llvm-6502/lib/Target/CellSPU
Preston Gurd 6a8c7bf8e7 This patch fixes a problem which arose when using the Post-RA scheduler
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
2012-04-23 21:39:35 +00:00
..
MCTargetDesc Remove some unnecessary forward declarations. 2012-03-22 06:52:14 +00:00
TargetInfo LLVMBuild: Remove trailing newline, which irked me. 2011-12-12 19:48:00 +00:00
CellSDKIntrinsics.td Emacs-tag and some comment fix for all ARM, CellSPU, Hexagon, MBlaze, MSP430, PPC, PTX, Sparc, X86, XCore. 2012-02-18 12:03:15 +00:00
CMakeLists.txt Fix up the CMake build for the new files added in r146960, they're 2011-12-20 08:42:11 +00:00
LLVMBuild.txt LLVMBuild: Introduce a common section which currently has a list of the 2011-12-12 22:45:54 +00:00
Makefile Next round of MC refactoring. This patch factor MC table instantiations, MC 2011-07-14 20:59:42 +00:00
README.txt
SPU64InstrInfo.td Emacs-tag and some comment fix for all ARM, CellSPU, Hexagon, MBlaze, MSP430, PPC, PTX, Sparc, X86, XCore. 2012-02-18 12:03:15 +00:00
SPU128InstrInfo.td Emacs-tag and some comment fix for all ARM, CellSPU, Hexagon, MBlaze, MSP430, PPC, PTX, Sparc, X86, XCore. 2012-02-18 12:03:15 +00:00
SPU.h Emacs-tag and some comment fix for all ARM, CellSPU, Hexagon, MBlaze, MSP430, PPC, PTX, Sparc, X86, XCore. 2012-02-18 12:03:15 +00:00
SPU.td Emacs-tag and some comment fix for all ARM, CellSPU, Hexagon, MBlaze, MSP430, PPC, PTX, Sparc, X86, XCore. 2012-02-18 12:03:15 +00:00
SPUAsmPrinter.cpp Emacs-tag and some comment fix for all ARM, CellSPU, Hexagon, MBlaze, MSP430, PPC, PTX, Sparc, X86, XCore. 2012-02-18 12:03:15 +00:00
SPUCallingConv.td Remove unused CCIfSubtarget. 2012-04-17 11:29:05 +00:00
SPUFrameLowering.cpp Reorder includes in Target backends to following coding standards. Remove some superfluous forward declarations. 2012-03-17 18:46:09 +00:00
SPUFrameLowering.h Emacs-tag and some comment fix for all ARM, CellSPU, Hexagon, MBlaze, MSP430, PPC, PTX, Sparc, X86, XCore. 2012-02-18 12:03:15 +00:00
SPUHazardRecognizers.cpp
SPUHazardRecognizers.h
SPUInstrBuilder.h Emacs-tag and some comment fix for all ARM, CellSPU, Hexagon, MBlaze, MSP430, PPC, PTX, Sparc, X86, XCore. 2012-02-18 12:03:15 +00:00
SPUInstrFormats.td Emacs-tag and some comment fix for all ARM, CellSPU, Hexagon, MBlaze, MSP430, PPC, PTX, Sparc, X86, XCore. 2012-02-18 12:03:15 +00:00
SPUInstrInfo.cpp Convert more uses of XXXRegisterClass to &XXXRegClass. No functional change since they are equivalent. 2012-04-20 07:30:17 +00:00
SPUInstrInfo.h Reorder includes in Target backends to following coding standards. Remove some superfluous forward declarations. 2012-03-17 18:46:09 +00:00
SPUInstrInfo.td Mark 'branch indirect' instruction as an indirect branch. 2011-10-13 11:40:03 +00:00
SPUISelDAGToDAG.cpp More dead code removal (using -Wunreachable-code) 2012-01-20 21:51:11 +00:00
SPUISelLowering.cpp Convert more uses of XXXRegisterClass to &XXXRegClass. No functional change since they are equivalent. 2012-04-20 07:30:17 +00:00
SPUISelLowering.h Always compute all the bits in ComputeMaskedBits. 2012-04-04 12:51:34 +00:00
SPUMachineFunction.cpp Emacs-tag and some comment fix for all ARM, CellSPU, Hexagon, MBlaze, MSP430, PPC, PTX, Sparc, X86, XCore. 2012-02-18 12:03:15 +00:00
SPUMachineFunction.h Unweaken vtables as per http://llvm.org/docs/CodingStandards.html#ll_virtual_anch 2011-12-20 02:50:00 +00:00
SPUMathInstr.td Emacs-tag and some comment fix for all ARM, CellSPU, Hexagon, MBlaze, MSP430, PPC, PTX, Sparc, X86, XCore. 2012-02-18 12:03:15 +00:00
SPUNodes.td Emacs-tag and some comment fix for all ARM, CellSPU, Hexagon, MBlaze, MSP430, PPC, PTX, Sparc, X86, XCore. 2012-02-18 12:03:15 +00:00
SPUNopFiller.cpp Emacs-tag and some comment fix for all ARM, CellSPU, Hexagon, MBlaze, MSP430, PPC, PTX, Sparc, X86, XCore. 2012-02-18 12:03:15 +00:00
SPUOperands.td Emacs-tag and some comment fix for all ARM, CellSPU, Hexagon, MBlaze, MSP430, PPC, PTX, Sparc, X86, XCore. 2012-02-18 12:03:15 +00:00
SPURegisterInfo.cpp Reorder includes in Target backends to following coding standards. Remove some superfluous forward declarations. 2012-03-17 18:46:09 +00:00
SPURegisterInfo.h This patch fixes a problem which arose when using the Post-RA scheduler 2012-04-23 21:39:35 +00:00
SPURegisterInfo.td Emacs-tag and some comment fix for all ARM, CellSPU, Hexagon, MBlaze, MSP430, PPC, PTX, Sparc, X86, XCore. 2012-02-18 12:03:15 +00:00
SPURegisterNames.h
SPUSchedule.td Emacs-tag and some comment fix for all ARM, CellSPU, Hexagon, MBlaze, MSP430, PPC, PTX, Sparc, X86, XCore. 2012-02-18 12:03:15 +00:00
SPUSelectionDAGInfo.cpp
SPUSelectionDAGInfo.h
SPUSubtarget.cpp Prune some includes 2012-03-27 07:54:11 +00:00
SPUSubtarget.h
SPUTargetMachine.cpp Reorder includes in Target backends to following coding standards. Remove some superfluous forward declarations. 2012-03-17 18:46:09 +00:00
SPUTargetMachine.h Reorder includes in Target backends to following coding standards. Remove some superfluous forward declarations. 2012-03-17 18:46:09 +00:00

