[x86] Support i386-*-*-code16 triple for emitting 16-bit code

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@199648 91177308-0d34-0410-b5e6-96231b3b80d8
[x86] Infer disassembler mode from SubtargetInfo feature bits

Aside from cleaning up the code, this also adds support for the -code16
environment and actually enables the MODE_16BIT mode that was previously
not accessible.

There is no point adding any testing for 16-bit yet though; basically
nothing will work because we aren't handling the OpSize prefix correctly
for 16-bit mode.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@199649 91177308-0d34-0410-b5e6-96231b3b80d8
[x86] Fix 16-bit handling of OpSize bit

When disassembling in 16-bit mode the meaning of the OpSize bit is
inverted. Instructions found in the IC_OPSIZE context will actually
*not* have the 0x66 prefix, and instructions in the IC context will
have the 0x66 prefix. Make use of the existing special-case handling
for the 0x66 prefix being in the wrong place, to cope with this.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@199650 91177308-0d34-0410-b5e6-96231b3b80d8
[x86] Fix disassembly of callw instruction

Not quite sure why this was marked isAsmParserOnly, but it means that the
disassembler can't see it either.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@199651 91177308-0d34-0410-b5e6-96231b3b80d8
[x86] Rename MOVSD/STOSD/LODSD/OUTSD to MOVSL/STOSL/LODSL/OUTSL

The disassembler has a special case for 'L' vs. 'W' in its heuristic for
checking for 32-bit and 16-bit equivalents. We could expand the heuristic,
but better just to be consistent in using the 'L' suffix.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@199652 91177308-0d34-0410-b5e6-96231b3b80d8
[x86] Fix 16-bit disassembly of JCXZ/JECXZ

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@199653 91177308-0d34-0410-b5e6-96231b3b80d8
[x86] Fix disassembly of MOV16ao16 et al.

The addition of IC_OPSIZE_ADSIZE in r198759 wasn't quite complete. It
also turns out to have been unnecessary. The disassembler handles the
AdSize prefix for itself, and doesn't care about the difference between
(e.g.) MOV8ao8 and MOB8ao8_16 definitions. So just let them coexist and
don't worry about it.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@199654 91177308-0d34-0410-b5e6-96231b3b80d8
Track multiple stores per object when using AA in ScheduleDAGInstrs

When using AA to break false chain dependencies, we need to track multiple
stores per object in ScheduleDAGInstrs. Historically, we tracked potential alias
chains at the object level, and so all loads of an object would retain
dependencies on any store to that object. With AA, however, this is not
sufficient: non-overlapping stores and loads to the same object all need to be
tested for dependencies separately, we cannot only test all loads to an object
against only the last store (see PR18497 for an explicit example).

To mitigate any unwelcome compile-time impact when not using AA, only one store
is kept in the list per object when not using AA.

This, along with a stack coloring change to come shortly, will provide a test
case, fix PR18497 (and allow LLVM to compile itself using -enable-aa-sched-mi
on x86-64).

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@199657 91177308-0d34-0410-b5e6-96231b3b80d8
Update IR when merging slots in stack coloring

The way that stack coloring updated MMOs when merging stack slots, while
correct, is suboptimal, and is incompatible with the use of AA during
instruction scheduling. The solution, which involves the use of const_cast (and
more importantly, updating the IR from within an MI-level pass), obviously
requires some explanation:

When the stack coloring pass was originally committed, the code in
ScheduleDAGInstrs::buildSchedGraph tracked possible alias sets by using
GetUnderlyingObject, and all load/store and store/store memory control
dependencies where added between SUs at the object level (where only one
object, that returned by GetUnderlyingObject, was used to identify the object
associated with each MMO). When stack coloring merged stack slots, it would
replace MMOs derived from the remapped alloca with the alloca with which the
remapped alloca was being replaced. Because ScheduleDAGInstrs only used single
objects, and tracked alias sets at the object level, this was a fine solution.

In r169744, (Andy and) I updated the code in ScheduleDAGInstrs to use
GetUnderlyingObjects, and track alias sets using, potentially, multiple
underlying objects for each MMO. This was done, primarily, to provide the
ability to look through PHIs, and provide better scheduling for
induction-variable-dependent loads and stores inside loops. At this point, the
MMO-updating code in stack coloring became suboptimal, because it would clear
the MMOs for (i.e. completely pessimize) all instructions for which r169744
might help in scheduling. Updating the IR directly is the simplest fix for this
(and the one with, by far, the least compile-time impact), but others are
possible (we could give each MMO a small vector of potential values, or make
use of a remapping table, constructed from MFI, inside ScheduleDAGInstrs).

Unfortunately, replacing all MMO values derived from the remapped alloca with
the base replacement alloca fundamentally breaks our ability to use AA during
instruction scheduling (which is critical to performance on some targets). The
reason is that the original MMO might have had an offset (either constant or
dynamic) from the base remapped alloca, and that offset is not present in the
updated MMO. One possible way around this would be to use
GetPointerBaseWithConstantOffset, and update not only the MMO's value, but also
its offset based on the original offset. Unfortunately, this solution would
only handle constant offsets, and for safety (because AA is not completely
restricted to deducing relationships with constant offsets), we would need to
clear all MMOs without constant offsets over the entire function. This would be
an even worse pessimization than the current single-object restriction. Any
other solution would involve passing around a vector of remapped allocas, and
teaching AA to use it, introducing additional complexity and overhead into AA.

Instead, when remapping an alloca, we replace all IR uses of that alloca as
well (optionally inserting a bitcast as necessary). This is even more efficient
that the old MMO-updating code in the stack coloring pass (because it removes
the need to call GetUnderlyingObject on all MMO values), removes the
single-object pessimization in the default configuration, and enables the
correct use of AA during instruction scheduling (all without any additional
overhead).

