Calls that use register mask operands don't have implicit defs for
returned values.  The register mask operand handles the call clobber,
but it always behaves like a set of dead defs.

Add live implicit defs for any implicitly defined physregs that are
actually used.

llvm-svn: 149715

llvm-svn: 149709

SelectionDAG has 4 different ways of passing physreg defs to users.
Collect all of the uses at the same time, and pass all of them to
MI->setPhysRegsDeadExcept() to mark the remaining defs dead.

The setPhysRegsDeadExcept() function will soon add the required
implicit-defs to instructions with register mask operands.

llvm-svn: 149708

It doesn't seem worthwhile to give meaning to a NULL register mask
pointer. It complicates all the code using register mask operands.

llvm-svn: 149646

The live range of the source register may be extended when a redundant
copy is eliminated. Make sure any kill flags between the two copies are
cleared.

This fixes PR11765.

llvm-svn: 149069

Register masks will be used as a compact representation of large clobber
lists.  Currently, an x86 call instruction has some 40 operands
representing call-clobbered registers.  That's more than 1kB of useless
operands per call site.

A register mask operand references a bit mask of call-preserved
registers, everything else is clobbered.  The bit mask will typically
come from TargetRegisterInfo::getCallPreservedMask().

By abandoning ImplicitDefs for call-clobbered registers, it also becomes
possible to share call instruction descriptions between calling
conventions, and we can get rid of the WINCALL* instructions.

This patch introduces the new operand kind.  Future patches will add
RegMask support to target-independent passes before finally the fixed
clobber lists can be removed from call instruction descriptions.

llvm-svn: 148250

of several newly un-defaulted switches. This also helps optimizers
(including LLVM's) recognize that every case is covered, and we should
assume as much.

llvm-svn: 147861

llvm-svn: 147855

  to finalize MI bundles (i.e. add BUNDLE instruction and computing register def
  and use lists of the BUNDLE instruction) and a pass to unpack bundles.
- Teach more of MachineBasic and MachineInstr methods to be bundle aware.
- Switch Thumb2 IT block to MI bundles and delete the hazard recognizer hack to
  prevent IT blocks from being broken apart.

llvm-svn: 146542

clients to decide whether to look inside bundled instructions and whether
the query should return true if any / all bundled instructions have the
queried property.

llvm-svn: 146168

generator to it. For non-bundle instructions, these behave exactly the same
as the MC layer API.

For properties like mayLoad / mayStore, look into the bundle and if any of the
bundled instructions has the property it would return true.
For properties like isPredicable, only return true if *all* of the bundled
instructions have the property.
For properties like canFoldAsLoad, isCompare, conservatively return false for
bundles.

llvm-svn: 146026

llvm-svn: 146004

This flag is used when bundling machine instructions.  It indicates
whether the operand reads a value defined inside or outside its bundle.

llvm-svn: 145997

1. Added opcode BUNDLE
2. Taught MachineInstr class to deal with bundled MIs
3. Changed MachineBasicBlock iterator to skip over bundled MIs; added an iterator to walk all the MIs
4. Taught MachineBasicBlock methods about bundled MIs

llvm-svn: 145975

When this field is true it means that the load is from constant (runt-time or compile-time) and so can be hoisted from loops or moved around other memory accesses

llvm-svn: 144100

llvm-svn: 143646

Treat objc selector reference globals as invariant so that MachineLICM can hoist them out of loops.  Fixes <rdar://problem/6027699>

llvm-svn: 143600

llvm-svn: 141842

Most instructions have some requirements for their register operands.
Usually, this is expressed as register class constraints in the
MCInstrDesc, but for inline assembly the constraints are encoded in the
flag words.

llvm-svn: 141835

llvm-svn: 141834

The inline asm operand constraint is initially encoded in the virtual
register for the operand, but that register class may change during
coalescing, and the original constraint is lost.

Encode the original register class as part of the flag word for each
inline asm operand.  This makes it possible to recover the actual
constraint required by inline asm, just like we can for normal
instructions.

llvm-svn: 141833

llvm-svn: 140767

The function needs to scan the implicit operands anyway, so no
performance is won by caching the number of implicit operands added to
an instruction.

This also fixes a bug when adding operands after an implicit operand has
been added manually.  The NumImplicitOps count wasn't kept up to date.

MachineInstr::addOperand() will now consistently place all explicit
operands before all the implicit operands, regardless of the order they
are added.  It is possible to change an MI opcode and add additional
explicit operands.  They will be inserted before any existing implicit
operands.

