varasm: check float size

In PR95226, the testcase was failing because we tried to output_constant a
NOP_EXPR to float from a double REAL_CST, and so we output a double where
the caller wanted a float.  That doesn't happen anymore, but with the
output_constant hunk we will ICE in that situation rather than emit the
wrong number of bytes.

Part of the problem was that initializer_constant_valid_p_1 returned true
for that NOP_EXPR, because it compared the sizes of integer types but not
floating-point types.  So the C++ front end assumed it didn't need to fold
the initializer.

	PR c++/95226

gcc/ChangeLog:

	* varasm.cc (output_constant) [REAL_TYPE]: Check that sizes match.
	(initializer_constant_valid_p_1): Compare float precision.

diff --git a/gcc/varasm.cc b/gcc/varasm.cc
index 571bb2e2f0eb293b917658d73beaf6e66675c26d..aee1affc57cacf6e1320c986a83249866049e566 100644 (file)
--- a/gcc/varasm.cc
+++ b/gcc/varasm.cc
@@ -4876,16 +4876,16 @@ initializer_constant_valid_p_1 (tree value, tree endtype, tree *cache)
        tree src_type = TREE_TYPE (src);
        tree dest_type = TREE_TYPE (value);
 
-       /* Allow conversions between pointer types, floating-point
-          types, and offset types.  */
+       /* Allow conversions between pointer types and offset types.  */
        if ((POINTER_TYPE_P (dest_type) && POINTER_TYPE_P (src_type))
-           || (FLOAT_TYPE_P (dest_type) && FLOAT_TYPE_P (src_type))
            || (TREE_CODE (dest_type) == OFFSET_TYPE
                && TREE_CODE (src_type) == OFFSET_TYPE))
          return initializer_constant_valid_p_1 (src, endtype, cache);
 
-       /* Allow length-preserving conversions between integer types.  */
-       if (INTEGRAL_TYPE_P (dest_type) && INTEGRAL_TYPE_P (src_type)
+       /* Allow length-preserving conversions between integer types and
+          floating-point types.  */
+       if (((INTEGRAL_TYPE_P (dest_type) && INTEGRAL_TYPE_P (src_type))
+            || (FLOAT_TYPE_P (dest_type) && FLOAT_TYPE_P (src_type)))
            && (TYPE_PRECISION (dest_type) == TYPE_PRECISION (src_type)))
          return initializer_constant_valid_p_1 (src, endtype, cache);
 
@@ -5255,6 +5255,7 @@ output_constant (tree exp, unsigned HOST_WIDE_INT size, unsigned int align,
       break;
 
     case REAL_TYPE:
+      gcc_assert (size == thissize);
       if (TREE_CODE (exp) != REAL_CST)
        error ("initializer for floating value is not a floating constant");
       else