stage2: type inference for local var

BRANCH_TODO

@@ -0,0 +1,2 @@
+ * no need for payload on inferred_alloc for the type
+ * compile error for "variable of type '{}' must be const or comptime" after resolving types

src/astgen.zig

@@ -625,9 +625,9 @@ fn varDecl(
                 const alloc = try addZIRUnOp(mod, scope, name_src, .alloc_mut, type_inst);
                 break :a .{ .alloc = alloc, .result_loc = .{ .ptr = alloc } };
             } else a: {
-                const alloc = try addZIRNoOp(mod, scope, name_src, .alloc_inferred_mut);
-                resolve_inferred_alloc = alloc;
-                break :a .{ .alloc = alloc, .result_loc = .{ .inferred_ptr = alloc.castTag(.alloc_inferred_mut).? } };
+                const alloc = try addZIRNoOpT(mod, scope, name_src, .alloc_inferred);
+                resolve_inferred_alloc = &alloc.base;
+                break :a .{ .alloc = &alloc.base, .result_loc = .{ .inferred_ptr = alloc } };
             };
             const init_inst = try expr(mod, scope, var_data.result_loc, init_node);
             if (resolve_inferred_alloc) |inst| {

src/codegen/c.zig

@@ -275,7 +275,6 @@ pub fn generate(file: *C, module: *Module, decl: *Decl) !void {
         try writer.writeAll(" {");
 
         const func: *Module.Fn = func_payload.data;
-        //func.dump(module.*);
         const instructions = func.analysis.success.instructions;
         if (instructions.len > 0) {
             try writer.writeAll("\n");
@@ -297,6 +296,7 @@ pub fn generate(file: *C, module: *Module, decl: *Decl) !void {
                     .cmp_neq => try genBinOp(&ctx, file, inst.castTag(.cmp_neq).?, "!="),
                     .dbg_stmt => try genDbgStmt(&ctx, inst.castTag(.dbg_stmt).?),
                     .intcast => try genIntCast(&ctx, file, inst.castTag(.intcast).?),
+                    .load => try genLoad(&ctx, file, inst.castTag(.load).?),
                     .ret => try genRet(&ctx, file, inst.castTag(.ret).?),
                     .retvoid => try genRetVoid(file),
                     .store => try genStore(&ctx, file, inst.castTag(.store).?),
@@ -431,6 +431,16 @@ fn genRetVoid(file: *C) !?[]u8 {
     return null;
 }
 
+fn genLoad(ctx: *Context, file: *C, inst: *Inst.UnOp) !?[]u8 {
+    const operand = try ctx.resolveInst(inst.operand);
+    const writer = file.main.writer();
+    try indent(file);
+    const local_name = try ctx.name();
+    try renderTypeAndName(ctx, writer, inst.base.ty, local_name, .Const);
+    try writer.print(" = *{s};\n", .{operand});
+    return local_name;
+}
+
 fn genRet(ctx: *Context, file: *C, inst: *Inst.UnOp) !?[]u8 {
     try indent(file);
     const writer = file.main.writer();
@@ -442,7 +452,6 @@ fn genIntCast(ctx: *Context, file: *C, inst: *Inst.UnOp) !?[]u8 {
     if (inst.base.isUnused())
         return null;
     try indent(file);
-    const op = inst.operand;
     const writer = file.main.writer();
     const name = try ctx.name();
     const from = try ctx.resolveInst(inst.operand);

test/stage2/cbe.zig

@@ -52,7 +52,7 @@ pub fn addCases(ctx: *TestContext) !void {
     }
 
     {
-        var case = ctx.exeFromCompiledC("inferred local const", .{});
+        var case = ctx.exeFromCompiledC("inferred local const and var", .{});
 
         case.addCompareOutput(
             \\fn add(a: i32, b: i32) i32 {
@@ -61,7 +61,9 @@ pub fn addCases(ctx: *TestContext) !void {
             \\
             \\export fn main() c_int {
             \\    const x = add(1, 2);
-            \\    return x - 3;
+            \\    var y = add(3, 0);
+            \\    y -= x;
+            \\    return y;
             \\}
         , "");
     }