diff --git a/ir_aarch64.dasc b/ir_aarch64.dasc
index 5a8dba1..94c95d6 100644
--- a/ir_aarch64.dasc
+++ b/ir_aarch64.dasc
@@ -716,6 +716,8 @@ binop_fp:
 			return IR_CALL;
 		case IR_VAR:
 			return IR_SKIPPED | IR_VAR;
+		case IR_PARAM:
+			return ctx->use_lists[ref].count > 0 ? IR_PARAM : IR_SKIPPED | IR_PARAM;
 		case IR_ALLOCA:
 			if (ctx->flags & IR_FUNCTION) {
 				ctx->flags |= IR_USE_FRAME_POINTER | IR_HAS_ALLOCA;
diff --git a/ir_ra.c b/ir_ra.c
index 22fa88c..b534894 100644
--- a/ir_ra.c
+++ b/ir_ra.c
@@ -62,7 +62,7 @@ static int ir_assign_virtual_registers_slow(ir_ctx *ctx)
 		insn += n;
 		while (i < bb->end) {
 			flags = ir_op_flags[insn->op];
-			if (((flags & IR_OP_FLAG_DATA) && ctx->use_lists[i].count > 0)
+			if (((flags & IR_OP_FLAG_DATA) && insn->op != IR_VAR && (insn->op != IR_PARAM || ctx->use_lists[i].count > 0))
 			 || ((flags & IR_OP_FLAG_MEM) && ctx->use_lists[i].count > 1)) {
 				if (!ctx->rules || !(ctx->rules[i] & (IR_FUSED|IR_SKIPPED))) {
 					vregs[i] = ++vregs_count;
@@ -99,7 +99,7 @@ int ir_assign_virtual_registers(ir_ctx *ctx)
 		if (ctx->rules[i] && !(ctx->rules[i] & (IR_FUSED|IR_SKIPPED))) {
 			uint32_t flags = ir_op_flags[insn->op];
 
-			if (((flags & IR_OP_FLAG_DATA) && ctx->use_lists[i].count > 0)
+			if ((flags & IR_OP_FLAG_DATA)
 			 || ((flags & IR_OP_FLAG_MEM) && ctx->use_lists[i].count > 1)) {
 				v = ++vregs_count;
 			}
@@ -323,7 +323,7 @@ static ir_live_interval *ir_fix_live_range(ir_ctx *ctx, int v, ir_live_pos old_s
 		p = p->next;
 	}
 #endif
-	IR_ASSERT(p && p->start == old_start);
+	IR_ASSERT(ival && p->start == old_start);
 	p->start = new_start;
 	return ival;
 }
diff --git a/ir_x86.dasc b/ir_x86.dasc
index 3508e1d..43b66d2 100644
--- a/ir_x86.dasc
+++ b/ir_x86.dasc
@@ -1365,6 +1365,8 @@ binop_fp:
 			return insn->op;
 		case IR_VAR:
 			return IR_SKIPPED | IR_VAR;
+		case IR_PARAM:
+			return ctx->use_lists[ref].count > 0 ? IR_PARAM : IR_SKIPPED | IR_PARAM;
 		case IR_ALLOCA:
 			/* alloca() may be use only in functions */
 			if (ctx->flags & IR_FUNCTION) {
diff --git a/tests/bugs/gh-00033.irt b/tests/bugs/gh-00033.irt
new file mode 100644
index 0000000..ae60593
--- /dev/null
+++ b/tests/bugs/gh-00033.irt
@@ -0,0 +1,28 @@
+--TEST--
+GH-33: IR program failed to compile with "-O0" "-S" options
+--TARGET--
+x86_64
+--ARGS--
+-O0 -S
+--CODE--
+{
+	uintptr_t c_1 = 0;
+	bool c_2 = 0;
+	bool c_3 = 1;
+	int32_t c_4 = 10;
+	l_1 = START(l_4);
+	int32_t d_2 = PARAM(l_1, "x", 0);
+	int32_t d_3 = DIV(d_2, c_4);
+	l_4 = RETURN(l_1, null);
+}
+--EXPECT--
+test:
+	subq $8, %rsp
+	movl %edi, (%rsp)
+	movl (%rsp), %eax
+	movl $0xa, %ecx
+	cltd
+	idivl %ecx
+	movl %eax, 4(%rsp)
+	addq $8, %rsp
+	retq