Chris used to use '...' instead of proper grammar.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@85775 91177308-0d34-0410-b5e6-96231b3b80d8

remove some extraneous llvmcontext stuff.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@85774 91177308-0d34-0410-b5e6-96231b3b80d8

change LatticeVal to use PointerIntPair to save some space.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@85773 91177308-0d34-0410-b5e6-96231b3b80d8

fix instcombine to only do store sinking when the alignments
of the two loads agree.  Propagate that onto the new store.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@85772 91177308-0d34-0410-b5e6-96231b3b80d8

merge a test into store.ll

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@85771 91177308-0d34-0410-b5e6-96231b3b80d8

convert to filecheck

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@85770 91177308-0d34-0410-b5e6-96231b3b80d8

Add missing end-tag.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@85769 91177308-0d34-0410-b5e6-96231b3b80d8

Some formatting changes.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@85768 91177308-0d34-0410-b5e6-96231b3b80d8

Handle splats of undefs properly. This includes the testcase for PR5364 as well.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@85767 91177308-0d34-0410-b5e6-96231b3b80d8

Do not infer the target type for COPY_TO_REGCLASS from dest regclass, this won't work if it can contain several types. Require explicit result type for the node for now. This fixes PR5364.

PS: It seems that blackfin usage of copy_to_regclass is completely bogus!

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@85766 91177308-0d34-0410-b5e6-96231b3b80d8

64-bit FP loads & stores operate on both NEON and VFP pipelines.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@85765 91177308-0d34-0410-b5e6-96231b3b80d8

Use NEON reg-reg moves, where profitable. This reduces "domain-cross" stalls, when we used to mix vfp and neon code (the former were used for reg-reg moves)

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@85764 91177308-0d34-0410-b5e6-96231b3b80d8

Add PseudoSourceValue::mayAlias. It returns true if the object can ever alias any LLVM IR value.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@85762 91177308-0d34-0410-b5e6-96231b3b80d8

Line this up as well.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@85748 91177308-0d34-0410-b5e6-96231b3b80d8

Fix whitespace.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@85747 91177308-0d34-0410-b5e6-96231b3b80d8

Fix a couple more places where we are creating ld / st instructions without memoperands.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@85746 91177308-0d34-0410-b5e6-96231b3b80d8

Make use of imm12 version of Thumb2 ldr / str instructions more aggressively.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@85743 91177308-0d34-0410-b5e6-96231b3b80d8

fix two strange things in the default passmgr:

1. we'd run simplifycfg at the very start, even though
the per function passes have already cleaned this up.

2. In the main per-function pipeline that is interlaced with inlining
   etc, we would do instcombine, jump threading, simplifycfg *before*
   doing SROA.  SROA is much more likely to expose opportunities for
   these passes than they are for SROA, so move SRoA up earlier.

also add some comments.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@85742 91177308-0d34-0410-b5e6-96231b3b80d8

merge phi-merge.ll into phi.ll

I don't know what Dan wants to do with phi-merge-gep.ll, I'll let
him deal with it because instcombine may end up sinking these.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@85739 91177308-0d34-0410-b5e6-96231b3b80d8

when merging two loads, make sure to take the min of their alignment,
not the max.  This didn't matter until the previous patch because
instcombine would refuse to sink loads with differenting alignments.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@85738 91177308-0d34-0410-b5e6-96231b3b80d8

split load sinking out to its own function, like gep sinking.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@85737 91177308-0d34-0410-b5e6-96231b3b80d8

fix a bug noticed by inspection: when instcombine sinks loads through
phis, it didn't preserve the alignment of the load.  This is a missed
optimization of the alignment is high and a miscompilation when the
alignment is low.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@85736 91177308-0d34-0410-b5e6-96231b3b80d8

IPSCCP apparently is not a superset of IPCP, this is bad,
but I'll investigate it separately.  This unbreaks
test/FrontendC/weak_constant.c

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@85735 91177308-0d34-0410-b5e6-96231b3b80d8

convert to filecheck.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@85734 91177308-0d34-0410-b5e6-96231b3b80d8

Improve the other instance of the comment.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@85733 91177308-0d34-0410-b5e6-96231b3b80d8

Add a missing closing parenthesis, and tweak to fit in 80
columns.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@85732 91177308-0d34-0410-b5e6-96231b3b80d8

only run GlobalDCE at -O3 and run it late instead of early.
GlobalOpt already deletes trivially dead functions/globals,
so GlobalDCE only adds values for cycles of dead things.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@85731 91177308-0d34-0410-b5e6-96231b3b80d8

cleanups, switch GlobalDCE to SmallPtrSet instead of std::set

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@85730 91177308-0d34-0410-b5e6-96231b3b80d8

We currently only run ipsccp at LTO time, which is silly.  It subsumes
ipconstprop and doesn't take much time.  Just run it in its place.

