Add EXTRA_OPTIONS on the llvmgxx command line.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@50217 91177308-0d34-0410-b5e6-96231b3b80d8

Add EXTRA_OPTIONS on the llvmgcc command line.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@50216 91177308-0d34-0410-b5e6-96231b3b80d8

overlook Output directory

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@50212 91177308-0d34-0410-b5e6-96231b3b80d8

- Check if a register is livein before removing it. It may have already been removed.
- Do not iterate over SmallPtrSet, the order of iteration is not deterministic.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@50209 91177308-0d34-0410-b5e6-96231b3b80d8

% -> @

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@50206 91177308-0d34-0410-b5e6-96231b3b80d8

Doc updates/edits, contributed by Terence Parr!

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@50205 91177308-0d34-0410-b5e6-96231b3b80d8

code restructuring, not functionality change.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@50203 91177308-0d34-0410-b5e6-96231b3b80d8

Don't replace multiple result of calls with undef,
sccp tracks getresult values, not call values in this
case.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@50202 91177308-0d34-0410-b5e6-96231b3b80d8

code cleanup, no functionality change.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@50201 91177308-0d34-0410-b5e6-96231b3b80d8

Split some code out of the main SimplifyCFG loop into its own function.
Fix said code to handle merging return instructions together correctly
when handling multiple return values.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@50199 91177308-0d34-0410-b5e6-96231b3b80d8

Make these variables static.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@50196 91177308-0d34-0410-b5e6-96231b3b80d8

Disable building of llvm2cpp. The directory will be removed before 2.3 release.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@50193 91177308-0d34-0410-b5e6-96231b3b80d8

Drop dead includes

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@50192 91177308-0d34-0410-b5e6-96231b3b80d8

Fix tests due to llvm2cpp move to llc target

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@50191 91177308-0d34-0410-b5e6-96231b3b80d8

Adjust option names for C++ backend

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@50190 91177308-0d34-0410-b5e6-96231b3b80d8

First step of implementing PR1538: move llvm2cpp logic to new 'target'

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@50189 91177308-0d34-0410-b5e6-96231b3b80d8

Initial CBE support for multiple return values.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@50187 91177308-0d34-0410-b5e6-96231b3b80d8

tighten up verifier checks which missed cases where
return instrs operands didn't match up with function results.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@50182 91177308-0d34-0410-b5e6-96231b3b80d8

Use isa instead of dyn_cast.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@50181 91177308-0d34-0410-b5e6-96231b3b80d8

Add support to codegen for getresult instructions with undef operands.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@50180 91177308-0d34-0410-b5e6-96231b3b80d8

Check type instead of no. of operands.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@50179 91177308-0d34-0410-b5e6-96231b3b80d8

Allow llvm-as to parse a getresult with an undef operand.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@50175 91177308-0d34-0410-b5e6-96231b3b80d8

Rewrite previous patch to suit Chris's preference.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@50174 91177308-0d34-0410-b5e6-96231b3b80d8

Unbreak JIT

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@50173 91177308-0d34-0410-b5e6-96231b3b80d8

Disable stack realignment for these tests

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@50172 91177308-0d34-0410-b5e6-96231b3b80d8

Fix test becase ABI stack alignment dropped to 'normal' value

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@50171 91177308-0d34-0410-b5e6-96231b3b80d8

Fix test, instruction count is valid only if stack is not realigned

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@50170 91177308-0d34-0410-b5e6-96231b3b80d8

Fix typo

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@50169 91177308-0d34-0410-b5e6-96231b3b80d8

Only allow increase of max alignment value

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@50168 91177308-0d34-0410-b5e6-96231b3b80d8

Be over-conservative: scan for all used virtual registers and calculate maximal stack alignment in assumption, that there will be spill of vector register.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@50167 91177308-0d34-0410-b5e6-96231b3b80d8

Add X86 Maximal Stack Alignment Calculator Pass before RA

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@50166 91177308-0d34-0410-b5e6-96231b3b80d8

Add facility for pre-RA passes

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@50165 91177308-0d34-0410-b5e6-96231b3b80d8

Use precomputed value, if any

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@50164 91177308-0d34-0410-b5e6-96231b3b80d8

Do proper book-keeping of offsets and prologue/epilogue code for stack realignment

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@50163 91177308-0d34-0410-b5e6-96231b3b80d8

If stack realignment is used - incoming args will use EBP as base register and locals - ESP

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@50162 91177308-0d34-0410-b5e6-96231b3b80d8

Eastimate required stack alignment early, so we can decide, whether we will need frame pointer or not

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@50161 91177308-0d34-0410-b5e6-96231b3b80d8

Cleanup

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@50160 91177308-0d34-0410-b5e6-96231b3b80d8

