llvm-6502/lib/Target/Sparc
Dan Gohman e8be6c6391 Add a new function, ReplaceAllUsesOfValuesWith, which handles bulk
replacement of multiple values. This is slightly more efficient
than doing multiple ReplaceAllUsesOfValueWith calls, and theoretically
could be optimized even further. However, an important property of this
new function is that it handles the case where the source value set and
destination value set overlap. This makes it feasible for isel to use
SelectNodeTo in many very common cases, which is advantageous because
SelectNodeTo avoids a temporary node and it doesn't require CSEMap
updates for users of values that don't change position.

Revamp MorphNodeTo, which is what does all the work of SelectNodeTo, to
handle operand lists more efficiently, and to correctly handle a number
of corner cases to which its new wider use exposes it.

This commit also includes a change to the encoding of post-isel opcodes
in SDNodes; now instead of being sandwiched between the target-independent
pre-isel opcodes and the target-dependent pre-isel opcodes, post-isel
opcodes are now represented as negative values. This makes it possible
to test if an opcode is pre-isel or post-isel without having to know
the size of the current target's post-isel instruction set.

These changes speed up llc overall by 3% and reduce memory usage by 10%
on the InstructionCombining.cpp testcase with -fast and -regalloc=local.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@53728 91177308-0d34-0410-b5e6-96231b3b80d8
2008-07-17 19:10:17 +00:00
..
DelaySlotFiller.cpp rename TargetInstrDescriptor -> TargetInstrDesc. 2008-01-07 07:27:27 +00:00
FPMover.cpp rename MachineInstr::setInstrDescriptor -> setDesc 2008-01-11 18:10:50 +00:00
Makefile Start moving sparc to use SparcCallingConv.td, switching over 2008-03-17 05:41:48 +00:00
README.txt fix CodeGen/Generic/2008-01-25-dag-combine-mul.ll on sparc, PR2105 2008-02-28 05:44:20 +00:00
Sparc.h Remove attribution from file headers, per discussion on llvmdev. 2007-12-29 20:36:04 +00:00
Sparc.td Start moving sparc to use SparcCallingConv.td, switching over 2008-03-17 05:41:48 +00:00
SparcAsmPrinter.cpp Fix the build by adding a #include. 2008-07-10 01:44:27 +00:00
SparcCallingConv.td Check in some #ifdef'd out code switching call argument 2008-03-17 06:58:37 +00:00
SparcInstrFormats.td Remove attribution from file headers, per discussion on llvmdev. 2007-12-29 20:36:04 +00:00
SparcInstrInfo.cpp Pool-allocation for MachineInstrs, MachineBasicBlocks, and 2008-07-07 23:14:23 +00:00
SparcInstrInfo.h Change target-specific classes to use more precise static types. 2008-05-14 01:58:56 +00:00
SparcInstrInfo.td Replace all target specific implicit def instructions with a target independent one: TargetInstrInfo::IMPLICIT_DEF. 2008-03-15 00:03:38 +00:00
SparcISelDAGToDAG.cpp Add a new function, ReplaceAllUsesOfValuesWith, which handles bulk 2008-07-17 19:10:17 +00:00
SparcISelLowering.cpp Pool-allocation for MachineInstrs, MachineBasicBlocks, and 2008-07-07 23:14:23 +00:00
SparcISelLowering.h Replace some std::vectors that showed up in heap profiling with 2008-06-30 20:31:15 +00:00
SparcRegisterInfo.cpp Move reMaterialize() from TargetRegisterInfo to TargetInstrInfo. 2008-03-31 20:40:39 +00:00
SparcRegisterInfo.h Move reMaterialize() from TargetRegisterInfo to TargetInstrInfo. 2008-03-31 20:40:39 +00:00
SparcRegisterInfo.td Remove attribution from file headers, per discussion on llvmdev. 2007-12-29 20:36:04 +00:00
SparcSubtarget.cpp Remove attribution from file headers, per discussion on llvmdev. 2007-12-29 20:36:04 +00:00
SparcSubtarget.h Remove attribution from file headers, per discussion on llvmdev. 2007-12-29 20:36:04 +00:00
SparcTargetAsmInfo.cpp Remove attribution from file headers, per discussion on llvmdev. 2007-12-29 20:36:04 +00:00
SparcTargetAsmInfo.h Remove attribution from file headers, per discussion on llvmdev. 2007-12-29 20:36:04 +00:00
SparcTargetMachine.cpp Clean up the use of static and anonymous namespaces. This turned up 2008-05-13 00:00:25 +00:00
SparcTargetMachine.h Change target-specific classes to use more precise static types. 2008-05-14 01:58:56 +00:00

To-do
-----

* Keep the address of the constant pool in a register instead of forming its
  address all of the time.
* We can fold small constant offsets into the %hi/%lo references to constant
  pool addresses as well.
* When in V9 mode, register allocate %icc[0-3].
* Add support for isel'ing UMUL_LOHI instead of marking it as Expand.
* Emit the 'Branch on Integer Register with Prediction' instructions.  It's
  not clear how to write a pattern for this though:

float %t1(int %a, int* %p) {
        %C = seteq int %a, 0
        br bool %C, label %T, label %F
T:
        store int 123, int* %p
        br label %F
F:
        ret float undef
}

codegens to this:

t1:
        save -96, %o6, %o6
1)      subcc %i0, 0, %l0
1)      bne .LBBt1_2    ! F
        nop
.LBBt1_1:       ! T
        or %g0, 123, %l0
        st %l0, [%i1]
.LBBt1_2:       ! F
        restore %g0, %g0, %g0
        retl
        nop

1) should be replaced with a brz in V9 mode.

* Same as above, but emit conditional move on register zero (p192) in V9 
  mode.  Testcase:

int %t1(int %a, int %b) {
        %C = seteq int %a, 0
        %D = select bool %C, int %a, int %b
        ret int %D
}

* Emit MULX/[SU]DIVX instructions in V9 mode instead of fiddling 
  with the Y register, if they are faster.

* Codegen bswap(load)/store(bswap) -> load/store ASI

* Implement frame pointer elimination, e.g. eliminate save/restore for 
  leaf fns.
* Fill delay slots