This adds a testcase for it, which I plan to expand to cover other
"integration" cases, where we expect the optimizer to be able to
eliminate various things.  Due to phase order issues we've regressed
in a number of areas and integration tests are the only way I see to
prevent this.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@85729 91177308-0d34-0410-b5e6-96231b3b80d8

remove a bunch of locking from LLVMContextImpl.  Since only one thread
can be banging on a context at a time, this isn't needed.  Owen, please
review.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@85728 91177308-0d34-0410-b5e6-96231b3b80d8

improve comment.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@85725 91177308-0d34-0410-b5e6-96231b3b80d8

add a comment about why we don't allow inlining indbr.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@85724 91177308-0d34-0410-b5e6-96231b3b80d8

Fix tests.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@85723 91177308-0d34-0410-b5e6-96231b3b80d8

the verifier shouldn't modify the IR.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@85722 91177308-0d34-0410-b5e6-96231b3b80d8

Reverting 85714, 85715, 85716, which are breaking the build

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@85717 91177308-0d34-0410-b5e6-96231b3b80d8

Add a function to Passes.h to allow clients to create instances
of the ScalarEvolution pass without needing to #include ScalarEvolution.h.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@85716 91177308-0d34-0410-b5e6-96231b3b80d8

Don't #include Pass.h from CallGraph.h.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@85715 91177308-0d34-0410-b5e6-96231b3b80d8

Remove the #include of Pass.h from PassManager.h. This breaks a significant
#include dependency, as frontends commonly pull in PassManager.h.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@85714 91177308-0d34-0410-b5e6-96231b3b80d8

teach ipsccp and ipconstprop that a blockaddress doesn't 'take the address' of a function
in a way that should prevent ip constprop.  This allows clang/test/CodeGen/indirect-goto.c
to pass with the new indirect goto lowering.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@85709 91177308-0d34-0410-b5e6-96231b3b80d8

change llvm::MergeBlockIntoPredecessor to not merge two blocks BB1->BB2
when BB2 has its address taken.  Since it ends up doing BB2->rauw(BB1),
this can cause the address of the entry block to be taken.  Since it is
generally undesirable to nuke blocks whose address is taken, even when
we can, just unconditionally stop this xform.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@85708 91177308-0d34-0410-b5e6-96231b3b80d8

strengthen an assumption: RevectorBlockTo knows that PredBB
ended in an uncond branch because the pass requires BreakCriticalEdges.

However, BCE doesn't eliminate critical adges from indbrs.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@85707 91177308-0d34-0410-b5e6-96231b3b80d8

fix an issue where the verifier would reject a function whose entry
block had its address taken even if the blockaddress was dead.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@85706 91177308-0d34-0410-b5e6-96231b3b80d8

if CostMetrics says to never duplicate some code, don't unswitch a loop.
This prevents unswitching from duplicating indbr's.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@85705 91177308-0d34-0410-b5e6-96231b3b80d8

constant fold indirectbr(blockaddress(%bb)) -> br label %bb.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@85704 91177308-0d34-0410-b5e6-96231b3b80d8

improve x86 codegen support for blockaddress.  We now compile
the testcase into:

_test1:                                                     ## @test1
## BB#0:                                                    ## %entry
leaq L_test1_bb6(%rip), %rax
jmpq *%rax
L_test1_bb:                                                 ## Address Taken
LBB1_1:                                                     ## %bb
movb $1, %al
ret
L_test1_bb6:                                                ## Address Taken
LBB1_2:                                                     ## %bb6
movb $2, %al
ret

Note, it is very very strange that BlockAddressSDNode doesn't carry
around TargetFlags.  Dan, please fix this.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@85703 91177308-0d34-0410-b5e6-96231b3b80d8

pull check for return inst out of loop, never inline a callee that contains
an indirectbr.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@85702 91177308-0d34-0410-b5e6-96231b3b80d8

Fix BlockAddress::replaceUsesOfWithOnConstant to correctly
maintain the block use count in SubclassData.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@85701 91177308-0d34-0410-b5e6-96231b3b80d8

implement linker support for BlockAddress.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@85700 91177308-0d34-0410-b5e6-96231b3b80d8

Revert 85678/85680.  The decision is to stay with the current form of
indirectbr, thus we don't need "blockaddr(@func, null)".  Eliminate it
for simplicity.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@85699 91177308-0d34-0410-b5e6-96231b3b80d8

