diff --git a/src/panfrost/bifrost/bi_ra.c b/src/panfrost/bifrost/bi_ra.c
index 8a7fa6309d9..4a15b560abf 100644
--- a/src/panfrost/bifrost/bi_ra.c
+++ b/src/panfrost/bifrost/bi_ra.c
@@ -314,6 +314,10 @@ bi_allocate_registers(bi_context *ctx, bool *success, bool full_regs)
                 full_regs ? BITFIELD64_MASK(64) :
                 (BITFIELD64_MASK(16) | (BITFIELD64_MASK(16) << 48));
 
+        /* To test spilling, mimic a small register file */
+        if (bifrost_debug & BIFROST_DBG_SPILL && !ctx->inputs->is_blend)
+                default_affinity &= BITFIELD64_MASK(48) << 8;
+
         bi_foreach_instr_global(ctx, ins) {
                 bi_foreach_dest(ins, d) {
                         unsigned dest = bi_get_node(ins->dest[d]);
diff --git a/src/panfrost/bifrost/bifrost.h b/src/panfrost/bifrost/bifrost.h
index 6dce0c53b38..d80844e012f 100644
--- a/src/panfrost/bifrost/bifrost.h
+++ b/src/panfrost/bifrost/bifrost.h
@@ -47,6 +47,7 @@ extern "C" {
 #define BIFROST_DBG_NOIDVS      0x0200
 #define BIFROST_DBG_NOSB        0x0400
 #define BIFROST_DBG_NOPRELOAD   0x0800
+#define BIFROST_DBG_SPILL       0x1000
 
 extern int bifrost_debug;
 
diff --git a/src/panfrost/bifrost/bifrost_compile.c b/src/panfrost/bifrost/bifrost_compile.c
index 5464e581024..12c09a68282 100644
--- a/src/panfrost/bifrost/bifrost_compile.c
+++ b/src/panfrost/bifrost/bifrost_compile.c
@@ -52,6 +52,7 @@ static const struct debug_named_value bifrost_debug_options[] = {
         {"noidvs",    BIFROST_DBG_NOIDVS,       "Disable IDVS"},
         {"nosb",      BIFROST_DBG_NOSB,         "Disable scoreboarding"},
         {"nopreload", BIFROST_DBG_NOPRELOAD,    "Disable message preloading"},
+        {"spill",     BIFROST_DBG_SPILL,        "Test register spilling"},
         DEBUG_NAMED_VALUE_END
 };