[10/11] softfloat: Sink frac_cmp in parts_pick_nan until needed

Commit Message

Richard Henderson Dec. 3, 2024, 8:39 p.m. UTC

Move the fractional comparison to the end of the
float_2nan_prop_x87 case.  This is not required for
any other 2nan propagation rule.  Reorganize the
x87 case itself to break out of the switch when the
fractional comparison is not required.

Signed-off-by: Richard Henderson <[e-mail]>
---
 fpu/softfloat-parts.c.inc | 19 +++++++++----------
 1 file changed, 9 insertions(+), 10 deletions(-)

Patch

diff --git a/fpu/softfloat-parts.c.inc b/fpu/softfloat-parts.c.inc
index 099f1c48ef..9a2287095c 100644
--- a/fpu/softfloat-parts.c.inc
+++ b/fpu/softfloat-parts.c.inc
@@ -52,11 +52,6 @@  static FloatPartsN *partsN(pick_nan)(FloatPartsN *a, FloatPartsN *b,
         return a;
     }
 
-    cmp = frac_cmp(a, b);
-    if (cmp == 0) {
-        cmp = a->sign < b->sign;
-    }
-
     switch (s->float_2nan_prop_rule) {
     case float_2nan_prop_s_ab:
         if (have_snan) {
@@ -89,20 +84,24 @@  static FloatPartsN *partsN(pick_nan)(FloatPartsN *a, FloatPartsN *b,
          * return the NaN with the positive sign bit (if any).
          */
         if (is_snan(a->cls)) {
-            if (is_snan(b->cls)) {
-                which = cmp > 0 ? 0 : 1;
-            } else {
+            if (!is_snan(b->cls)) {
                 which = is_qnan(b->cls) ? 1 : 0;
+                break;
             }
         } else if (is_qnan(a->cls)) {
             if (is_snan(b->cls) || !is_qnan(b->cls)) {
                 which = 0;
-            } else {
-                which = cmp > 0 ? 0 : 1;
+                break;
             }
         } else {
             which = 1;
+            break;
         }
+        cmp = frac_cmp(a, b);
+        if (cmp == 0) {
+            cmp = a->sign < b->sign;
+        }
+        which = cmp > 0 ? 0 : 1;
         break;
     default:
         g_assert_not_reached();