//===- README.txt - Notes for improving CellSPU-specific code gen ---------===//

This code was contributed by a team from the Computer Systems Research
Department in The Aerospace Corporation:

- Scott Michel (head bottle washer and much of the non-floating point
  instructions)
- Mark Thomas (floating point instructions)
- Michael AuYeung (intrinsics)
- Chandler Carruth (LLVM expertise)
- Nehal Desai (debugging, i32 operations, RoadRunner SPU expertise)

Some minor fixes added by Kalle Raiskila.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, NONINFRINGEMENT, OR
OTHERWISE.  IN NO EVENT SHALL THE AEROSPACE CORPORATION BE LIABLE FOR DAMAGES
OF ANY KIND OR NATURE WHETHER BASED IN CONTRACT, TORT, OR OTHERWISE ARISING
OUT OF OR IN CONNECTION WITH THE USE OF THE SOFTWARE INCLUDING, WITHOUT
LIMITATION, DAMAGES RESULTING FROM LOST OR CONTAMINATED DATA, LOST PROFITS OR
REVENUE, COMPUTER MALFUNCTION, OR FOR ANY SPECIAL, INCIDENTAL, CONSEQUENTIAL,
OR PUNITIVE  DAMAGES, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGES OR
SUCH DAMAGES ARE FORESEEABLE.

---------------------------------------------------------------------------
--WARNING--:
--WARNING--: The CellSPU work is work-in-progress and "alpha" quality code.
--WARNING--:

If you are brave enough to try this code or help to hack on it, be sure
to add 'spu' to configure's --enable-targets option, e.g.:

        ./configure <your_configure_flags_here> \
           --enable-targets=x86,x86_64,powerpc,spu

---------------------------------------------------------------------------

TODO:
* Create a machine pass for performing dual-pipeline scheduling specifically
  for CellSPU, and insert branch prediction instructions as needed.

* i32 instructions:

  * i32 division (work-in-progress)

* i64 support (see i64operations.c test harness):

  * shifts and comparison operators: done
  * sign and zero extension: done
  * addition: done
  * subtraction: needed
  * multiplication: done

* i128 support:

  * zero extension, any extension: done
  * sign extension: done
  * arithmetic operators (add, sub, mul, div): needed
  * logical operations (and, or, shl, srl, sra, xor, nor, nand): needed

    * or: done

* f64 support

  * Comparison operators:
    SETOEQ              unimplemented
    SETOGT              unimplemented
    SETOGE              unimplemented
    SETOLT              unimplemented
    SETOLE              unimplemented
    SETONE              unimplemented
    SETO                done (lowered)
    SETUO               done (lowered)
    SETUEQ              unimplemented
    SETUGT              unimplemented
    SETUGE              unimplemented
    SETULT              unimplemented
    SETULE              unimplemented
    SETUNE              unimplemented

* LLVM vector suport

  * VSETCC needs to be implemented. It's pretty straightforward to code, but
    needs implementation.

* Intrinsics

  * spu.h instrinsics added but not tested. Need to have an operational
    llvm-spu-gcc in order to write a unit test harness.

===-------------------------------------------------------------------------===