diff --git a/ir.c b/ir.c
index ca2ccd6..cc2b994 100644
--- a/ir.c
+++ b/ir.c
@@ -280,6 +280,7 @@ void ir_init(ir_ctx *ctx, ir_ref consts_limit, ir_ref insns_limit)
 
 	ctx->use_lists = NULL;
 	ctx->use_edges = NULL;
+	ctx->use_edges_count = 0;
 
 	ctx->cfg_blocks_count = 0;
 	ctx->cfg_edges_count = 0;
@@ -939,6 +940,7 @@ void ir_build_def_use_lists(ir_ctx *ctx)
 	}
 
 	ctx->use_edges = edges;
+	ctx->use_edges_count = edges_count;
 	ctx->use_lists = lists;
 }
 
diff --git a/ir.h b/ir.h
index 5416261..a6ff51a 100644
--- a/ir.h
+++ b/ir.h
@@ -440,6 +440,7 @@ typedef struct _ir_ctx {
 	ir_insn            fold_insn;
 	ir_use_list       *use_lists;         /* def->use lists for each instruction */
 	ir_ref            *use_edges;
+	uint32_t           use_edges_count;
 	uint32_t           cfg_blocks_count;
 	uint32_t           cfg_edges_count;
 	ir_block          *cfg_blocks;        /* list of Basic Blocks (starts from 1) */
diff --git a/ir_gcm.c b/ir_gcm.c
index 59740fb..cbbe2ef 100644
--- a/ir_gcm.c
+++ b/ir_gcm.c
@@ -581,6 +581,7 @@ restart:
 	}
 
 	new_ctx.use_edges = edges;
+	new_ctx.use_edges_count = edges_count;
 	new_ctx.use_lists = lists;
 
 	if (ctx->cfg_blocks) {
diff --git a/ir_sccp.c b/ir_sccp.c
index 951b1d9..1776f10 100644
--- a/ir_sccp.c
+++ b/ir_sccp.c
@@ -196,11 +196,17 @@ static void ir_sccp_add_to_use_list(ir_ctx *ctx, ir_ref to, ir_ref ref)
 	ir_use_list *use_list = &ctx->use_lists[to];
 	ir_ref n = use_list->refs + use_list->count;
 
-	if (ctx->use_edges[n] == IR_UNUSED) {
+	if (n < ctx->use_edges_count && ctx->use_edges[n] == IR_UNUSED) {
 		ctx->use_edges[n] = ref;
 		use_list->count++;
 	} else {
-		IR_ASSERT(0 && "NIY: insert def->use edges"); // TODO:
+		/* Reallocate the whole edges buffer (this is inefficient) */
+		ctx->use_edges = ir_mem_realloc(ctx->use_edges, (ctx->use_edges_count + use_list->count + 1) * sizeof(ir_ref));
+		memcpy(ctx->use_edges + ctx->use_edges_count, ctx->use_edges + use_list->refs, use_list->count * sizeof(ir_ref));
+		use_list->refs = ctx->use_edges_count;
+		ctx->use_edges[use_list->refs + use_list->count] = ref;
+		use_list->count++;
+		ctx->use_edges_count += use_list->count;
 	}
 }
 #endif