Use cbz and cbnz instructions.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@85698 91177308-0d34-0410-b5e6-96231b3b80d8

vml[as].f32 cause stalls in following advanced SIMD instructions. Avoid using
them for scalar floating point operations for now.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@85697 91177308-0d34-0410-b5e6-96231b3b80d8

Consolidate test files

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@85696 91177308-0d34-0410-b5e6-96231b3b80d8

Change to use FileCheck

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@85695 91177308-0d34-0410-b5e6-96231b3b80d8

Make tests more explicit about which instructions are expected.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@85694 91177308-0d34-0410-b5e6-96231b3b80d8

Grammar tweak to comments

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@85693 91177308-0d34-0410-b5e6-96231b3b80d8

Make sure PRE doesn't split crit edges from indirectbr.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@85692 91177308-0d34-0410-b5e6-96231b3b80d8

Update test to be more explicit about what instruction sequences are expected for each operation.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@85691 91177308-0d34-0410-b5e6-96231b3b80d8

llvm::SplitEdge should refuse to split an edge from an indirectbr.
Fix CodeGenPrepare to not try to split edges from indirectbr.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@85690 91177308-0d34-0410-b5e6-96231b3b80d8

Update test to be more explicit about what instruction sequences are expected for each operation.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@85689 91177308-0d34-0410-b5e6-96231b3b80d8

update the comment above llvm::SplitCriticalEdge, and make
it abort on IndirectBrInst as describe in the comment.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@85688 91177308-0d34-0410-b5e6-96231b3b80d8

Expand 64-bit logical shift right inline

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@85687 91177308-0d34-0410-b5e6-96231b3b80d8

Expand 64-bit arithmetic shift right inline

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@85685 91177308-0d34-0410-b5e6-96231b3b80d8

Fix a missing newline in the dwarf output code.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@85684 91177308-0d34-0410-b5e6-96231b3b80d8

Make -print-machineinstrs more readable.
 - Be consistent when referring to MachineBasicBlocks: BB#0.
 - Be consistent when referring to virtual registers: %reg1024.
 - Be consistent when referring to unknown physical registers: %physreg10.
 - Be consistent when referring to known physical registers: %RAX
 - Be consistent when referring to register 0: %reg0
 - Be consistent when printing alignments: align=16
 - Print jump table contents.
 - Don't print host addresses, in general.
 - and various other cleanups.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@85682 91177308-0d34-0410-b5e6-96231b3b80d8

Factor out more code into addCommonCodeGenPasses. The JIT wasn't
previously running CodePlacementOpt. Also print headers before
each dump in -print-machineinstrs mode, so that it's clear which
dump is which.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@85681 91177308-0d34-0410-b5e6-96231b3b80d8

adjust a couple xforms to work with null bb's in BlockAddress.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@85680 91177308-0d34-0410-b5e6-96231b3b80d8

Make blockaddress(@func, null) be valid, and make 'deleting a basic
block with a blockaddress still referring to it' replace the invalid
blockaddress with a new blockaddress(@func, null) instead of a
inttoptr(1).

This changes the bitcode encoding format, and still needs codegen
support (this should produce a non-zero value, referring to the entry
block of the function would also be quite reasonable).

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@85678 91177308-0d34-0410-b5e6-96231b3b80d8

Force triple; darwin's ASM syntax differs from linux's.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@85676 91177308-0d34-0410-b5e6-96231b3b80d8

Expand 64 bit left shift inline rather than using the libcall. For now, this
is unconditional. Making it still use the libcall when optimizing for size
would be a good adjustment.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@85675 91177308-0d34-0410-b5e6-96231b3b80d8

Add missing colons for FileCheck.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@85674 91177308-0d34-0410-b5e6-96231b3b80d8

Convert to FileCheck

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@85673 91177308-0d34-0410-b5e6-96231b3b80d8

The universal SDKROOT should only be assigned when hosted. Otherwise the
SDKROOT can refer to the target when we're building for the host.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@85672 91177308-0d34-0410-b5e6-96231b3b80d8

add a comment.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@85671 91177308-0d34-0410-b5e6-96231b3b80d8

Revert r85667. LoopUnroll currently can't call utility functions which
auto-update the DominatorTree because it doesn't keep the DominatorTree
current while it works.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@85670 91177308-0d34-0410-b5e6-96231b3b80d8

Remove redundant code.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@85668 91177308-0d34-0410-b5e6-96231b3b80d8

Merge the enhancements from LoopUnroll's FoldBlockIntoPredecessor into
MergeBlockIntoPredecessor. This makes SimplifyCFG slightly more aggressive,
and makes it unnecessary for LoopUnroll to have its own copy of this code.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@85667 91177308-0d34-0410-b5e6-96231b3b80d8

