From b333b06772c89d96aacb5490d6a219fba7c09cc6 Mon Sep 17 00:00:00 2001
From: Mitja Felicijan <mitja.felicijan@gmail.com>
Date: Thu, 12 Feb 2026 20:57:17 +0100
Subject: Engage!

---
 llama.cpp/tests/test-double-float.cpp | 57 +++++++++++++++++++++++++++++++++++
 1 file changed, 57 insertions(+)
 create mode 100644 llama.cpp/tests/test-double-float.cpp

(limited to 'llama.cpp/tests/test-double-float.cpp')

diff --git a/llama.cpp/tests/test-double-float.cpp b/llama.cpp/tests/test-double-float.cpp
new file mode 100644
index 0000000..6aac473
--- /dev/null
+++ b/llama.cpp/tests/test-double-float.cpp
@@ -0,0 +1,57 @@
+// These tests may take a long time!
+// They are to prove that conversion from double to float of various functions in ggml.c doesn't affect the result.
+// This is done by checking all finite (non-NaN, non-infinite) floats.
+
+#undef NDEBUG
+#include <cassert>
+#if !defined(__riscv) && !defined(__s390__) && !defined(__ARM_NEON)
+#include <immintrin.h>
+#endif
+#include <cmath>
+#include <cstdint>
+#include <cstring>
+
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wdouble-promotion"
+
+// ggml.c::quantize_row_q4_0_ref
+inline static uint8_t round_orig(float v0) { return ((int8_t) (round(v0))) + 8; }
+
+// ggml.c::ggml_silu_f32
+inline static float silu_orig(float x) {
+    return x/(1.0 + exp(-x));
+}
+
+#pragma GCC diagnostic pop
+
+// ggml.c::quantize_row_q4_0_ref
+inline static uint8_t round_float(float v0) { return (int8_t)roundf(v0) + 8; }
+
+// ggml.c::ggml_silu_f32
+inline static float silu_float(float x) {
+    return x/(1.0f + expf(-x));
+}
+
+int main(void) {
+    uint32_t x = UINT32_MAX;
+    do {
+        float f;
+        memcpy(&f, &x, sizeof(x));
+        assert(!std::isfinite(f) || (round_orig(f) == round_float(f)));
+    } while (x--);
+
+#ifdef __F16C__
+    // GELU and SILU implementations are used with a FP16 lookup table.
+    // The original and float-only results are not equal for all inputs after converting to FP16.
+    // GELU is an approximation anyway (tanh), not tested here.
+    // For SILU, verify that the results are at least the closest floating point numbers, if the FP16 values don't match.
+    for (x = 0; x <= UINT16_MAX; x++) {
+        float f = _cvtsh_ss(x);
+        const float so = silu_orig(f);
+        const float sf = silu_float(f);
+        assert(   (_cvtss_sh(so, 0) == _cvtss_sh(sf, 0))
+               || (nextafterf(so, sf) == sf)
+               || (nextafterf(sf, so) == so));
+    }
+#endif
+}
-- 
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