http://gcc.gnu.org/bugzilla/show_bug.cgi?id=56094
Bug #: 56094
Summary: Invalid line number info generated with tree-level
ivopts
Classification: Unclassified
Product: gcc
Version: 4.8.0
Status: UNCONFIRMED
Severity: minor
Priority: P3
Component: tree-optimization
AssignedTo: unassig...@gcc.gnu.org
ReportedBy: josh.m.con...@gmail.com
The attached code has a number of instructions that are associated with the
head of the function. This was showing up when setting a breakpoint on the
function itself and gdb was setting several - not a problem in general, except
that the statements were more appropriately correlated with intra-loop
calculations instead of anything to do with the prologue.
To reproduce, compile the attached file with -g -O2, and notice the statements
associated with line 83.
These lines are in fact statements that are generated during tree-level
induction variable optimization, but which aren't getting their location data
copied over from the gimple statement and so they default to the start of the
function (sorry for being a bit vague, but it's been a while since I looked
into the mechanics of this and I don't recall the details).
The fix I have implemented in our local tree is in rewrite_use_nonlinear_expr,
where after generating the computation (comp) I verify that it has a location
associated with it - if it doesn't but the use stmt (use->stmt) does have a
location, I copy the location from the use->stmt over to comp.
