[Bug target/42894] [4.5 Regression] Invalid rtl sharing in Thumb1.

[rearnsha at gcc dot gnu dot org]

------- Comment #9 from rearnsha at gcc dot gnu dot org  2010-02-24 11:15 -------
I think the real problem here is that shared_const_p thinks that _this_ const
expression can't be shared (though I can't see any reason why it couldn't).

The comment in that function says, "CONST can be shared if it contains a
SYMBOL_REF.  If it contains a LABEL_REF, it isn't sharable", but it then
proceeds to check only that the expression is sym+const_int and assumes all
other cases are non-shareable.  That's really too restrictive.  A better check
would be that the expression contains no 'label-ref' node.

However, there might be some other port that relies on the existing
behaviour...


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=42894