[PULL 026/101] softfloat: Add flag specific to signaling nans

[Cédric Le Goater]

From: Richard Henderson <richard.henderson@linaro.org>

PowerPC has this flag, and it's easier to compute it here
than after the fact.

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20211119160502.17432-8-richard.henderson@linaro.org>
Signed-off-by: Cédric Le Goater <clg@kaod.org>
---
 include/fpu/softfloat-types.h |  1 +
 fpu/softfloat.c               |  4 +++-
 fpu/softfloat-parts.c.inc     | 18 ++++++++++++------
 3 files changed, 16 insertions(+), 7 deletions(-)

diff --git a/include/fpu/softfloat-types.h b/include/fpu/softfloat-types.h
index 9ca50e930b8d..8abd9ab4ec9c 100644
--- a/include/fpu/softfloat-types.h
+++ b/include/fpu/softfloat-types.h
@@ -158,6 +158,7 @@ enum {
     float_flag_invalid_zdz     = 0x0400,  /* 0 / 0 */
     float_flag_invalid_sqrt    = 0x0800,  /* sqrt(-x) */
     float_flag_invalid_cvti    = 0x1000,  /* non-nan to integer */
+    float_flag_invalid_snan    = 0x2000,  /* any operand was snan */
 };
 
 /*
diff --git a/fpu/softfloat.c b/fpu/softfloat.c
index 9a28720d82a5..834ed3a054f7 100644
--- a/fpu/softfloat.c
+++ b/fpu/softfloat.c
@@ -2543,8 +2543,10 @@ floatx80 floatx80_mod(floatx80 a, floatx80 b, 
float_status *status)
 static void parts_float_to_ahp(FloatParts64 *a, float_status *s)
 {
     switch (a->cls) {
-    case float_class_qnan:
     case float_class_snan:
+        float_raise(float_flag_invalid_snan, s);
+        /* fall through */
+    case float_class_qnan:
         /*
          * There is no NaN in the destination format.  Raise Invalid
          * and return a zero with the sign of the input NaN.
diff --git a/fpu/softfloat-parts.c.inc b/fpu/softfloat-parts.c.inc
index ce580347dda6..db3e1f393dfb 100644
--- a/fpu/softfloat-parts.c.inc
+++ b/fpu/softfloat-parts.c.inc
@@ -19,7 +19,7 @@ static void partsN(return_nan)(FloatPartsN *a, float_status 
*s)
 {
     switch (a->cls) {
     case float_class_snan:
-        float_raise(float_flag_invalid, s);
+        float_raise(float_flag_invalid | float_flag_invalid_snan, s);
         if (s->default_nan_mode) {
             parts_default_nan(a, s);
         } else {
@@ -40,7 +40,7 @@ static FloatPartsN *partsN(pick_nan)(FloatPartsN *a, 
FloatPartsN *b,
                                      float_status *s)
 {
     if (is_snan(a->cls) || is_snan(b->cls)) {
-        float_raise(float_flag_invalid, s);
+        float_raise(float_flag_invalid | float_flag_invalid_snan, s);
     }
 
     if (s->default_nan_mode) {
@@ -68,7 +68,7 @@ static FloatPartsN *partsN(pick_nan_muladd)(FloatPartsN *a, 
FloatPartsN *b,
     int which;
 
     if (unlikely(abc_mask & float_cmask_snan)) {
-        float_raise(float_flag_invalid, s);
+        float_raise(float_flag_invalid | float_flag_invalid_snan, s);
     }
 
     which = pickNaNMulAdd(a->cls, b->cls, c->cls,
@@ -1049,8 +1049,10 @@ static int64_t partsN(float_to_sint)(FloatPartsN *p, 
FloatRoundMode rmode,
 
     switch (p->cls) {
     case float_class_snan:
+        flags |= float_flag_invalid_snan;
+        /* fall through */
     case float_class_qnan:
-        flags = float_flag_invalid;
+        flags |= float_flag_invalid;
         r = max;
         break;
 
@@ -1114,8 +1116,10 @@ static uint64_t partsN(float_to_uint)(FloatPartsN *p, 
FloatRoundMode rmode,
 
     switch (p->cls) {
     case float_class_snan:
+        flags |= float_flag_invalid_snan;
+        /* fall through */
     case float_class_qnan:
-        flags = float_flag_invalid;
+        flags |= float_flag_invalid;
         r = max;
         break;
 
@@ -1341,7 +1345,9 @@ static FloatRelation partsN(compare)(FloatPartsN *a, 
FloatPartsN *b,
     }
 
     if (unlikely(ab_mask & float_cmask_anynan)) {
-        if (!is_quiet || (ab_mask & float_cmask_snan)) {
+        if (ab_mask & float_cmask_snan) {
+            float_raise(float_flag_invalid | float_flag_invalid_snan, s);
+        } else if (!is_quiet) {
             float_raise(float_flag_invalid, s);
         }
         return float_relation_unordered;
-- 
2.31.1