[PULL 02/37] s390x/tcg: Fix FP CONVERT TO (LOGICAL) FIXED NaN handling

[Cornelia Huck <cohuck@redhat.com>]

From: David Hildenbrand <david@redhat.com>

In case we encounter a NaN, we have to return the smallest possible
number, corresponding to either 0 or the maximum negative number. This
seems to differ from IEEE handling as implemented in softfloat, whereby
we return the biggest possible number.

While at it, use float32_to_uint64() in the CLGEB handler.

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: David Hildenbrand <david@redhat.com>
Message-Id: <20210608092337.12221-2-david@redhat.com>
Signed-off-by: Cornelia Huck <cohuck@redhat.com>
---
 target/s390x/fpu_helper.c     | 41 +++++++++++++++++++++++++++++++----
 target/s390x/vec_fpu_helper.c |  8 +++++--
 2 files changed, 43 insertions(+), 6 deletions(-)

diff --git a/target/s390x/fpu_helper.c b/target/s390x/fpu_helper.c
index f155bc048c13..13af158748a9 100644
--- a/target/s390x/fpu_helper.c
+++ b/target/s390x/fpu_helper.c
@@ -509,6 +509,9 @@ uint64_t HELPER(cgeb)(CPUS390XState *env, uint64_t v2, uint32_t m34)
 
     s390_restore_bfp_rounding_mode(env, old_mode);
     handle_exceptions(env, xxc_from_m34(m34), GETPC());
+    if (float32_is_any_nan(v2)) {
+        return INT64_MIN;
+    }
     return ret;
 }
 
@@ -520,6 +523,9 @@ uint64_t HELPER(cgdb)(CPUS390XState *env, uint64_t v2, uint32_t m34)
 
     s390_restore_bfp_rounding_mode(env, old_mode);
     handle_exceptions(env, xxc_from_m34(m34), GETPC());
+    if (float64_is_any_nan(v2)) {
+        return INT64_MIN;
+    }
     return ret;
 }
 
@@ -532,6 +538,9 @@ uint64_t HELPER(cgxb)(CPUS390XState *env, uint64_t h, uint64_t l, uint32_t m34)
 
     s390_restore_bfp_rounding_mode(env, old_mode);
     handle_exceptions(env, xxc_from_m34(m34), GETPC());
+    if (float128_is_any_nan(v2)) {
+        return INT64_MIN;
+    }
     return ret;
 }
 
@@ -543,6 +552,9 @@ uint64_t HELPER(cfeb)(CPUS390XState *env, uint64_t v2, uint32_t m34)
 
     s390_restore_bfp_rounding_mode(env, old_mode);
     handle_exceptions(env, xxc_from_m34(m34), GETPC());
+    if (float32_is_any_nan(v2)) {
+        return INT32_MIN;
+    }
     return ret;
 }
 
@@ -554,6 +566,9 @@ uint64_t HELPER(cfdb)(CPUS390XState *env, uint64_t v2, uint32_t m34)
 
     s390_restore_bfp_rounding_mode(env, old_mode);
     handle_exceptions(env, xxc_from_m34(m34), GETPC());
+    if (float64_is_any_nan(v2)) {
+        return INT32_MIN;
+    }
     return ret;
 }
 
@@ -566,6 +581,9 @@ uint64_t HELPER(cfxb)(CPUS390XState *env, uint64_t h, uint64_t l, uint32_t m34)
 
     s390_restore_bfp_rounding_mode(env, old_mode);
     handle_exceptions(env, xxc_from_m34(m34), GETPC());
+    if (float128_is_any_nan(v2)) {
+        return INT32_MIN;
+    }
     return ret;
 }
 
