The new graph structure replaces the node and edge linked lists with vectors.
Free lists (well, free vectors) are used for fast insertion/deletion.
The ultimate aim is to make PBQP graphs cheap to clone. The motivation is that
the PBQP solver destructively consumes input graphs while computing a solution,
forcing the graph to be fully reconstructed for each round of PBQP. This
imposes a high cost on large functions, which often require several rounds of
solving/spilling to find a final register allocation. If we can cheaply clone
the PBQP graph and incrementally update it between rounds then hopefully we can
reduce this cost. Further, once we begin pooling matrix/vector values (future
work), we can cache some PBQP solver metadata and share it between cloned
graphs, allowing the PBQP solver to re-use some of the computation done in
earlier rounds.
For now this is just a data structure update. The allocator and solver still
use the graph the same way as before, fully reconstructing it between each
round. I expect no material change from this update, although it may change
the iteration order of the nodes, causing ties in the solver to break in
different directions, and this could perturb the generated allocations
(hopefully in a completely benign way).
Thanks very much to Arnaud Allard de Grandmaison for encouraging me to get back
to work on this, and for a lot of discussion and many useful PBQP test cases.
llvm-svn: 194300
The idea of the AnyReg Calling Convention is to provide the call arguments in
registers, but not to force them to be placed in a paticular order into a
specified set of registers. Instead it is up tp the register allocator to assign
any register as it sees fit. The same applies to the return value (if
applicable).
Differential Revision: http://llvm-reviews.chandlerc.com/D2009
Reviewed by Andy
llvm-svn: 194293
On darwin, when trying to create compact unwind info, a .cfi_cfa_def
directive would case an llvm_unreachable() to be hit. Back off when we
see this directive and generate the regular DWARF style eh_frame.
rdar://15406518
llvm-svn: 194285
LoopUnswitch's code simplification routine has logic to convert conditional
branches into unconditional branches, after unswitching makes the condition
constant, and then remove any blocks that renders dead. Unfortunately, this
code is dead, currently broken, and furthermore, has never been alive (at least
as far back at 2006).
No functionality change intended.
llvm-svn: 194277
Based on discussions with Lang Hames and Jakob Stoklund Olesen at the hacker's lab, and in the light of upcoming work on the PBQP register allocator, it was though that CalcSpillWeights does not need to be a pass. This change will enable to customize / tune the spill weight computation depending on the allocator.
Update the documentation style while there.
No functionnal change.
llvm-svn: 194269
ARM prologues usually look like:
push {r7, lr}
sub sp, sp, #4
If code size is extremely important, this can be optimised to the single
instruction:
push {r6, r7, lr}
where we don't actually care about the contents of r6, but pushing it subtracts
4 from sp as a side effect.
This should implement such a conversion, predicated on the "minsize" function
attribute (-Oz) since I've yet to find any code it actually makes faster.
llvm-svn: 194264
Linux cannot open directories with open(2), although cygwin and *bsd can.
Motivation: The test, Object/directory.ll, had been failing with --target=cygwin on Linux. XFAIL was improper for host issues.
llvm-svn: 194257
Summary:
Consider a GEP of:
i8* getelementptr ({ [2 x i8], i32, i8, [3 x i8] }* @main.c, i32 0, i32 0, i64 0)
If we proceeded to GEP the aforementioned object by 8, would form a GEP of:
i8* getelementptr ({ [2 x i8], i32, i8, [3 x i8] }* @main.c, i32 0, i32 0, i64 8)
Note that we would go through the first array member, causing an
out-of-bounds accesses. This is problematic because we might get fooled
if we are trying to evaluate loads using this GEP, for example, based
off of an object with a constant initializer where the array is zero.
This fixes PR17732.
Reviewers: nicholas, chandlerc, void
Reviewed By: void
CC: llvm-commits, echristo, void, aemerson
Differential Revision: http://llvm-reviews.chandlerc.com/D2093
llvm-svn: 194220
The BlockAddress doesn't have access to the correct basic blocks until the
functions have been cloned. This causes the BlockAddress to point to the old
values. Just wait until the functions have been cloned before copying the
initializers.
PR13163
llvm-svn: 194218
of being converted and this path is not relevant to anything at this time
so I have just disabled it for a few days while I'm at the LLVM conference
and don't have time to complete it or properly fix it.
llvm-svn: 194201
after the 3.4 release to the release notes. See the *lengthy* llvmdev
and cfe-dev threads on this subject. There will be more emails,
discussion and announcements, but I want to make noise in as many places
as I can to get everyone's concerns voiced and understood.
llvm-svn: 194183
