on X86 Atom. Some of our tests failed because the tail merging part of
the BranchFolding pass was creating new basic blocks which did not
contain live-in information. When the anti-dependency code in the Post-RA
scheduler ran, it would sometimes rename the register containing
the function return value because the fact that the return value was
live-in to the subsequent block had been lost. To fix this, it is necessary
to run the RegisterScavenging code in the BranchFolding pass.
This patch makes sure that the register scavenging code is invoked
in the X86 subtarget only when post-RA scheduling is being done.
Post RA scheduling in the X86 subtarget is only done for Atom.
This patch adds a new function to the TargetRegisterClass to control
whether or not live-ins should be preserved during branch folding.
This is necessary in order for the anti-dependency optimizations done
during the PostRASchedulerList pass to work properly when doing
Post-RA scheduling for the X86 in general and for the Intel Atom in particular.
The patch adds and invokes the new function trackLivenessAfterRegAlloc()
instead of using the existing requiresRegisterScavenging().
It changes BranchFolding.cpp to call trackLivenessAfterRegAlloc() instead of
requiresRegisterScavenging(). It changes the all the targets that
implemented requiresRegisterScavenging() to also implement
trackLivenessAfterRegAlloc().
It adds an assertion in the Post RA scheduler to make sure that post RA
liveness information is available when it is needed.
It changes the X86 break-anti-dependencies test to use –mcpu=atom, in order
to avoid running into the added assertion.
Finally, this patch restores the use of anti-dependency checking
(which was turned off temporarily for the 3.1 release) for
Intel Atom in the Post RA scheduler.
Patch by Andy Zhang!
Thanks to Jakob and Anton for their reviews.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@155395 91177308-0d34-0410-b5e6-96231b3b80d8
ARMBaseRegisterInfo::canRealignStack was checking for variable-sized objects
but not for stack adjustments around calls. Use hasReservedCallFrame() to
check for both. The hasBasePointer function was already correctly checking
both conditions, so the effect of this was that a base pointer would be used
without checking whether the base pointer register could be reserved. I don't
have a small testcase for this.
<rdar://problem/11075906>
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@153110 91177308-0d34-0410-b5e6-96231b3b80d8
ARMFrameLowering::hasReservedCallFrame is already checking for variable
sized objects, so there's no point in checking it twice.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@153109 91177308-0d34-0410-b5e6-96231b3b80d8
The fpscr register contains both flags (set by FP operations/comparisons) and
control bits. The control bits (FPSCR) should be reserved, since they're always
available and needn't be defined before use. The flag bits (FPSCR_NZCV) should
like to be unreserved so they can be hoisted by MachineCSE. This fixes PR12165.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@152076 91177308-0d34-0410-b5e6-96231b3b80d8
When an outgoing call takes more than 2k of arguments on the stack, we
don't allocate that call frame in the prolog, but adjust the stack
pointer immediately before the call instead.
This causes problems with the emergency spill slot because PEI can't
track stack pointer adjustments on the second pass, and if the outgoing
arguments are too big, SP can't be used to reach the emergency spill
slot at all.
Work around these problems by ensuring there is a base or frame pointer
that can be used to access the emergency spill slot.
<rdar://problem/10917166>
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@151604 91177308-0d34-0410-b5e6-96231b3b80d8
Now that canRealignStack() understands frozen reserved registers, it is
safe to use it for aligned spill instructions.
It will only return true if the registers reserved at the beginning of
register allocation allow for dynamic stack realignment.
<rdar://problem/10625436>
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@147579 91177308-0d34-0410-b5e6-96231b3b80d8
Once register allocation has started the reserved registers are frozen.
Fix the ARM canRealignStack() hook to respect the frozen register state.
Now the hook returns false if register allocation was started with frame
pointer elimination enabled.
It also returns false if register allocation started without a reserved
base pointer, and stack realignment would require a base pointer. This
bug was breaking oggenc on armv6.
No test case, an upcoming patch will use this functionality to realign
the stack for spill slots when possible.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@147578 91177308-0d34-0410-b5e6-96231b3b80d8
This patch caused a miscompilation of oggenc because a frame pointer was
suddenly needed halfway through register allocation.
