target/arm: Simplify pstate_sm check in sve_access_check

In StreamingMode, fp_access_checked is handled already.
We cannot fall through to fp_access_check lest we fall
foul of the double-check assertion.

Cc: qemu-stable@nongnu.org
Fixes: 285b1d5fcef ("target/arm: Handle SME in sve_access_check")
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20250307190415.982049-3-richard.henderson@linaro.org
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
[PMM: move declaration of 'ret' to top of block]
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

target/arm/tcg/translate-a64.c

@@ -1456,23 +1456,23 @@ static int fp_access_check_vector_hsd(DisasContext *s, bool is_q, MemOp esz)
 bool sve_access_check(DisasContext *s)
 {
     if (s->pstate_sm || !dc_isar_feature(aa64_sve, s)) {
+        bool ret;
+
         assert(dc_isar_feature(aa64_sme, s));
-        if (!sme_sm_enabled_check(s)) {
-            goto fail_exit;
-        }
-    } else if (s->sve_excp_el) {
+        ret = sme_sm_enabled_check(s);
+        s->sve_access_checked = (ret ? 1 : -1);
+        return ret;
+    }
+    if (s->sve_excp_el) {
+        /* Assert that we only raise one exception per instruction. */
+        assert(!s->sve_access_checked);
         gen_exception_insn_el(s, 0, EXCP_UDEF,
                               syn_sve_access_trap(), s->sve_excp_el);
-        goto fail_exit;
+        s->sve_access_checked = -1;
+        return false;
     }
     s->sve_access_checked = 1;
     return fp_access_check(s);
-
- fail_exit:
-    /* Assert that we only raise one exception per instruction. */
-    assert(!s->sve_access_checked);
-    s->sve_access_checked = -1;
-    return false;
 }
 
 /*