@@ -573,12 +591,12 @@ uint64_t HELPER(cfxb)(CPUS390XState *env, uint64_t h, uint64_t l, uint32_t m34)
 uint64_t HELPER(clgeb)(CPUS390XState *env, uint64_t v2, uint32_t m34)
 {
     int old_mode = s390_swap_bfp_rounding_mode(env, round_from_m34(m34));
-    uint64_t ret;
-
-    v2 = float32_to_float64(v2, &env->fpu_status);
-    ret = float64_to_uint64(v2, &env->fpu_status);
+    uint64_t ret = float32_to_uint64(v2, &env->fpu_status);
     s390_restore_bfp_rounding_mode(env, old_mode);
     handle_exceptions(env, xxc_from_m34(m34), GETPC());
+    if (float32_is_any_nan(v2)) {
+        return 0;
+    }
     return ret;
 }
 
@@ -590,6 +608,9 @@ uint64_t HELPER(clgdb)(CPUS390XState *env, uint64_t v2, uint32_t m34)
 
     s390_restore_bfp_rounding_mode(env, old_mode);
     handle_exceptions(env, xxc_from_m34(m34), GETPC());
+    if (float64_is_any_nan(v2)) {
+        return 0;
+    }
     return ret;
 }
 
@@ -601,6 +622,9 @@ uint64_t HELPER(clgxb)(CPUS390XState *env, uint64_t h, uint64_t l, uint32_t m34)
 
     s390_restore_bfp_rounding_mode(env, old_mode);
     handle_exceptions(env, xxc_from_m34(m34), GETPC());
+    if (float128_is_any_nan(make_float128(h, l))) {
+        return 0;
+    }
     return ret;
 }
 
@@ -612,6 +636,9 @@ uint64_t HELPER(clfeb)(CPUS390XState *env, uint64_t v2, uint32_t m34)
 
     s390_restore_bfp_rounding_mode(env, old_mode);
     handle_exceptions(env, xxc_from_m34(m34), GETPC());
+    if (float32_is_any_nan(v2)) {
+        return 0;
+    }
     return ret;
 }
 
@@ -623,6 +650,9 @@ uint64_t HELPER(clfdb)(CPUS390XState *env, uint64_t v2, uint32_t m34)
 
     s390_restore_bfp_rounding_mode(env, old_mode);
     handle_exceptions(env, xxc_from_m34(m34), GETPC());
+    if (float64_is_any_nan(v2)) {
+        return 0;
+    }
     return ret;
 }
 
@@ -634,6 +664,9 @@ uint64_t HELPER(clfxb)(CPUS390XState *env, uint64_t h, uint64_t l, uint32_t m34)
 
     s390_restore_bfp_rounding_mode(env, old_mode);
     handle_exceptions(env, xxc_from_m34(m34), GETPC());
+    if (float128_is_any_nan(make_float128(h, l))) {
+        return 0;
+    }
     return ret;
 }
 
diff --git a/target/s390x/vec_fpu_helper.c b/target/s390x/vec_fpu_helper.c
index c1564e819b19..56765918d204 100644
--- a/target/s390x/vec_fpu_helper.c
+++ b/target/s390x/vec_fpu_helper.c
@@ -326,7 +326,9 @@ void HELPER(gvec_vcdlg64s)(void *v1, const void *v2, CPUS390XState *env,
 
 static uint64_t vcgd64(uint64_t a, float_status *s)
 {
-    return float64_to_int64(a, s);
+    const uint64_t tmp = float64_to_int64(a, s);
+
+    return float64_is_any_nan(a) ? INT64_MIN : tmp;
 }
 
 void HELPER(gvec_vcgd64)(void *v1, const void *v2, CPUS390XState *env,
@@ -349,7 +351,9 @@ void HELPER(gvec_vcgd64s)(void *v1, const void *v2, CPUS390XState *env,
 
 static uint64_t vclgd64(uint64_t a, float_status *s)
 {
-    return float64_to_uint64(a, s);
+    const uint64_t tmp = float64_to_uint64(a, s);
+
+    return float64_is_any_nan(a) ? 0 : tmp;
 }
 
 void HELPER(gvec_vclgd64)(void *v1, const void *v2, CPUS390XState *env,
-- 
2.31.1