instruction->base, bool_result);
+        }
+
         IrInstruction *result = ir_build_bin_op(&ira->new_irb,
             bin_op_instruction->base.scope, bin_op_instruction->base.source_node,
             op_id, casted_union, casted_val, bin_op_instruction->safety_check_on);
diff --git a/test/stage1/behavior/union.zig b/test/stage1/behavior/union.zig
index 1f8ca82958..7c5c653275 100644
--- a/test/stage1/behavior/union.zig
+++ b/test/stage1/behavior/union.zig
@@ -468,7 +468,7 @@ test "union no tag with struct member" {
     u.foo();
 }
 
-test "comparison between union and enum literal" {
+fn testComparison() void {
     var x = Payload{.A = 42};
     expect(x == .A);
     expect(x != .B);
@@ -477,3 +477,8 @@ test "comparison between union and enum literal" {
     expect((x == .C) == false);
     expect((x != .A) == false);
 }
+
+test "comparison between union and enum literal" {
+    testComparison();
+    comptime testComparison();
+}
-- 
cgit v1.2.3