Remove unneeded checks from configure.ac.

HAVE_{BI,STD,FWD}_ITERATOR and HAVE_NAMESPACES were not used in the code.
bison and flex are no longer used.
CAN_DLOPEN_SELF was never used either.
AC_PROG_LIBTOOL is not needed since we don't use libtool, we only need the
libltdl checks for dlopen.
Add check for AR, it used to be done by AC_PROG_LIBTOOL.
AC_TYPE_SIGNAL is deprecated, follow autoupdate's suggestion and replace with
void.
Remove unused m4 files.
Configure can now be generated using autoconf 2.65 too, without any warnings!

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@94534 91177308-0d34-0410-b5e6-96231b3b80d8

Fix autoconf 2.65 warning (don't use _cv_ inside AC_CACHE_VAL).

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@94533 91177308-0d34-0410-b5e6-96231b3b80d8

Remove warning about non return on a non-void function.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@94532 91177308-0d34-0410-b5e6-96231b3b80d8

eliminate the TargetLowering::UsesGlobalOffsetTable bool, which is
subsumed by TargetLowering::getJumpTableEncoding().  Change uses of
it to be more specific.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@94529 91177308-0d34-0410-b5e6-96231b3b80d8

Now that printPICJumpTableSetLabel is not overloaded,
inline it into its only caller, allowing us to simplify it
and hoist bits out of the loop.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@94528 91177308-0d34-0410-b5e6-96231b3b80d8

Move getJTISymbol from MachineJumpTableInfo to MachineFunction,
which is more convenient, and change getPICJumpTableRelocBaseExpr
to take a MachineFunction to match.

Next, move the X86 code that create a PICBase symbol to
X86TargetLowering::getPICBaseSymbol from
X86MCInstLower::GetPICBaseSymbol, which was an asmprinter specific
library.  This eliminates a 'gross hack', and allows us to
implement X86ISelLowering::getPICJumpTableRelocBaseExpr which now
calls it.

This in turn allows us to eliminate the
X86AsmPrinter::printPICJumpTableSetLabel method, which was the
only overload of printPICJumpTableSetLabel.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@94526 91177308-0d34-0410-b5e6-96231b3b80d8

add a new MachineJumpTableInfo::getJTISymbol method,
use it to implement the default TargetLowering::getPICJumpTableRelocBaseExpr

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@94523 91177308-0d34-0410-b5e6-96231b3b80d8

stub out a new target hook, need some refactoring before I can
implement it.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@94521 91177308-0d34-0410-b5e6-96231b3b80d8

simplify asmprinter: only emit .set directives when entries have
EK_LabelDifference32 kind and the target has .set support.  Simplify
X86AsmPrinter::printPICJumpTableSetLabel to make use of recent helpers.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@94518 91177308-0d34-0410-b5e6-96231b3b80d8

rename printPICJumpTableEntry -> EmitJumpTableEntry,
make it private and non-virtual.  It handles the non-pic
case too, so just use it, simplifying EmitJumpTableInfo.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@94517 91177308-0d34-0410-b5e6-96231b3b80d8

implement X86 @GOTOFF jump table entries with the new EK_Custom32
jump table entry kind, instead of overloading
AsmPrinter::printPICJumpTableEntry.

This has a pretty horrible and inefficient FIXME around how @GOTOFF
is currently smashed into the mcsymbol name, but otherwise this is
much cleaner.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@94516 91177308-0d34-0410-b5e6-96231b3b80d8

add a new MachineBasicBlock::getSymbol method, replacing
the AsmPrinter::GetMBBSymbol.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@94515 91177308-0d34-0410-b5e6-96231b3b80d8

New PBQP solver.

* Fixed a reduction bug which occasionally led to infinite-cost (invalid)
  register allocation solutions despite the existence finite-cost solutions.
* Significantly reduced memory usage (>50% reduction).
* Simplified a lot of the solver code.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@94514 91177308-0d34-0410-b5e6-96231b3b80d8

Fix the the ceiling-division used in computing the MaxBECount so that it doesn't
have trouble with an intermediate add overflowing. Also, be more conservative
about the case where the induction variable in an SLT loop exit can step past
the RHS of the SLT and overflow in a single step.

Make getSignedRange more aggressive, to recover for some common cases which
the above fixes pessimized.

