Only create a canonical IV for backedge taken count if it will
actually be used by LinearFunctionTestReplace. And some related
cleanup, preparing to reduce dependence on canonical IVs.
No significant effect on x86 or arm in the test-suite.

llvm-svn: 130799

Even if the subprogram is going to use AT_specification, emit DW_AT_MIPS_linkage_name. This helps gdb and fixes var-path-expr.exp regression reported by gdb testsuite.

llvm-svn: 130794

(and should thus never be done).
 - Should fix a crash on win32.

llvm-svn: 130793

<rdar://problem/8460511>

llvm-svn: 130791

Register coalescing can sometimes create live ranges that end in the middle of a
basic block without any killing instruction. When SplitKit detects this, it will
repair the live range by shrinking it to its uses.

Live range splitting also needs to know about this. When the range shrinks so
much that it becomes allocatable, live range splitting fails because it can't
find a good split point. It is paranoid about making progress, so an allocatable
range is considered an error.

The coalescer should really not be creating these bad live ranges. They appear
when coalescing dead copies.

llvm-svn: 130787

max(a,b) >= a -> true.  According to my super-optimizer, these are
by far the most common simplifications (of the -instsimplify kind)
that occur in the testsuite and aren't caught by -std-compile-opts.

llvm-svn: 130780

llvm-svn: 130779

llvm-svn: 130778

llvm-svn: 130774

llvm-svn: 130769

llvm-svn: 130766

it's possible.

llvm-svn: 130764

llvm-svn: 130763

llvm-svn: 130761

If the front end has emitted llvm.dbg.cu and other debug info anchors (clang does it now) then use them directly. This saves one scan of entire module, to collect debug info, which in turns saves few machine cycles at compile time.

llvm-svn: 130759

llvm-svn: 130756

llvm-svn: 130755

llvm-svn: 130754

llvm-svn: 130749

string template.

Fixes rdar://8493866

llvm-svn: 130747

model constants which can be added to base registers via add-immediate
instructions which don't require an additional register to materialize
the immediate.

llvm-svn: 130743

Other parts of the SelectionDAG framework assume that targets use their pointer type for vector indices.  Make the vector unrolling code respect that.

llvm-svn: 130733

Scanning entire basic block may be too expensive in terms of compile time. Instead, just use whatever location info first non-phi instruction has.

llvm-svn: 130729

llvm-svn: 130718

llvm-svn: 130716

llvm-svn: 130715

Def operands may also have an <undef> flag, but that just means that a
sub-register redef doesn't actually read the super-register. For physical
registers, it has no meaning.

llvm-svn: 130714

llvm-svn: 130713

llvm-svn: 130712

a vector compare, generate a vector result rather than i1 (and crashing).

llvm-svn: 130706

llvm-svn: 130705

This works around a limitation in gdb which is reported by following inherit.exp test failures from gdb testsuite.

gdb.cp/inherit.exp: print g_vB.vB::vb
gdb.cp/inherit.exp: print g_vB.vB::vx
gdb.cp/inherit.exp: print g_vC.vC::vc
gdb.cp/inherit.exp: print g_vC.vC::vx
gdb.cp/inherit.exp: print g_vD.vB::vb
...

llvm-svn: 130702

llvm-svn: 130695

This automagically provides a transform noticed by my super-optimizer
as occurring quite often: "rem x, (select cond, x, 1)" -> 0.

llvm-svn: 130694

llvm-svn: 130693

llvm-svn: 130692

llvm-svn: 130691

llvm-svn: 130690

llvm-svn: 130688

When an interfering live range ends at a dead slot index between two
instructions, make sure that the inserted copy instruction gets a slot index
after the dead ones. This makes it possible to avoid the interference.

Ideally, there shouldn't be interference ending at a deleted instruction, but
physical register coalescing can sometimes do that to sub-registers.

This fixes PR9823.

llvm-svn: 130687