Rename forgetLoopBackedgeTakenCount to forgetLoop, because it
clears out more information than just the stored backedge taken count.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@85664 91177308-0d34-0410-b5e6-96231b3b80d8

Replace LoopUnrollPass.cpp's custom code-size estimation code using
the new common CodeMetrics code.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@85663 91177308-0d34-0410-b5e6-96231b3b80d8

Simplify this code.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@85662 91177308-0d34-0410-b5e6-96231b3b80d8

Remove an unnecessary #include.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@85661 91177308-0d34-0410-b5e6-96231b3b80d8

Update CMakeLists for recent renames.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@85660 91177308-0d34-0410-b5e6-96231b3b80d8

Rename UnrollLoop.cpp to LoopUnroll.cpp, and LoopUnroll.cpp to
LoopUnrollPass.cpp, for consistency with other passes which are
similarly split.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@85659 91177308-0d34-0410-b5e6-96231b3b80d8

Remove CodeGenLICM. It's largely obsoleted by MachineLICM's new ability
to unfold loop-invariant loads.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@85657 91177308-0d34-0410-b5e6-96231b3b80d8

Make ScalarEvolutionAliasAnalysis slightly more aggressive, by making an
underlying alias call even for non-identified-object values.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@85656 91177308-0d34-0410-b5e6-96231b3b80d8

Reapply r85634, with the bug fixed.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@85655 91177308-0d34-0410-b5e6-96231b3b80d8

When discarding SrcValue information, discard all of it so that code
that uses this information knows to behave conservatively.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@85654 91177308-0d34-0410-b5e6-96231b3b80d8

Fix 80-column violation.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@85653 91177308-0d34-0410-b5e6-96231b3b80d8

Fix warning with gcc-4.0 and signed/unsigned.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@85648 91177308-0d34-0410-b5e6-96231b3b80d8

It's safe to remat t2LDRpci; Add PseudoSourceValue to load / store's to enable more machine licm. More changes coming.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@85643 91177308-0d34-0410-b5e6-96231b3b80d8

Revert 85634. It's breaking consumer-typeset (and others).

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@85641 91177308-0d34-0410-b5e6-96231b3b80d8

Add a target triple so that this test behaves consistently across hosts.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@85640 91177308-0d34-0410-b5e6-96231b3b80d8

Add assertion checks here to turn silent miscompiles into aborts.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@85639 91177308-0d34-0410-b5e6-96231b3b80d8

Don't mark registers dead here when processing nodes with MVT::Flag
results. This works around a problem affecting targets which rely on
MVT::Flag to handle physical register defs.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@85638 91177308-0d34-0410-b5e6-96231b3b80d8

Fix the -mattr line for this test so that it passes on hosts that lack SSSE3.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@85637 91177308-0d34-0410-b5e6-96231b3b80d8

Add a testcase for the recent duplicate PHI elimination changes.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@85636 91177308-0d34-0410-b5e6-96231b3b80d8

Add a comment about a missed opportunity.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@85635 91177308-0d34-0410-b5e6-96231b3b80d8

Optimize around the fact that pred_iterator is slow: instead of sorting
PHI operands by the predecessor order, sort them by the order used by the
first PHI in the block. This is still suffucient to expose duplicates.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@85634 91177308-0d34-0410-b5e6-96231b3b80d8

Updates to the ARM target assembler for llvm-mc per review comments from
Daniel Dunbar.
- Reordered the fields in the ARMOperand Mem struct to make the struct smaller.
Making bool's into 1 bit fields and put the MCExpr* fields adjacent to each
other.
- Fixed a number of places in ARMAsmParser.cpp so they have doxygen comments.
- Change the name of ARMAsmParser::ParseRegister() to MaybeParseRegister and
added the bool ParseWriteBack parameter.
- Changed ARMAsmParser::ParseMemory() to call MaybeParseRegister().
- Added ARMAsmParser::ParseMemoryOffsetReg to factor out parsing the offset of a
memory operand.  And use it for both parsing both preindexed and post indexing
addressing forms in ARMAsmParser::ParseMemory.
- Changed the first argument to ParseShift() to a reference.
- Changed ParseShift() to check for Rrx first and return to reduce nesting.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@85632 91177308-0d34-0410-b5e6-96231b3b80d8

If string field is empty then return NULL.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@85630 91177308-0d34-0410-b5e6-96231b3b80d8

if basic blocks are destroyed while there are *just* BlockAddress' hanging
around, then zap them.  This is analogous to dangling constantexprs hanging
off functions.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@85627 91177308-0d34-0410-b5e6-96231b3b80d8