This addresses rdar://7561161.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@94512 91177308-0d34-0410-b5e6-96231b3b80d8

don't bother setting the AsmPrinter::MF ivar, now that
AsmPrinter::SetupMachineFunction sets it.  Note that systemz
and msp430 didn't.  Yay for reduced inconsistency! :)

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@94510 91177308-0d34-0410-b5e6-96231b3b80d8

make MachineFunction keep track of its ID and make
MachineFunctionAnalysis dole them out, instead of having
AsmPrinter do both.  Have the AsmPrinter::SetupMachineFunction
method set the 'AsmPrinter::MF' variable.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@94509 91177308-0d34-0410-b5e6-96231b3b80d8

this hook should be const.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@94508 91177308-0d34-0410-b5e6-96231b3b80d8

Add a comment about a missed opportunity.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@94507 91177308-0d34-0410-b5e6-96231b3b80d8

Print empty and full sets specially.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@94506 91177308-0d34-0410-b5e6-96231b3b80d8

Add support for target-specific 32-bit custom-lowered
jump table entries.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@94505 91177308-0d34-0410-b5e6-96231b3b80d8

Unbreak MSVC/CMake build.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@94502 91177308-0d34-0410-b5e6-96231b3b80d8

make jit jump table emission be based on the EntryKind instead of magic variables.
JITInfo::getPICJumpTableEntry can probably be removed now, but I don't plan to do
this.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@94501 91177308-0d34-0410-b5e6-96231b3b80d8

switch jump table entry emission to be based on EntryKind
instead of magic variables.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@94500 91177308-0d34-0410-b5e6-96231b3b80d8

In mem2reg, for all alloca/stores that get promoted where the alloca has an associated llvm.dbg.declare instrinsic, insert an llvm.dbg.var intrinsic before each store.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@94493 91177308-0d34-0410-b5e6-96231b3b80d8

Add MDNode::getIfExists(), an efficient way to determine if a value is used by metadata (since metadata does not appear in a value's use list)

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@94492 91177308-0d34-0410-b5e6-96231b3b80d8

Assert when debug intrinsic insert functions are passed empty arguments

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@94491 91177308-0d34-0410-b5e6-96231b3b80d8

Implement cond ? -1 : 0 with sbb.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@94490 91177308-0d34-0410-b5e6-96231b3b80d8

Accept immediate as value of a dbg_value.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@94489 91177308-0d34-0410-b5e6-96231b3b80d8

Re-enable unit tests disabled in r94164 by telling GTest about the
lack of RTTI.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@94484 91177308-0d34-0410-b5e6-96231b3b80d8

Added the implementation of the Intel-specific
TargetAsmLexer.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@94482 91177308-0d34-0410-b5e6-96231b3b80d8

Generate DEBUG_VALUE comments on x86.  The (limited)
dbg.declare's we currently generate go through both
register allocators without perturbing the results.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@94480 91177308-0d34-0410-b5e6-96231b3b80d8

Added the TargetAsmLexer implementation for AT&T syntax.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@94479 91177308-0d34-0410-b5e6-96231b3b80d8

use findDebugLoc in more places.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@94477 91177308-0d34-0410-b5e6-96231b3b80d8

Minor jump table cleanup.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@94475 91177308-0d34-0410-b5e6-96231b3b80d8

in 32-bit pic mode for targets with a GOT, x86 emits jump table
entries with @GOTOFF whih is EK_GPRel32BlockAddress.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@94474 91177308-0d34-0410-b5e6-96231b3b80d8

fix quoting problem jim noticed!

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@94472 91177308-0d34-0410-b5e6-96231b3b80d8

Rearrange handling of jump tables.  Highlights:
1. MachineJumpTableInfo is now created lazily for a function the first time
   it actually makes a jump table instead of for every function.
2. The encoding of jump table entries is now described by the
   MachineJumpTableInfo::JTEntryKind enum.  This enum is determined by the
   TLI::getJumpTableEncoding() hook, instead of by lots of code scattered
   throughout the compiler that "knows" that jump table entries are always
   32-bits in pic mode (for example).
3. The size and alignment of jump table entries is now calculated based on
   their kind, instead of at machinefunction creation time.

Future work includes using the EntryKind in more places in the compiler,
eliminating other logic that "knows" the layout of jump tables in various
situations.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@94470 91177308-0d34-0410-b5e6-96231b3b80d8

prep work to support a future where getJumpTableInfo will return
a null pointer for functions with no jump tables.  No functionality
change.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@94469 91177308-0d34-0410-b5e6-96231b3b80d8

add a method to get the alignment of an integer type even
when we don't have one laying around.  Useful if you don't
have an llvmcontext handy.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@94468 91177308-0d34-0410-b5e6-96231b3b80d8

Make it SP, LR, PC for GPR Register Class instead of LR, SP, PC.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@94465 91177308-0d34-0410-b5e6-96231b3b80d8

eliminate redundant argument to EmitJumpTableInfo

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@94464 91177308-0d34-0410-b5e6-96231b3b80d8

Implemented ARMInstPrinter::printThumbS4ImmOperand().

