From 0f33afbe56cd1124e1ea16c937411c01f7fa2519 Mon Sep 17 00:00:00 2001
From: Millaguie <javi@millaguie.net>
Date: Mon, 10 Aug 2026 18:48:19 +0200
Subject: [PATCH] tests : declare the generic DT3 vec_dot weak in the parity
 test

Builds without a native DT3 kernel rename the generic symbol to
ggml_vec_dot_dt3_q8_0 (arch-fallback.h), so test-dt3 failed to link on
them. With a weak declaration the test links everywhere and skips,
loudly, when there is no separate generic to compare against. MSVC has
no weak symbols, so there the test is compiled out.
---
 tests/test-dt3.cpp | 24 ++++++++++++++++++++----
 1 file changed, 20 insertions(+), 4 deletions(-)

diff --git a/tests/test-dt3.cpp b/tests/test-dt3.cpp
index d116e3129..309876125 100644
--- a/tests/test-dt3.cpp
+++ b/tests/test-dt3.cpp
@@ -479,10 +479,15 @@ static int test_vec_dot(const ggml_type_traits_cpu * qfns_cpu) {
     return num_failed;
 }
 
-// the scalar reference implementation, always compiled into ggml-cpu; on
-// architectures without a native kernel the dispatched vec_dot IS this
-// function and the parity test below passes trivially
-extern "C" void ggml_vec_dot_dt3_q8_0_generic(int n, float * s, size_t bs, const void * vx, size_t bx, const void * vy, size_t by, int nrc);
+// the scalar reference implementation. The symbol only exists on builds with
+// a native DT3 kernel: without one, arch-fallback.h renames the generic to
+// ggml_vec_dot_dt3_q8_0 and there is nothing to compare against, so the
+// reference is declared weak and the parity test skips when it is absent.
+#if defined(_MSC_VER)
+#define DT3_NO_WEAK_SYMBOLS
+#else
+extern "C" void ggml_vec_dot_dt3_q8_0_generic(int n, float * s, size_t bs, const void * vx, size_t bx, const void * vy, size_t by, int nrc) __attribute__((weak));
+#endif
 
 // the dispatched (possibly vectorized) vec_dot must match the generic scalar
 // implementation exactly — the actual function is called, not a re-derivation
@@ -492,6 +497,16 @@ extern "C" void ggml_vec_dot_dt3_q8_0_generic(int n, float * s, size_t bs, const
 static int test_vec_dot_arch_parity(const ggml_type_traits_cpu * qfns_cpu) {
     int num_failed = 0;
 
+#if defined(DT3_NO_WEAK_SYMBOLS)
+    (void) qfns_cpu;
+    printf("(skipping vec_dot arch parity: no weak symbol support)\n");
+    return num_failed;
+#else
+    if (ggml_vec_dot_dt3_q8_0_generic == nullptr) {
+        printf("(skipping vec_dot arch parity: this build has no separate generic vec_dot)\n");
+        return num_failed;
+    }
+
     const auto * vdot_traits = ggml_get_type_traits_cpu(qfns_cpu->vec_dot_type);
 
     const int nblocks = 3;
@@ -560,6 +575,7 @@ static int test_vec_dot_arch_parity(const ggml_type_traits_cpu * qfns_cpu) {
     }
 
     return num_failed;
+#endif
 }
 
 // --dequant IN.bin OUT.f32 : dequantize raw DT3 blocks, for parity checks