Cleanup

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@50159 91177308-0d34-0410-b5e6-96231b3b80d8

Simplify

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@50158 91177308-0d34-0410-b5e6-96231b3b80d8

Make stack alignment options global for all targets

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@50157 91177308-0d34-0410-b5e6-96231b3b80d8

Provide option for enabling-disabling stack realignment

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@50156 91177308-0d34-0410-b5e6-96231b3b80d8

Disable stack realignment for functions with dynamic-sized alloca's

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@50155 91177308-0d34-0410-b5e6-96231b3b80d8

Provide ABI-correct stack alignment

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@50154 91177308-0d34-0410-b5e6-96231b3b80d8

Provide convenient helpers for some operations

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@50153 91177308-0d34-0410-b5e6-96231b3b80d8

Whitespace cleanup

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@50152 91177308-0d34-0410-b5e6-96231b3b80d8

Fix some whitespace.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@50151 91177308-0d34-0410-b5e6-96231b3b80d8

Use the Create static method for some of these objects. They no longer
have public constructors. This should fix PR2246.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@50145 91177308-0d34-0410-b5e6-96231b3b80d8

simplify code for propagation of constant arguments into
callees.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@50142 91177308-0d34-0410-b5e6-96231b3b80d8

Fix a number of bugs in ipconstantprop, simplify the code, fit in 80 cols,
fix read after free bug (PR2238).

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@50141 91177308-0d34-0410-b5e6-96231b3b80d8

Rewrite multiple return value handling in SCCP.  Before, the -sccp pass
would turn every getresult instruction into undef.  This helps with
rdar://5778210

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@50140 91177308-0d34-0410-b5e6-96231b3b80d8

regenerate

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@50139 91177308-0d34-0410-b5e6-96231b3b80d8

Validate that the result of a function type is valid using shared
logic with vmcore.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@50138 91177308-0d34-0410-b5e6-96231b3b80d8

Enforce that multiple return values have to have at least one result.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@50137 91177308-0d34-0410-b5e6-96231b3b80d8

remove this testcase.  It isn't testing loop rotate, it is testing all
of -std-compile-opts and is now failing because other passes are generating
IR that looks different to input of loop rotate.  Devang, please
introduce a testcase that only runs loop rotate.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@50136 91177308-0d34-0410-b5e6-96231b3b80d8

returning an empty multiple return list is not valid.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@50135 91177308-0d34-0410-b5e6-96231b3b80d8

fix description of 'ret' to be more correct with multiple return
values.  Clarify that it is impossible to 'multiply return' a
struct with zero elements.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@50131 91177308-0d34-0410-b5e6-96231b3b80d8

Allow undef as an operand to getresult.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@50130 91177308-0d34-0410-b5e6-96231b3b80d8

Verify that the operand of a getresult instruction is a
call/invoke or undef.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@50129 91177308-0d34-0410-b5e6-96231b3b80d8

make this test more interesting.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@50128 91177308-0d34-0410-b5e6-96231b3b80d8

distill down the essense of this test.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@50125 91177308-0d34-0410-b5e6-96231b3b80d8

new test

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@50123 91177308-0d34-0410-b5e6-96231b3b80d8

Do not change the type of a ByVal argument to a
type of a different size.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@50121 91177308-0d34-0410-b5e6-96231b3b80d8

Don't do: "(X & 4) >> 1 == 2  --> (X & 4) == 4" if there are more than one uses of the shift result.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@50118 91177308-0d34-0410-b5e6-96231b3b80d8

Start doing the significantly useful part of jump threading: handle cases
where a comparison has a phi input and that phi is a constant.  For example,
stuff like:

  Threading edge through bool from 'bb2149' to 'bb2231' with cost: 1, across block:
bb2237: ; preds = %bb2231, %bb2149
%tmp2328.rle = phi i32 [ %tmp2232, %bb2231 ], [ %tmp2232439, %bb2149 ] ; <i32> [#uses=2]
%done.0 = phi i32 [ %done.2, %bb2231 ], [ 0, %bb2149 ] ; <i32> [#uses=1]
%tmp2239 = icmp eq i32 %done.0, 0 ; <i1> [#uses=1]
br i1 %tmp2239, label %bb2231, label %bb2327

or

bb38.i298: ; preds = %bb33.i295, %bb1693
%tmp39.i296.rle = phi %struct.ibox* [ null, %bb1693 ], [ %tmp39.i296.rle1109, %bb33.i295 ] ; <%struct.ibox*> [#uses=2]
%minspan.1.i291.reg2mem.1 = phi i32 [ 32000, %bb1693 ], [ %minspan.0.i288, %bb33.i295 ] ; <i32> [#uses=1]
%tmp40.i297 = icmp eq %struct.ibox* %tmp39.i296.rle, null ; <i1> [#uses=1]
br i1 %tmp40.i297, label %implfeeds.exit311, label %bb43.i301