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@94457 91177308-0d34-0410-b5e6-96231b3b80d8

Implemented the dialect decision logic for the X86
TargetAsmLexer.  Dialect-specific lexing code will
be placed in the functions LexTokenATT() and
LexTokenIntel().

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@94456 91177308-0d34-0410-b5e6-96231b3b80d8

Fixed the order of GPR RegisterClass regs to be: ..., R10, R11, R12, ...

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@94455 91177308-0d34-0410-b5e6-96231b3b80d8

Fix the bitcode reader to deserialize nuw/nsw/etc. bits properly in the case
of a forward-reference, which doesn't use an "abbrev" encoding.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@94454 91177308-0d34-0410-b5e6-96231b3b80d8

mcstreamerize gprel32 emission.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@94452 91177308-0d34-0410-b5e6-96231b3b80d8

Remove check for an impossible condition: the condition of the while loop has
already checked that TmpBB->getSinglePredecessor() is non-null.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@94451 91177308-0d34-0410-b5e6-96231b3b80d8

mcize the non-gprel cases of AsmPrinter::printPICJumpTableEntry

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@94450 91177308-0d34-0410-b5e6-96231b3b80d8

handle the _set_ symbol with an MCSymbol.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@94449 91177308-0d34-0410-b5e6-96231b3b80d8

rename MAI::PICJumpTableDirective to MAI::GPRel32Directive to
make it clear what it is, instead of how it is used.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@94448 91177308-0d34-0410-b5e6-96231b3b80d8

pull the non-pic jump table case out of printPICJumpTableEntry
and MCize the non-pic case.  Now printPICJumpTableEntry really
is just about printing PIC entries.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@94446 91177308-0d34-0410-b5e6-96231b3b80d8

remove JumpTableDirective, it is always null.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@94445 91177308-0d34-0410-b5e6-96231b3b80d8

no need to implement these.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@94443 91177308-0d34-0410-b5e6-96231b3b80d8

mcize jump table symbol manipulation.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@94441 91177308-0d34-0410-b5e6-96231b3b80d8

sink an arm specific method out of asmprinter into the ARMAsmPrinter and
rename it to avoid shadowing.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@94440 91177308-0d34-0410-b5e6-96231b3b80d8

remove dead code: the x86 target never sets usesGlobalOffsetTable,
even on x86-32/elf which uses a GOT.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@94439 91177308-0d34-0410-b5e6-96231b3b80d8

wirte up .file and .file to the mc asmparser.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@94438 91177308-0d34-0410-b5e6-96231b3b80d8

mcstreamerize .file and .file.  This also fixes an issue where the
normal form of .file would fail if the filename had a weird character
in it.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@94437 91177308-0d34-0410-b5e6-96231b3b80d8

emit ELF .type directives through MCStreamer instead of doing it textually.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@94436 91177308-0d34-0410-b5e6-96231b3b80d8

add symbol attribute support for the ELF .type directive.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@94435 91177308-0d34-0410-b5e6-96231b3b80d8

Change Value::getUnderlyingObject to have the MaxLookup value specified as a
parameter with a default value, instead of just hardcoding it in the
implementation.  The limit of MaxLookup = 6 was introduced in r69151 to fix
a performance problem with O(n^2) behavior in instcombine, but the scalarrepl
pass is relying on getUnderlyingObject to go all the way back to an AllocaInst.
Making the limit part of the method signature makes it clear that by default
the result is limited and should help avoid similar problems in the future.
This fixes pr6126.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@94433 91177308-0d34-0410-b5e6-96231b3b80d8

Revert r94260 until findDbgDeclare() is made more efficient

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@94432 91177308-0d34-0410-b5e6-96231b3b80d8

Update test for darwin.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@94421 91177308-0d34-0410-b5e6-96231b3b80d8

add a comment

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@94417 91177308-0d34-0410-b5e6-96231b3b80d8

emit the .size directive for global variables on ELF through
mcstreamer.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@94416 91177308-0d34-0410-b5e6-96231b3b80d8

we removed support for darwin8 tools.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@94414 91177308-0d34-0410-b5e6-96231b3b80d8

all supported target now have aligned common support.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@94413 91177308-0d34-0410-b5e6-96231b3b80d8

Remove support for i386 tiger tools for aligned common symbols.
Previously we would just silently miscompile code that used aligned
common's, now at least you'll get a build error.  tiger-ppc already
triggered the build error because it didn't have a version of this
logic.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@94412 91177308-0d34-0410-b5e6-96231b3b80d8

don't set value to its default.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@94411 91177308-0d34-0410-b5e6-96231b3b80d8

coff targets support alignment on .comm

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@94410 91177308-0d34-0410-b5e6-96231b3b80d8

ARM does accept the .comm directive alignment.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@94408 91177308-0d34-0410-b5e6-96231b3b80d8

Fix autoconf llvm srcdir location for generic projects.

