no noalias not negligible - a difference between C and Fortran - long

Tim Olson tim at amdcad.AMD.COM
Tue May 24 02:34:21 AEST 1988


In article <7879 at alice.UUCP> ark at alice.UUCP writes:
| I don't really think there's much here that noalias would help:
| the object code has to fetch dy[i], add da, multiply by
| dx[i], and store it in dy[i] and aliasing is irrelevant to
| each of these operations.

But that forces each iteration of the loop to be performed sequentially.
I believe the original intent was to guarantee non-overlapping arrays to
allow vector machines to compute the loop iterations in parallel.

	-- Tim Olson
	Advanced Micro Devices
	(tim at amdcad.amd.com)



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