This triggers thousands of times in spec.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@50110 91177308-0d34-0410-b5e6-96231b3b80d8

Dig through multiple levels of AND to thread jumps if needed.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@50106 91177308-0d34-0410-b5e6-96231b3b80d8

Move MemCpyOpt after GVN.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@50097 91177308-0d34-0410-b5e6-96231b3b80d8

Teach jump threading to thread through blocks like:

  br (and X, phi(Y, Z, false)), label L1, label L2

This triggers once on 252.eon and 6 times on 176.gcc.  Blocks
in question often look like this:

bb262: ; preds = %bb261, %bb248
%iftmp.251.0 = phi i1 [ true, %bb261 ], [ false, %bb248 ] ; <i1> [#uses=4]
%tmp270 = icmp eq %struct.rtx_def* %tmp.0.i, null ; <i1> [#uses=1]
%bothcond = or i1 %iftmp.251.0, %tmp270 ; <i1> [#uses=1]
br i1 %bothcond, label %bb288, label %bb273

In this case, it is clear that it doesn't matter if tmp.0.i is null when coming from bb261.  When coming from bb248, it is all that matters.

Another random example:

check_asm_operands.exit: ; preds = %check_asm_operands.exit.thr_comm, %bb30.i, %bb12.i, %bb6.i413
%tmp.0.i420 = phi i1 [ true, %bb6.i413 ], [ true, %bb12.i ], [ true, %bb30.i ], [ false, %check_asm_operands.exit.thr_comm ; <i1> [#uses=1]
call void @llvm.stackrestore( i8* %savedstack ) nounwind
%tmp4389 = icmp eq i32 %added_sets_1.0, 0 ; <i1> [#uses=1]
%tmp4394 = icmp eq i32 %added_sets_2.0, 0 ; <i1> [#uses=1]
%bothcond80 = and i1 %tmp4389, %tmp4394 ; <i1> [#uses=1]
%bothcond81 = and i1 %bothcond80, %tmp.0.i420 ; <i1> [#uses=1]
br i1 %bothcond81, label %bb4398, label %bb4397

Here is the case from 252.eon:

bb290.i.i: ; preds = %bb23.i57.i.i, %bb8.i39.i.i, %bb100.i.i, %bb100.i.i, %bb85.i.i110
%myEOF.1.i.i = phi i1 [ true, %bb100.i.i ], [ true, %bb100.i.i ], [ true, %bb85.i.i110 ], [ true, %bb8.i39.i.i ], [ false, %bb23.i57.i.i ] ; <i1> [#uses=2]
%i.4.i.i = phi i32 [ %i.1.i.i, %bb85.i.i110 ], [ %i.0.i.i, %bb100.i.i ], [ %i.0.i.i, %bb100.i.i ], [ %i.3.i.i, %bb8.i39.i.i ], [ %i.3.i.i, %bb23.i57.i.i ] ; <i32> [#uses=3]
%tmp292.i.i = load i8* %tmp16.i.i100, align 1 ; <i8> [#uses=1]
%tmp293.not.i.i = icmp ne i8 %tmp292.i.i, 0 ; <i1> [#uses=1]
%bothcond.i.i = and i1 %tmp293.not.i.i, %myEOF.1.i.i ; <i1> [#uses=1]
br i1 %bothcond.i.i, label %bb202.i.i, label %bb301.i.i
  Factoring out 3 common predecessors.

On the path from any blocks other than bb23.i57.i.i, the load and compare
are dead.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@50096 91177308-0d34-0410-b5e6-96231b3b80d8

Added command line option -no-lazy to disable JIT lazy compilation.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@50095 91177308-0d34-0410-b5e6-96231b3b80d8

refactor some code, no functionality change.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@50094 91177308-0d34-0410-b5e6-96231b3b80d8

add a basic testcase.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@50093 91177308-0d34-0410-b5e6-96231b3b80d8

Whoops! Undo r50087, unbreak the build.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@50088 91177308-0d34-0410-b5e6-96231b3b80d8

Reverse r47989. Part of removing 'unwinds to' support.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@50087 91177308-0d34-0410-b5e6-96231b3b80d8

Start removing 'unwinds to' support from mainline in preparation for 2.3.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@50086 91177308-0d34-0410-b5e6-96231b3b80d8

Add MemCpyOpt to LTO.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@50081 91177308-0d34-0410-b5e6-96231b3b80d8

remove dead code.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@50080 91177308-0d34-0410-b5e6-96231b3b80d8

optimize "p != gep p, ..." better.  This allows us to compile
getelementptr-seteq.ll into:

define i1 @test(i64 %X, %S* %P) {
%C = icmp eq i64 %X, -1 ; <i1> [#uses=1]
ret i1 %C
}

instead of:

define i1 @test(i64 %X, %S* %P) {
%A.idx.mask = and i64 %X, 4611686018427387903 ; <i64> [#uses=1]
%C = icmp eq i64 %A.idx.mask, 4611686018427387903 ; <i1> [#uses=1]
ret i1 %C
}

And fixes the second half of PR2235.  This speeds up the insertion sort
case by 45%, from 1.12s to 0.77s.  In practice, this will significantly
speed up for loops structured like:

for (double *P = Base + N; P != Base; --P)
  ...

