This is a suggestion from item 108 of the "old PROBLEMS" file that
actually still makes a lot of sense, for a change:
----------------------------------------
Can speed up flow analysis by making a table saying
which register is set and which registers are used by each instruction
that only sets one register and only uses two. This way avoid the
tree walk for such instructions (most instructions).
----------------------------------------
As it is now, we actually have this - sometimes. The above is how we
compute liveness in df.c, and indeed it would be nice to unify these
parts of flow.c and df.c that are basically duplicating code. Liveness
is computed quite a few times in the RTL path, so speeding it up is a
Good Thing.
--
Summary: Suggestion for speeding up data flow analysis
Product: gcc
Version: unknown
Status: UNCONFIRMED
Severity: enhancement
Priority: P2
Component: middle-end
AssignedTo: unassigned at gcc dot gnu dot org
ReportedBy: steven at gcc dot gnu dot org
CC: gcc-bugs at gcc dot gnu dot org
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=19207
