Make `unreachable()` a built-in compiler-level procedure

4 files changed, 19 insertions, 6 deletions

diff --git a/src/check_builtin.cpp b/src/check_builtin.cpp
index 8108604ba..8f8f7f9e2 100644
--- a/src/check_builtin.cpp
+++ b/src/check_builtin.cpp
@@ -3569,6 +3569,7 @@ bool check_builtin_procedure(CheckerContext *c, Operand *operand, Ast *call, i32
 		operand->mode = Addressing_NoValue;
 		break;
 
+	case BuiltinProc_unreachable:
 	case BuiltinProc_trap:
 	case BuiltinProc_debug_trap:
 		operand->mode = Addressing_NoValue;
diff --git a/src/check_stmt.cpp b/src/check_stmt.cpp
index a6f6f1a7d..451325324 100644
--- a/src/check_stmt.cpp
+++ b/src/check_stmt.cpp
@@ -1,8 +1,5 @@
-bool is_diverging_stmt(Ast *stmt) {
-	if (stmt->kind != Ast_ExprStmt) {
-		return false;
-	}
-	Ast *expr = unparen_expr(stmt->ExprStmt.expr);
+bool is_diverging_expr(Ast *expr) {
+	expr = unparen_expr(expr);
 	if (expr->kind != Ast_CallExpr) {
 		return false;
 	}
@@ -26,6 +23,12 @@ bool is_diverging_stmt(Ast *stmt) {
 	t = base_type(t);
 	return t != nullptr && t->kind == Type_Proc && t->Proc.diverging;
 }
+bool is_diverging_stmt(Ast *stmt) {
+	if (stmt->kind != Ast_ExprStmt) {
+		return false;
+	}
+	return is_diverging_expr(stmt->ExprStmt.expr);
+}
 
 bool contains_deferred_call(Ast *node) {
 	if (node->viral_state_flags & ViralStateFlag_ContainsDeferredProcedure) {
diff --git a/src/checker_builtin_procs.hpp b/src/checker_builtin_procs.hpp
index 3ea6fcdd5..8dd021255 100644
--- a/src/checker_builtin_procs.hpp
+++ b/src/checker_builtin_procs.hpp
@@ -40,6 +40,8 @@ enum BuiltinProcId {
 	BuiltinProc_hadamard_product,
 	BuiltinProc_matrix_flatten,
 
+	BuiltinProc_unreachable,
+
 	BuiltinProc_DIRECTIVE, // NOTE(bill): This is used for specialized hash-prefixed procedures
 
 	// "Intrinsics"
@@ -330,6 +332,8 @@ gb_global BuiltinProc builtin_procs[BuiltinProc_COUNT] = {
 	{STR_LIT("hadamard_product"), 2, false, Expr_Expr, BuiltinProcPkg_builtin},
 	{STR_LIT("matrix_flatten"),   1, false, Expr_Expr, BuiltinProcPkg_builtin},
 
+	{STR_LIT("unreachable"),      0, false, Expr_Expr, BuiltinProcPkg_builtin, /*diverging*/true},
+
 	{STR_LIT(""),                 0, true,  Expr_Expr, BuiltinProcPkg_builtin}, // DIRECTIVE
 
 
@@ -341,7 +345,7 @@ gb_global BuiltinProc builtin_procs[BuiltinProc_COUNT] = {
 	{STR_LIT("alloca"),    2, false, Expr_Expr, BuiltinProcPkg_intrinsics},
 	{STR_LIT("cpu_relax"), 0, false, Expr_Stmt, BuiltinProcPkg_intrinsics},
 
-	{STR_LIT("trap"),               0, false, Expr_Stmt, BuiltinProcPkg_intrinsics, /*diverging*/true},
+	{STR_LIT("trap"),               0, false, Expr_Expr, BuiltinProcPkg_intrinsics, /*diverging*/true},
 	{STR_LIT("debug_trap"),         0, false, Expr_Stmt, BuiltinProcPkg_intrinsics, /*diverging*/false},
 	{STR_LIT("read_cycle_counter"), 0, false, Expr_Expr, BuiltinProcPkg_intrinsics},
 
diff --git a/src/llvm_backend_proc.cpp b/src/llvm_backend_proc.cpp
index 0b0c0794b..a026356a2 100644
--- a/src/llvm_backend_proc.cpp
+++ b/src/llvm_backend_proc.cpp
@@ -1851,6 +1851,11 @@ lbValue lb_build_builtin_proc(lbProcedure *p, Ast *expr, TypeAndValue const &tv,
 			return lb_emit_matrix_flatten(p, m, tv.type);
 		}
 
+	case BuiltinProc_unreachable:
+		LLVMBuildUnreachable(p->builder);
+		return {};
+
+
 	// "Intrinsics"
 
 	case BuiltinProc_alloca: