[Bug tree-optimization/21173] [4.0/4.1 regression] miscompiled pointer subtraction broke Linux kernel

[stevenb at suse dot de]

------- Additional Comments From stevenb at suse dot de  2005-04-23 23:01 -------
Subject: Re:  [4.0/4.1 regression] miscompiled pointer subtraction broke Linux kernel

Yeah, well, ehm...

The original bug resurfaces with my patch.  This happens because
is_gimple_reg_rhs only looks at the outermost level of the expression,
e.g. it happily accepts "(intD.0) -xD.1566_4" as a valid GIMPLE rhs.

Obviously this is wrong.

I'm testing a new patch that simply always runs force_gimple_operand
on folded, it's not clear to me why we don't do that anyway (it is
cheap and safer).



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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=21173