Re: [PATCH v8 1/1] target/riscv: rvv: Use wider accesses for unit stride load/store

[Richard Henderson]

On 1/8/25 06:35, Craig Blackmore wrote:

+GEN_VEXT_LDST_ATOMIC_HOST(2, uint16_t)
+GEN_VEXT_LDST_ATOMIC_HOST(4, uint32_t)
+#ifdef CONFIG_ATOMIC64
+GEN_VEXT_LDST_ATOMIC_HOST(8, uint64_t)
+#endif

...

+    /*
+     * If !HAVE_ATOMIC128_RO, then atomic16_set may be implemented with a
+     * 16-byte compare and store loop, which is expensive, so prefer two 8-byte
+     * stores in this case.
+     */
+    if (HAVE_ATOMIC128_RO && (is_load || HAVE_ATOMIC128_RW)
+        && (test % 16 == 0)) {
+        for (; reg_start < evl; reg_start += 16 >> log2_esz, host += 16) {
+            vext_ldst_atom_16_host(vd, reg_start * esz, host, is_load);
+        }
+        return;
+    }
+    if (test % 8 == 0) {
+        for (; reg_start < evl; reg_start += 8 >> log2_esz, host += 8) {
+            vext_ldst_atom_8_host(vd, reg_start * esz, host, is_load);
+        }
+        return;
+    }

You need ifdef CONFIG_ATOMIC64 around this block.


r~

+    if (test % 4 == 0) {
+        for (; reg_start < evl; reg_start += 4 >> log2_esz, host += 4) {
+            vext_ldst_atom_4_host(vd, reg_start * esz, host, is_load);
          }
+        return;
+    }
+    if (test % 2 == 0) {
+        for (; reg_start < evl; reg_start += 2 >> log2_esz, host += 2) {
+            vext_ldst_atom_2_host(vd, reg_start * esz, host, is_load);
+        }
+        return;
      }
+    g_assert_not_reached();