[PATCH v3 1/6] bitint: Allow mode promotion of _BitInt types

[Yang Yujie]

For targets that treat small _BitInts like the fundamental
integral types, we should allow their machine modes to be promoted
in the same way.

gcc/ChangeLog:

        * explow.cc (promote_function_mode): Add a case for
        small/medium _BitInts.
        (promote_mode): Same.
---
 gcc/explow.cc | 24 ++++++++++++++++++++++++
 1 file changed, 24 insertions(+)

diff --git a/gcc/explow.cc b/gcc/explow.cc
index 7799a98053b..8f8ca7f011e 100644
--- a/gcc/explow.cc
+++ b/gcc/explow.cc
@@ -854,6 +854,18 @@ promote_function_mode (const_tree type, machine_mode mode, 
int *punsignedp,
 
   switch (TREE_CODE (type))
     {
+    case BITINT_TYPE:
+      if (TYPE_MODE (type) == BLKmode)
+       return mode;
+
+      struct bitint_info info;
+      bool ok;
+      ok = targetm.c.bitint_type_info (TYPE_PRECISION (type), &info);
+      gcc_assert (ok);
+
+      if (!info.extended)
+       return mode;
+      /* FALLTHRU */
     case INTEGER_TYPE:   case ENUMERAL_TYPE:   case BOOLEAN_TYPE:
     case REAL_TYPE:      case OFFSET_TYPE:     case FIXED_POINT_TYPE:
     case POINTER_TYPE:   case REFERENCE_TYPE:
@@ -893,6 +905,18 @@ promote_mode (const_tree type ATTRIBUTE_UNUSED, 
machine_mode mode,
 
   switch (code)
     {
+    case BITINT_TYPE:
+      if (TYPE_MODE (type) == BLKmode)
+       return mode;
+
+      struct bitint_info info;
+      bool ok;
+      ok = targetm.c.bitint_type_info (TYPE_PRECISION (type), &info);
+      gcc_assert (ok);
+
+      if (!info.extended)
+       return mode;
+      /* FALLTHRU */
     case INTEGER_TYPE:   case ENUMERAL_TYPE:   case BOOLEAN_TYPE:
     case REAL_TYPE:      case OFFSET_TYPE:     case FIXED_POINT_TYPE:
       /* Values of these types always have scalar mode.  */
-- 
2.46.0