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Fix code generation error in gcc6809
It turned out that under some circumstances, the gcc optimizer would select
an instruction sequence that had the sense of a branch inverted. It seems
this was due to a particular instruction pattern included in the machine
description not being quite right with respect to how the condition codes
were tracked. Removing that instruction pattern seems to fix things
(subtraction with the arguments reversed). gcc seems to be smart enough to
figure out how to reorganize code to work without this reversed sense
subtraction and then do the right thing.
author | William Astle <lost@l-w.ca> |
---|---|
date | Thu, 24 Mar 2016 20:07:20 -0600 |
parents | e95f07cbce4e |
children |
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