<rdar://problem/10625436>
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@147487 91177308-0d34-0410-b5e6-96231b3b80d8
Use the spill slot alignment as well as the local variable alignment to
determine when the stack needs to be realigned. This works now that the
ARM target can always realign the stack by using a base pointer.
Still respect the ARMBaseRegisterInfo::canRealignStack() function
vetoing a realigned stack. Don't use aligned spill code in that case.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@146997 91177308-0d34-0410-b5e6-96231b3b80d8
Use information computed while inferring new register classes to emit
accurate, table-driven implementations of getMatchingSuperRegClass().
Delete the old manual, error-prone implementations in the targets.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@146873 91177308-0d34-0410-b5e6-96231b3b80d8
change, now you need a TargetOptions object to create a TargetMachine. Clang
patch to follow.
One small functionality change in PTX. PTX had commented out the machine
verifier parts in their copy of printAndVerify. That now calls the version in
LLVMTargetMachine. Users of PTX who need verification disabled should rely on
not passing the command-line flag to enable it.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@145714 91177308-0d34-0410-b5e6-96231b3b80d8
ARMII::AddrModeT1_s, we need to take into account that if the frame register is
ARM::SP, then the number of bits is 8. If it's not ARM::SP, then the number of
bits is 5.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@141529 91177308-0d34-0410-b5e6-96231b3b80d8
useful if an optimization assumes the stack has been realigned. Credit to
Eli for his assistance.
rdar://10043857
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@140924 91177308-0d34-0410-b5e6-96231b3b80d8
This uses less memory and it reduces the complexity of sub-class
operations:
- hasSubClassEq() and friends become O(1) instead of O(N).
- getCommonSubClass() becomes O(N) instead of O(N^2).
In the future, TableGen will infer register classes. This makes it
cheap to add them.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@140898 91177308-0d34-0410-b5e6-96231b3b80d8
register dependency (rather than glue them together). This is general
goodness as it gives scheduler more freedom. However it is motivated by
a nasty bug in isel.
When a i64 sub is expanded to subc + sube.
libcall #1
\
\ subc
\ / \
\ / \
\ / libcall #2
sube
If the libcalls are not serialized (i.e. both have chains which are dag
entry), legalizer can serialize them in arbitrary orders. If it's
unlucky, it can force libcall #2 before libcall #1 in the above case.
subc
|
libcall #2
|
libcall #1
|
sube
However since subc and sube are "glued" together, this ends up being a
cycle when the scheduler combine subc and sube as a single scheduling
unit.
The right solution is to fix LegalizeType too chains the libcalls together.
However, LegalizeType is not processing nodes in order so that's harder than
it should be. For now, the move to physical register dependency will do.
rdar://10019576
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@138791 91177308-0d34-0410-b5e6-96231b3b80d8
Add the predicate operand to the instructions. Update the back end
accordingly where the instructions are used. Restrict the SP operands
to actually only be SP, as otherwise these break assembly parsing for the
normal instruction variants.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@138445 91177308-0d34-0410-b5e6-96231b3b80d8
to MCRegisterInfo. Also initialize the mapping at construction time.
This patch eliminate TargetRegisterInfo from TargetAsmInfo. It's another step
towards fixing the layering violation.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@135424 91177308-0d34-0410-b5e6-96231b3b80d8
Unlike Thumb1, Thumb2 does not have dedicated encodings for adjusting the
stack pointer. It can just use the normal add-register-immediate encoding
since it can use all registers as a source, not just R0-R7. The extra
instruction definitions are just duplicates of the normal instructions with
the (not well enforced) constraint that the source register was SP.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@134114 91177308-0d34-0410-b5e6-96231b3b80d8
sink them into MC layer.
- Added MCInstrInfo, which captures the tablegen generated static data. Chang
TargetInstrInfo so it's based off MCInstrInfo.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@134021 91177308-0d34-0410-b5e6-96231b3b80d8
target machine from those that are only needed by codegen. The goal is to
sink the essential target description into MC layer so we can start building
MC based tools without needing to link in the entire codegen.
First step is to refactor TargetRegisterInfo. This patch added a base class
MCRegisterInfo which TargetRegisterInfo is derived from. Changed TableGen to
separate register description from the rest of the stuff.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@133782 91177308-0d34-0410-b5e6-96231b3b80d8