Patch by Torvald Riegel!

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@94405 91177308-0d34-0410-b5e6-96231b3b80d8

Fix PR6134.
We are not emitting alignments on Darwin for "bar". Not sure what is the
correct way to do it.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@94400 91177308-0d34-0410-b5e6-96231b3b80d8

Attempt to unbreak test on Linux. Chris, please check.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@94399 91177308-0d34-0410-b5e6-96231b3b80d8

This example requires RTTI.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@94398 91177308-0d34-0410-b5e6-96231b3b80d8

linux/ppc does use alignment in bytes, not pow-2.  This fixes PR6129.
It looks like linux/arm and linux/mips have the same setting, which
are probably wrong.  Someone who cares about ARM and MIPS should
investigate with the testcase in PR6129.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@94381 91177308-0d34-0410-b5e6-96231b3b80d8

don't reset the default.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@94380 91177308-0d34-0410-b5e6-96231b3b80d8

make -fno-rtti the default unless a directory builds with REQUIRES_RTTI.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@94378 91177308-0d34-0410-b5e6-96231b3b80d8

mark some libraries that currently require RTTI.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@94377 91177308-0d34-0410-b5e6-96231b3b80d8

libs that need EH need RTTI.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@94376 91177308-0d34-0410-b5e6-96231b3b80d8

ENABLE_EXPENSIVE_CHECKS shouldn't know how rtti is enabled, let REQUIRES_RTTI handle it.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@94375 91177308-0d34-0410-b5e6-96231b3b80d8

reassociate should do this.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@94374 91177308-0d34-0410-b5e6-96231b3b80d8

add a note.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@94373 91177308-0d34-0410-b5e6-96231b3b80d8

just remove this test, it is not reduced, is not clear what its testing for and
it is dying due to fragility in the asmprinter .s comments.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@94372 91177308-0d34-0410-b5e6-96231b3b80d8

this test has been failing or a long time, just disable it for now to get
back to green.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@94371 91177308-0d34-0410-b5e6-96231b3b80d8

fix some issues where we weren't emitting enough newlines.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@94370 91177308-0d34-0410-b5e6-96231b3b80d8

when emitting DIEs, emit the comment on the same line as the directive.
This fixes FrontendObjC/2009-11-30-Objc-ID.m

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@94369 91177308-0d34-0410-b5e6-96231b3b80d8

move PR5945 here.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@94350 91177308-0d34-0410-b5e6-96231b3b80d8

fix a parsing problem on instructions like:
movw $8, (_cost_table_-L97$pb)+66(%eax)

After the parens, we could still have a binop.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@94345 91177308-0d34-0410-b5e6-96231b3b80d8

This corrects an error in the type of the Llvm.dispose_context function.
Patch by James Woodyatt!

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@94343 91177308-0d34-0410-b5e6-96231b3b80d8

It seems better to scalarize vectors of size 1 instead of widening them.
Add support to widen SETCC.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@94342 91177308-0d34-0410-b5e6-96231b3b80d8

change the canonical form of "cond ? -1 : 0" to be
"sext cond" instead of a select.  This simplifies some instcombine
code, matches the policy for zext (cond ? 1 : 0 -> zext), and allows
us to generate better code for a testcase on ppc.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@94339 91177308-0d34-0410-b5e6-96231b3b80d8

Improved widening loads by adding support for wider loads if
the alignment allows.  Fixed a bug where we didn't use a
vector load/store for PR5626.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@94338 91177308-0d34-0410-b5e6-96231b3b80d8

fix a potential overflow issue Eli pointed out.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@94336 91177308-0d34-0410-b5e6-96231b3b80d8

Speculatively revert r94322 to see if it fixes darwin selfhost buildbot.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@94331 91177308-0d34-0410-b5e6-96231b3b80d8

third bug from PR6119: the xor dupe extension allows
for arbitrary terminators in predecessors, don't assume
it is a conditional or uncond branch.  The testcase shows
an example where they can happen with switches.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@94323 91177308-0d34-0410-b5e6-96231b3b80d8

Teach DAE that even though it can't modify the function signature of an
externally visible function, it can still find all callers of it and replace
the parameters to a dead argument with undef.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@94322 91177308-0d34-0410-b5e6-96231b3b80d8

add an early out to ProcessBranchOnXOR to speed it up,
handle the case when we can infer an input to the xor
from all inputs that agree, instead of going into an
infinite loop.  Another part of PR6199

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@94321 91177308-0d34-0410-b5e6-96231b3b80d8

fix a crash in jump threading, PR6119

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@94319 91177308-0d34-0410-b5e6-96231b3b80d8

implement a simple instcombine xform that has been in the
readme forever.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@94318 91177308-0d34-0410-b5e6-96231b3b80d8