The common code in the post-RA scheduler to break anti-dependencies on the
critical path contained a flaw. In the reported case, an anti-dependency
between the overlapping registers %X4 and %R4 exists:
%X29<def> = OR8 %X4, %X4
%R4<def>, %X3<def,dead,tied3> = LBZU 1, %X3<kill,tied1>
The unpatched code breaks the dependency by replacing %R4 and its uses
with %R3, the first register on the available list. However, %R3 and
%X3 overlap, so this creates two overlapping definitions on the same
instruction.
The fix is straightforward, preventing selection of a register that
overlaps any other defined register on the same instruction.
The test case is reduced from the bug report, and verifies that we no
longer produce "lbzu 3, 1(3)" when breaking this anti-dependency.
llvm-svn: 173706
Sooooo many of these had incorrect or strange main module includes.
I have manually inspected all of these, and fixed the main module
include to be the nearest plausible thing I could find. If you own or
care about any of these source files, I encourage you to take some time
and check that these edits were sensible. I can't have broken anything
(I strictly added headers, and reordered them, never removed), but they
may not be the headers you'd really like to identify as containing the
API being implemented.
Many forward declarations and missing includes were added to a header
files to allow them to parse cleanly when included first. The main
module rule does in fact have its merits. =]
llvm-svn: 169131
No functional change intended.
Sorry for the churn. The iterator classes are supposed to help avoid
giant commits like this one in the future. The TableGen-produced
register lists are getting quite large, and it may be necessary to
change the table representation.
This makes it possible to do so without changing all clients (again).
llvm-svn: 157854
The getPointerRegClass() hook can return register classes that depend on
the calling convention of the current function (ptr_rc_tailcall).
So far, we have been able to infer the calling convention from the
subtarget alone, but as we add support for multiple calling conventions
per target, that no longer works.
Patch by Yiannis Tsiouris!
llvm-svn: 156328
Affect on SD scheduling and postRA scheduling:
Printing the DAG will display the nodes in top-down topological order.
This matches the order within the MBB and makes my life much easier in general.
Affect on misched:
We don't need to track virtual register uses at all. This is awesome.
I also intend to rely on the SUnit ID as a topo-sort index. So if A < B then we cannot have an edge B -> A.
llvm-svn: 151135
opportunities that only present themselves after late optimizations
such as tail duplication .e.g.
## BB#1:
movl %eax, %ecx
movl %ecx, %eax
ret
The register allocator also leaves some of them around (due to false
dep between copies from phi-elimination, etc.)
This required some changes in codegen passes. Post-ra scheduler and the
pseudo-instruction expansion passes have been moved after branch folding
and tail merging. They were before branch folding before because it did
not always update block livein's. That's fixed now. The pass change makes
independently since we want to properly schedule instructions after
branch folding / tail duplication.
rdar://10428165
rdar://10640363
llvm-svn: 147716
generator to it. For non-bundle instructions, these behave exactly the same
as the MC layer API.
For properties like mayLoad / mayStore, look into the bundle and if any of the
bundled instructions has the property it would return true.
For properties like isPredicable, only return true if *all* of the bundled
instructions have the property.
For properties like canFoldAsLoad, isCompare, conservatively return false for
bundles.
llvm-svn: 146026
Avoid using the same register for two def operands or and earlyclobber
def and use operand. This fixes PR8986 and improves on the prior fix
for rdar://problem/8959122.
llvm-svn: 125089
<rdar://problem/8959122> illegal register operands for UMULL instruction in cfrac nightly test
I'm stil working on a unit test, but the case is:
rx = movcc rx, r3
r2 = ldr
r2, r3 = umull r2, r2
The anti-dep breaker should not convert this into an illegal instruction:
r2, r2 = umull
llvm-svn: 124932
scheduling change in svn 115121. The CriticalAntiDepBreaker had bad
liveness information. It was calculating the KillIndices for one scheduling
region in a basic block, rescheduling that region so the KillIndices were
no longer valid, and then using those wrong KillIndices to make decisions
for the next scheduling region. I've not been able to reduce a small
testcase for this. Radar 8502534.
llvm-svn: 115400
Craig Topper