Which happens frequently for C++ iterators.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@50079 91177308-0d34-0410-b5e6-96231b3b80d8

more fallout from Nicholas' asmprinter patch.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@50078 91177308-0d34-0410-b5e6-96231b3b80d8

Implement an x86-64 ABI detail of passing structs by hidden first
argument. The x86-64 ABI requires the incoming value of %rdi to
be copied to %rax on exit from a function that is returning a
large C struct.

Also, add a README-X86-64 entry detailing the missed optimization
opportunity and proposing an alternative approach.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@50075 91177308-0d34-0410-b5e6-96231b3b80d8

fix some residual old API that fell thru the cracks of the conversion script, closes llvm.org/bugs/show_bug.cgi?id=2246

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@50062 91177308-0d34-0410-b5e6-96231b3b80d8

Fix an out-of-bounds access in -view-sunit-dags in the case of an
empty ScheduleDAG.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@50054 91177308-0d34-0410-b5e6-96231b3b80d8

Fix the encoding of the MMX movd that moves from MMX to 64-bit GPR.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@50053 91177308-0d34-0410-b5e6-96231b3b80d8

Fix the way AliasSet::print prints "may alias".

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@50051 91177308-0d34-0410-b5e6-96231b3b80d8

fix grammar-o, thanks to Duncan for noticing.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@50047 91177308-0d34-0410-b5e6-96231b3b80d8

Make these structs larger to ensure that they
are returned by struct return.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@50038 91177308-0d34-0410-b5e6-96231b3b80d8

Make the struct bigger, to ensure it is returned
by struct return.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@50037 91177308-0d34-0410-b5e6-96231b3b80d8

Use GVN in LTO instead of GCSE+LoadVN.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@50036 91177308-0d34-0410-b5e6-96231b3b80d8

Remove unneeded #include's.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@50035 91177308-0d34-0410-b5e6-96231b3b80d8

Refactor memcpyopt based on Chris' suggestions.  Consolidate several functions
and simplify code that was fallout from the separation of memcpyopt and gvn.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@50034 91177308-0d34-0410-b5e6-96231b3b80d8

Fix a "large integer implicitly truncated to unsigned type"
warning.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@50033 91177308-0d34-0410-b5e6-96231b3b80d8

don't print dominators every time it is computed with -debug.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@50032 91177308-0d34-0410-b5e6-96231b3b80d8

another bug introduced in r47802 by nicholas, for no apparent reason.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@50031 91177308-0d34-0410-b5e6-96231b3b80d8

Add an ugly note.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@50029 91177308-0d34-0410-b5e6-96231b3b80d8

Add jump threading to liblto.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@50028 91177308-0d34-0410-b5e6-96231b3b80d8

run the jump threading pass in llvm-ld also

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@50027 91177308-0d34-0410-b5e6-96231b3b80d8

enable jump threading pass by default.  This causes no miscompilations
and can significantly shrinkify some code, particularly from C++ land.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@50025 91177308-0d34-0410-b5e6-96231b3b80d8

fix a bug introduced by Nicholas' "unwinds to" stuff: we
lost newlines between blocks.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@50024 91177308-0d34-0410-b5e6-96231b3b80d8

don't assume that the argument passed to fprintf("%s"  is a string.  This
fixes a crash in opt on 433.milc.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@50023 91177308-0d34-0410-b5e6-96231b3b80d8

Use the new SplitBlockPredecessors to implement a todo.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@50022 91177308-0d34-0410-b5e6-96231b3b80d8

Move SplitBlockPredecessors out of loopsimplify into BasicBlockUtils.h
as a global helper function.  At the same type, switch it from taking
a vector of predecessors to an arbitrary sequential input.  This allows
us to switch LoopSimplify to use a SmallVector for various temporary
vectors that it passed into SplitBlockPredecessors.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@50020 91177308-0d34-0410-b5e6-96231b3b80d8

Move domtree/frontier updating earlier, allowing us to use it to update phi
nodes, removing a hack.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@50019 91177308-0d34-0410-b5e6-96231b3b80d8