target/s390x: fix handling of zeroes in vfmin/vfmax

vfmin_res() / vfmax_res() are trying to check whether a and b are both
zeroes, but in reality they check that they are the same kind of zero.
This causes incorrect results when comparing positive and negative
zeroes.

Fixes: da4807527f3b ("s390x/tcg: Implement VECTOR FP (MAXIMUM|MINIMUM)")
Co-developed-by: Ulrich Weigand <ulrich.weigand@de.ibm.com>
Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: David Hildenbrand <david@redhat.com>
Message-Id: <20220713182612.3780050-2-iii@linux.ibm.com>
Signed-off-by: Thomas Huth <thuth@redhat.com>

diff --git a/target/s390x/tcg/vec_fpu_helper.c b/target/s390x/tcg/vec_fpu_helper.c
index 2a618a10935f353fd53357da2b4b9d8d77aecc58..75cf605b9f4cdc93d5ce2c2aaf3f62b8875f03e1 100644 (file)
--- a/target/s390x/tcg/vec_fpu_helper.c
+++ b/target/s390x/tcg/vec_fpu_helper.c
@@ -824,7 +824,7 @@ static S390MinMaxRes vfmin_res(uint16_t dcmask_a, uint16_t dcmask_b,
         default:
             g_assert_not_reached();
         }
-    } else if (unlikely(dcmask_a & dcmask_b & DCMASK_ZERO)) {
+    } else if (unlikely((dcmask_a & DCMASK_ZERO) && (dcmask_b & DCMASK_ZERO))) {
         switch (type) {
         case S390_MINMAX_TYPE_JAVA:
             return neg_a ? S390_MINMAX_RES_A : S390_MINMAX_RES_B;
@@ -874,7 +874,7 @@ static S390MinMaxRes vfmax_res(uint16_t dcmask_a, uint16_t dcmask_b,
         default:
             g_assert_not_reached();
         }
-    } else if (unlikely(dcmask_a & dcmask_b & DCMASK_ZERO)) {
+    } else if (unlikely((dcmask_a & DCMASK_ZERO) && (dcmask_b & DCMASK_ZERO))) {
         const bool neg_a = dcmask_a & DCMASK_NEGATIVE;
 
         switch (type) {