[Bug target/79487] Invalid _Decimal32 comparison on s390x

[vogt at linux dot vnet.ibm.com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=79487

--- Comment #14 from Dominik Vogt <vogt at linux dot vnet.ibm.com> ---
To me, it looks like the same bug does not happen with float just because there
is no need to convert this to 64 bit format for the comparison. 
simplify_const_unary_operation is not executed - if it was the same would have
happened for the float to double conversion.