softfloat: Pad array size in pick_nan_muladd

While all indices into val[] should be in [0-2], the mask
applied is two bits.  To help static analysis see there is
no possibility of read beyond the end of the array, pad the
array to 4 entries, with the final being (implicitly) NULL.

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Message-id: 20241203203949.483774-6-richard.henderson@linaro.org
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

diff --git a/fpu/softfloat-parts.c.inc b/fpu/softfloat-parts.c.inc
index 525db617411a37395185f45a226dae5f8ac1c278..5fcdbc87fd74363ca048d3389a951a0846f91659 100644 (file)
--- a/fpu/softfloat-parts.c.inc
+++ b/fpu/softfloat-parts.c.inc
@@ -106,7 +106,7 @@ static FloatPartsN *partsN(pick_nan_muladd)(FloatPartsN *a, FloatPartsN *b,
         }
         ret = c;
     } else {
-        FloatPartsN *val[3] = { a, b, c };
+        FloatPartsN *val[R_3NAN_1ST_MASK + 1] = { a, b, c };
         Float3NaNPropRule rule = s->float_3nan_prop_rule;
 
         assert(rule != float_3nan_prop_none);