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Re: Several C++ regressions
On Aug 23, 2004, at 10:12 AM, Zack Weinberg wrote:
Diego Novillo <dnovillo@redhat.com> writes:
On Mon, 2004-08-23 at 12:39, Andrew Pinski wrote:
OK? Tested on powerpc-apple-darwin, this time with no regressions
and it fixes the regressions that were caused by my first patch.
I would rather back out the original patch to give you time to
investigate the real problem. There may be other nasties lurking
around.
Mark and I concur. This is an optimization -- I know it works around
some codegen bugs, but it doesn't fix the underlying problems with the
alias analyzer -- so, since it breaks stuff, let's back it out and try
again.
I finally figured out what was going on, the patch which I posted was
the right fix but was not able to detect cases where it was safe to
just build &a->b like when there was only one base class and such.
This new one patch always the C++ front-end to keep those in this form
and not lower then until later.
I should note that C++ front-end does the conversion to the base classes
where there need to be code in a subroutine of convert which is why the
generated code was wrong.
OK? Tested on powerpc-apple-darwin and this time no regressions.
Thanks,
Andrew Pinski
ChangeLog:
* typeck.c (build_unary_op): Keep &a->b form when we can keep it.
Index: typeck.c
===================================================================
RCS file: /cvs/gcc/gcc/gcc/cp/typeck.c,v
retrieving revision 1.569
diff -u -p -r1.569 typeck.c
--- typeck.c 23 Aug 2004 18:24:18 -0000 1.569
+++ typeck.c 23 Aug 2004 22:42:00 -0000
@@ -4123,6 +4123,15 @@ build_unary_op (enum tree_code code, tre
addr = fold (build2 (PLUS_EXPR, argtype, rval,
cp_convert (argtype,
byte_position (field))));
+
+ /* If the folded PLUS_EXPR is not a constant address, wrap
+ it in an ADDR_EXPR unless we have a base class and we
require
+ code to convert to the base class. */
+ if (!TREE_CONSTANT (addr)
+ && (!DECL_ARTIFICIAL (field)
+ || !TYPE_BASE_CONVS_MAY_REQUIRE_CODE_P
+ (TREE_TYPE (TREE_OPERAND (arg, 0)))))
+ addr = build_address (arg);
}
if (TREE_CODE (argtype) == POINTER_TYPE