The only exception is inline asm instructions where operands are never
reordered.  This is because of a hack that marks explicit clobber regs
on inline asm as <implicit-def> to please the fast register allocator.
This hack can go away when InstrEmitter and FastIsel can add exact
<dead> flags to physreg defs.

llvm-svn: 140744

llvm-svn: 138773

llvm-svn: 138437

Normally, a partial register def is treated as reading the
super-register unless it also defines the full register like this:

  %vreg110:sub_32bit<def> = COPY %vreg77:sub_32bit, %vreg110<imp-def>

This patch also uses the <undef> flag on partial defs to recognize
non-reading operands:

  %vreg110:sub_32bit<def,undef> = COPY %vreg77:sub_32bit

This fixes a subtle bug in RegisterCoalescer where LIS->shrinkToUses
would treat a coalesced copy as still reading the register, extending
the live range artificially.

My test case only works when I disable DCE so a dead copy is left for
RegisterCoalescer, so I am not including it.

<rdar://problem/9967101>

llvm-svn: 138018

llvm-svn: 136916

If known DebugLocs do not match then two DBG_VALUE machine instructions are not identical. For example,

        DBG_VALUE 3.310000e+02, 0, !"ds"; dbg:sse.stepfft.c:138:18 @[ sse.stepfft.c:32:10 ]
        DBG_VALUE 3.310000e+02, 0, !"ds"; dbg:sse.stepfft.c:138:18 @[ sse.stepfft.c:31:10 ]

These two MIs represent identical value, 3.31...,  for one variable, ds, but they are not identical because the represent two separate instances of inlined variable "ds". 

llvm-svn: 134620

Add a MI->emitError() method that the backend can use to report errors
related to inline assembly. Call it from X86FloatingPoint.cpp when the
constraints are wrong.

This enables proper clang diagnostics from the backend:

$ clang -c pr30848.c
pr30848.c:5:12: error: Inline asm output regs must be last on the x87 stack
  __asm__ ("" : "=u" (d));  /* { dg-error "output regs" } */
           ^
1 error generated.

llvm-svn: 134307

llvm-svn: 134287

sink them into MC layer.
- Added MCInstrInfo, which captures the tablegen generated static data. Chang
TargetInstrInfo so it's based off MCInstrInfo.

llvm-svn: 134021

Both become <earlyclobber> defs on the INLINEASM MachineInstr, but we
now use two different asm operand kinds.

The new Kind_Clobber is treated identically to the old
Kind_RegDefEarlyClobber for now, but x87 floating point stack inline
assembly does care about the difference.

This will pop a register off the stack:

  asm("fstp %st" : : "t"(x) : "st");

While this will pop the input and push an output:

  asm("fst %st" : "=&t"(r) : "t"(x));

We need to know if ST0 was a clobber or an output operand, and we can't
depend on <dead> flags for that.

llvm-svn: 133902

The INLINEASM MachineInstrs have an immediate operand describing each
original inline asm operand. Decode the bits in MachineInstr::print() so
it is easier to read:

  INLINEASM <es:rorq $1,$0>, $0:[regdef], %vreg0<def>, %vreg1<def>, $1:[imm], 1, $2:[reguse] [tiedto:$0], %vreg2, %vreg3, $3:[regdef-ec], %EFLAGS<earlyclobber,imp-def>

llvm-svn: 133901

llvm-svn: 133821

markers. In some cases a register def is dead on one path, but not on
another.

This is passing Clang self-hosting.

llvm-svn: 131214

It can happen that a live debug variable is the last use of a sub-register, and
the register allocator will pick a larger register class for the virtual
register.  If the allocated register doesn't support the sub-register index,
just use %noreg for the debug variables instead of asserting.

In PR9872, a debug variable ends up in the sub_8bit_hi part of a GR32_ABCD
register. The register is split and one part is inflated to GR32 and assigned
%ESI because there are no more normal uses of sub_8bit_hi.

Since %ESI doesn't have that sub-register, substPhysReg asserted. Now it will
simply insert a %noreg instead, and the debug variable will be marked
unavailable in that range.

We don't currently have a way of saying: !"value" is in bits 8-15 of %ESI, I
don't know if DWARF even supports that.

llvm-svn: 131073

llvm-svn: 130562

There can be multiple defs for a single virtual register when they are defining
sub-registers.

The missing <dead> flag was stopping the inline spiller from eliminating dead
code after rematerialization.

llvm-svn: 128888

llvm-svn: 127098

These functions not longer assert when passed 0, but simply return false instead.

No functional change intended.

llvm-svn: 123155