Commit 1649553313 for qemu.org

commit 16495533131af2eb94019e32c72688ea5e1b2742
Author: Richard Henderson <richard.henderson@linaro.org>
Date:   Wed Apr 29 04:32:49 2026 +1000

    host-utils: Introduce signed saturation primitives

    Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
    Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

diff --git a/accel/tcg/tcg-runtime-gvec.c b/accel/tcg/tcg-runtime-gvec.c
index ff927c5dd8..67a741e45e 100644
--- a/accel/tcg/tcg-runtime-gvec.c
+++ b/accel/tcg/tcg-runtime-gvec.c
@@ -1109,10 +1109,7 @@ void HELPER(gvec_ssadd32)(void *d, void *a, void *b, uint32_t desc)
     for (i = 0; i < oprsz; i += sizeof(int32_t)) {
         int32_t ai = *(int32_t *)(a + i);
         int32_t bi = *(int32_t *)(b + i);
-        int32_t di;
-        if (sadd32_overflow(ai, bi, &di)) {
-            di = (di < 0 ? INT32_MAX : INT32_MIN);
-        }
+        int32_t di = sadd32_saturate(ai, bi);
         *(int32_t *)(d + i) = di;
     }
     clear_high(d, oprsz, desc);
@@ -1126,10 +1123,7 @@ void HELPER(gvec_ssadd64)(void *d, void *a, void *b, uint32_t desc)
     for (i = 0; i < oprsz; i += sizeof(int64_t)) {
         int64_t ai = *(int64_t *)(a + i);
         int64_t bi = *(int64_t *)(b + i);
-        int64_t di;
-        if (sadd64_overflow(ai, bi, &di)) {
-            di = (di < 0 ? INT64_MAX : INT64_MIN);
-        }
+        int64_t di = sadd64_saturate(ai, bi);
         *(int64_t *)(d + i) = di;
     }
     clear_high(d, oprsz, desc);
@@ -1177,10 +1171,7 @@ void HELPER(gvec_sssub32)(void *d, void *a, void *b, uint32_t desc)
     for (i = 0; i < oprsz; i += sizeof(int32_t)) {
         int32_t ai = *(int32_t *)(a + i);
         int32_t bi = *(int32_t *)(b + i);
-        int32_t di;
-        if (ssub32_overflow(ai, bi, &di)) {
-            di = (di < 0 ? INT32_MAX : INT32_MIN);
-        }
+        int32_t di = ssub32_saturate(ai, bi);
         *(int32_t *)(d + i) = di;
     }
     clear_high(d, oprsz, desc);
@@ -1194,10 +1185,7 @@ void HELPER(gvec_sssub64)(void *d, void *a, void *b, uint32_t desc)
     for (i = 0; i < oprsz; i += sizeof(int64_t)) {
         int64_t ai = *(int64_t *)(a + i);
         int64_t bi = *(int64_t *)(b + i);
-        int64_t di;
-        if (ssub64_overflow(ai, bi, &di)) {
-            di = (di < 0 ? INT64_MAX : INT64_MIN);
-        }
+        int64_t di = ssub64_saturate(ai, bi);
         *(int64_t *)(d + i) = di;
     }
     clear_high(d, oprsz, desc);
diff --git a/include/qemu/host-utils.h b/include/qemu/host-utils.h
index 181d026b6c..2e8da7fb3d 100644
--- a/include/qemu/host-utils.h
+++ b/include/qemu/host-utils.h
@@ -606,6 +606,66 @@ static inline bool umul64_overflow(uint64_t x, uint64_t y, uint64_t *ret)
     return __builtin_mul_overflow(x, y, ret);
 }

+/**
+ * sadd32_saturate - addition with saturation
+ * @x, @y: addends
+ *
+ * Computes @x + @y, and saturates rathern than truncating the result.
+ */
+static inline int32_t sadd32_saturate(int32_t x, int32_t y)
+{
+    int32_t ret;
+    if (sadd32_overflow(x, y, &ret)) {
+        ret = y < 0 ? INT32_MIN : INT32_MAX;
+    }
+    return ret;
+}
+
+/**
+ * sadd64_saturate - addition with saturation
+ * @x, @y: addends
+ *
+ * Computes @x + @y, and saturates rathern than truncating the result.
+ */
+static inline int64_t sadd64_saturate(int64_t x, int64_t y)
+{
+    int64_t ret;
+    if (sadd64_overflow(x, y, &ret)) {
+        ret = y < 0 ? INT64_MIN : INT64_MAX;
+    }
+    return ret;
+}
+
+/**
+ * ssub32_saturate - subtraction with saturation
+ * @x, @y: addends
+ *
+ * Computes @x + @y, and saturates rathern than truncating the result.
+ */
+static inline bool ssub32_saturate(int32_t x, int32_t y)
+{
+    int32_t ret;
+    if (ssub32_overflow(x, y, &ret)) {
+        ret = x < 0 ? INT32_MAX : INT32_MIN;
+    }
+    return ret;
+}
+
+/**
+ * ssub64_saturate - subtraction with saturation
+ * @x, @y: addends
+ *
+ * Computes @x + @y, and saturates rathern than truncating the result.
+ */
+static inline bool ssub64_saturate(int64_t x, int64_t y)
+{
+    int64_t ret;
+    if (ssub64_overflow(x, y, &ret)) {
+        ret = x < 0 ? INT64_MAX : INT64_MIN;
+    }
+    return ret;
+}
+
 /*
  * Unsigned 128x64 multiplication.
  * Returns true if the result got truncated to 128 bits.