LLVM now no longer miscompiles itself on x86_64 when using -enable-misched
-enable-aa-sched-mi -misched-bottomup=0 -misched-topdown=0 -misched=shuffle!
Fixed PR18497.

Because the alloca replacement is now done at the IR level, unless the MMO
directly refers to the remapped alloca, the change cannot be seen at the MI
level. As a result, there is no good way to fix test/CodeGen/X86/pr14090.ll.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@199658 91177308-0d34-0410-b5e6-96231b3b80d8
Fix misched-aa-colored.ll to require asserts.

-misched=shuffle is NDEBUG only. Maybe we should change that.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@199659 91177308-0d34-0410-b5e6-96231b3b80d8
Fix misched-aa-colored.ll to require asserts (trying again)

Perhaps it needs to be in caps.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@199661 91177308-0d34-0410-b5e6-96231b3b80d8
Whitespace.

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[CMake] LLVMProcessSources.cmake: Add include(CMakeParseArguments).

I didn't realize that cmake_parse_arguments() would require explicit inclusion.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@199674 91177308-0d34-0410-b5e6-96231b3b80d8
Remove the useless pseudo instructions VDUPfdf and VDUPfqf, replacing them with patterns to match VDUPLN.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@199675 91177308-0d34-0410-b5e6-96231b3b80d8
Allow SMUL_LOHI and UMUL_LOHI to be narrow to MUL on targets where MUL is Custom rather than Legal.  Even if the target is doing some kind of expansion for MUL, it's pretty much guaranteed to be more efficent than whatever it does for SMUL_LOHI or UMUL_LOHI!


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@199678 91177308-0d34-0410-b5e6-96231b3b80d8
Revert "Debug info: On ARM ensure that the data sections come before the"
Cut back on the cargo cult. The order of __DATA sections doesn't affect
generated code.

This reverts commit r197922.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@199680 91177308-0d34-0410-b5e6-96231b3b80d8
Debug info: On ARM ensure that all __TEXT sections come before the
optional DWARF sections, so compiling with -g does not result in
different code being generated for PC-relative loads.

This is reapplying a diet r197922 (__TEXT-only).

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@199681 91177308-0d34-0410-b5e6-96231b3b80d8
[X86] Teach how to combine a vselect into a movss/movsd

Add target specific rules for combining vselect dag nodes into movss/movsd
when possible.

If the vector type of the vselect dag node in input is either MVT::v4i13 or
MVT::v4f32, then try to fold according to rules:

  1) fold (vselect (build_vector (0, -1, -1, -1)), A, B) -> (movss A, B)
  2) fold (vselect (build_vector (-1, 0, 0, 0)), A, B) -> (movss B, A)

If the vector type of the vselect dag node in input is either MVT::v2i64 or
MVT::v2f64 (and we have SSE2), then try to fold according to rules:

  3) fold (vselect (build_vector (0, -1)), A, B) -> (movsd A, B)
  4) fold (vselect (build_vector (-1, 0)), A, B) -> (movsd B, A)



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@199683 91177308-0d34-0410-b5e6-96231b3b80d8
Update StackProtector when coloring merges stack slots

StackProtector keeps a ValueMap of alloca instructions to layout kind tags for
use by PEI and other later passes. When stack coloring replaces one alloca with
a bitcast to another one, the key replacement in this map does not work.
Instead, provide an interface to manage this updating directly. This seems like
an improvement over the old behavior, where the layout map would not get
updated at all when the stack slots were merged. In practice, however, there is
likely no observable difference because PEI only did anything special with
'large array' kinds, and if one large array is merged with another, than the
replacement should already have been a large array.

This is an attempt to unbreak the clang-x86_64-darwin11-RA builder.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@199684 91177308-0d34-0410-b5e6-96231b3b80d8
To allow the X86 verbose assembly to print its informative comments
when used with symbolic disassembly, add a check that the operand
is an immediate and has not been symbolicated to MCExpr operand.

I’m trying to enable the ‘C’ disassembly API option
LLVMDisassembler_Option_SetInstrComments for darwin’s
otool(1) that uses the llvm disassembler API.  The problem is
that the disassembler API can change an immediate operand to
an MCExpr operand if it symbolicates it with the call backs.
And if it does the code in llvm::EmitAnyX86InstComments()
will crash when it assumes these operands are immediates.

The fix for this is very straight forward to just protect the call
to getImm() with a check of isImm().  So if the immediate for
an instruction is symbolicated it simply doesn’t get the X86
verbose assembly comments:

% otool -tV test_asm.o
test_asm.o:
(__TEXT,__text) section
_t1:
0000000000000000	vpshufd	$_t1, %xmm1, %xmm0
0000000000000005	retq
0000000000000006	nopw	%cs:_t1(%rax,%rax)
_t2:
0000000000000010	vpshufd	$-0x1, %xmm0, %xmm0     ## xmm0 = xmm0[3,3,3,3]
0000000000000015	retq
0000000000000016	nopw	%cs:_t1(%rax,%rax)
_t3:
0000000000000020	vpshufd	$_t1, %xmm1, %xmm0
0000000000000025	retq
0000000000000026	nopw	%cs:_t1(%rax,%rax)
_t4:
0000000000000030	vpshufd	$0x2d, %xmm0, %xmm0     ## xmm0 = xmm0[1,3,2,0]
0000000000000035	retq

The fact that the immediate $0x0 is being symbolicated at
all in this case is a different problem which my next patch
will address.

rdar://10989286


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@199697 91177308-0d34-0410-b5e6-96231b3b80d8