Chris Dewhurst 3202f065b8 [Sparc] Leon errata fix passes.
Errata fixes for various errata in different versions of the Leon variants of the Sparc 32 bit processor.

The nature of the errata are listed in the comments preceding the errata fix passes. Relevant unit tests are implemented for each of these.

Note: Running clang-format has changed a few other lines too, unrelated to the implemented errata fixes. These have been left in as this keeps the code formatting consistent.

Differential Revision: http://reviews.llvm.org/D21960

llvm-svn: 274856
2016-07-08 15:33:56 +00:00
..
2016-06-30 18:25:11 +00:00
2016-01-26 21:29:08 +00:00
2016-07-08 15:33:56 +00:00
2016-07-08 15:33:56 +00:00
2016-02-26 11:38:24 +00:00
2016-07-08 15:33:56 +00:00
2016-04-18 09:17:29 +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

* Use %g0 directly to materialize 0. No instruction is required.