target-arm: Return right result for Neon comparison with NaNs

Fix the helper functions implementing the Neon floating point comparison
ops (VCGE, VCGT, VCEQ, VACGT, VACGE) to return the right answer when
one of the values being compared is a NaN.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>

1 files changed, 18 insertions, 10 deletions

diff --git a/target-arm/neon_helper.c b/target-arm/neon_helper.c
index 2108664adc..9d54a75ef3 100644
--- a/target-arm/neon_helper.c
+++ b/target-arm/neon_helper.c
@@ -1810,32 +1810,40 @@ uint32_t HELPER(neon_mul_f32)(uint32_t a, uint32_t b)
 }
 
 /* Floating point comparisons produce an integer result.  */
-#define NEON_VOP_FCMP(name, cmp) \
+#define NEON_VOP_FCMP(name, ok) \
 uint32_t HELPER(neon_##name)(uint32_t a, uint32_t b) \
 { \
-    if (float32_compare_quiet(make_float32(a), make_float32(b), NFS) cmp 0) { \
-        return ~0; \
-    } else { \
-        return 0; \
+    switch (float32_compare_quiet(make_float32(a), make_float32(b), NFS)) { \
+    ok return ~0; \
+    default: return 0; \
     } \
 }
 
-NEON_VOP_FCMP(ceq_f32, ==)
-NEON_VOP_FCMP(cge_f32, >=)
-NEON_VOP_FCMP(cgt_f32, >)
+NEON_VOP_FCMP(ceq_f32, case float_relation_equal:)
+NEON_VOP_FCMP(cge_f32, case float_relation_equal: case float_relation_greater:)
+NEON_VOP_FCMP(cgt_f32, case float_relation_greater:)
 
 uint32_t HELPER(neon_acge_f32)(uint32_t a, uint32_t b)
 {
     float32 f0 = float32_abs(make_float32(a));
     float32 f1 = float32_abs(make_float32(b));
-    return (float32_compare_quiet(f0, f1,NFS) >= 0) ? ~0 : 0;
+    switch (float32_compare_quiet(f0, f1, NFS)) {
+    case float_relation_equal:
+    case float_relation_greater:
+        return ~0;
+    default:
+        return 0;
+    }
 }
 
 uint32_t HELPER(neon_acgt_f32)(uint32_t a, uint32_t b)
 {
     float32 f0 = float32_abs(make_float32(a));
     float32 f1 = float32_abs(make_float32(b));
-    return (float32_compare_quiet(f0, f1, NFS) > 0) ? ~0 : 0;
+    if (float32_compare_quiet(f0, f1, NFS) == float_relation_greater) {
+        return ~0;
+    }
+    return 0;
 }
 
 #define ELEM(V, N, SIZE) (((V) >> ((N) * (SIZE))) & ((1ull << (SIZE)) - 1))