[Bug ada/26797] [4.3 regression] ACATS cxh1001 fails

[kenner at vlsi1 dot ultra dot nyu dot edu]

------- Comment #26 from kenner at vlsi1 dot ultra dot nyu dot edu  2007-03-08 12:54 -------
Subject: Re:  [4.3 regression] ACATS cxh1001 fails

> y = __builtin_nop(x); valid = (y>=lower_bound && y <=upper_bound);
> The point is that the intrinsic would be opaque to the optimizers,
> and would only be lowered to the identity function *after* the tree
> optimizers have run.  One annoyance is that presumably intrinsics
> would be needed for all integer and float precisions, eg
> __builtin_nop8, __builtin_nop16, etc.

More than each precision.  The VIEW_CONVERT_EXPR is to the base type
and there can be an unlimited number of them for each precision.

Because it has to work with arbitrary types, a builtin won't do it.
We could certainly add a new tree expression that says "don't look through
this for VRP purposes", but we already have V_C_E.


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=26797