llvm-svn: 141763

1. The speculation check may not have been performed if the BB hasn't had a load
   LICM candidate.
2. If the candidate would be CSE'ed, then go ahead and speculatively LICM the
   instruction even if it's in high register pressure situation.

llvm-svn: 141747

Also teach MachineLICM to avoid "speculation" when register pressure is high.

llvm-svn: 141744

file. Since it should only be used when necessary propagate it through
the backend code generation and tweak testcases accordingly.

This helps with code like in clang's test/CodeGen/debug-info-line.c where
we have multiple #line directives within a single lexical block and want
to generate only a single block that contains each file change.

Part of rdar://10246360

llvm-svn: 141729

llvm-svn: 141728

The blocks with invokes have branches to the dispatch block, because that more
correctly models the behavior of the CFG. The dispatch of course has edges to
the landing pads. Those landing pads could contain invokes, which then have
branches back to the dispatch. This creates a loop. The machine LICM pass looks
at this loop and thinks it can hoist elements out of it. But because the
dispatch is an alternate entry point into the program, the hoisted instructions
won't be executed.

I wasn't able to get a testcase which was small and could reproduce all of the
time. The function_try_block.cpp in llvm-test was where this showed up.

llvm-svn: 141726

For example, MachineLICM should not hoist a load that is not guaranteed to be executed.
Radar 10254254.

llvm-svn: 141689

llvm-svn: 141667

Add support for legalization of vector trunc-store where the saved scalar type is illegal (for example, v2i16 on systems where the smallest store size is i32)

llvm-svn: 141661

llvm-svn: 141659

llvm-svn: 141594

Allow targets to expand COPY and other standard pseudo-instructions
before they are expanded with copyPhysReg().

This allows the target to examine the COPY instruction for extra
operands indicating it can be widened to a preferable super-register
copy.  See the ARM -widen-vmovs option.

llvm-svn: 141578

llvm-svn: 141576

For example, MachineLICM should not hoist a load that is not guaranteed to be executed.
Radar 10254254.

llvm-svn: 141569

across unwind edges. This is for the back-end which expects such things.

The code is from the original SjLj EH pass.

llvm-svn: 141463

do. This will be useful later on with the new SJLJ stuff.

llvm-svn: 141416

Fixes <rdar://problem/10235725>

llvm-svn: 141357

llvm-svn: 141356

llvm-svn: 141333

site.

llvm-svn: 141226

to the landing pad. This will be used by the back-end to generate the jump
tables for dispatching the arriving longjmp in sjlj eh.

llvm-svn: 141224

llvm-svn: 141221

PhysReg operands are not allowed to have sub-register indices at all.

For virtual registers with sub-reg indices, check that all registers in
the register class support the sub-reg index.

llvm-svn: 141220

llvm-svn: 141218

llvm-svn: 141214

EXTRACT_SUBREG is emitted as %dst = COPY %src:sub, so there is no need to
constrain the %dst register class.  RegisterCoalescer will apply the
necessary constraints if it decides to eliminate the COPY.

The %src register class does need to be constrained to something with
the right sub-registers, though.  This is currently done manually with
COPY_TO_REGCLASS nodes.  They can possibly be removed after this patch.

llvm-svn: 141207

The register class created by INSERT_SUBREG and SUBREG_TO_REG must be
legal and support the SubIdx sub-registers.

The new getSubClassWithSubReg() hook can compute that.

This may create INSERT_SUBREG instructions defining a larger register
class than the sub-register being inserted.  That is OK,
RegisterCoalescer will constrain the register class as needed when it
eliminates the INSERT_SUBREG instructions.

llvm-svn: 141198

TwoAddressInstructionPass should annotate instructions with <undef>
flags when it lower REG_SEQUENCE instructions.  LiveIntervals should not
be in the business of modifying code (except for kill flags, perhaps).

llvm-svn: 141187

For example:

  %vreg10:dsub_0<def,undef> = COPY %vreg1
  %vreg10:dsub_1<def> = COPY %vreg2

is rewritten as:

  %D2<def> = COPY %D0, %Q1<imp-def>
  %D3<def> = COPY %D1, %Q1<imp-use,kill>, %Q1<imp-def>

The first COPY doesn't care about the previous value of %Q1, so it
doesn't read that register.

The second COPY is a partial redefinition of %Q1, so it implicitly kills
and redefines that register.

This makes it possible to recognize instructions that can harmlessly
clobber the full super-register.  The write and don't read the
super-register.

llvm-svn: 141139

RegisterCoalescer can create sub-register defs when it is joining a
register with a sub-register.  Add <undef> flags to these new
sub-register defs where appropriate.

llvm-svn: 141138

Teach the MC to output code/data region marker labels in MachO and ELF modes.  These are used by disassemblers to provide better disassembly, particularly on targets like ARM Thumb that like to intermingle data in the TEXT segment.

llvm-svn: 141135

llvm-svn: 141125

The <undef> flag says that a MachineOperand doesn't read its register,
or doesn't depend on the previous value of its register.

A full register def never depends on the previous register value.  A
partial register def may depend on the previous value if it is intended
to update part of a register.

For example:

  %vreg10:dsub_0<def,undef> = COPY %vreg1
  %vreg10:dsub_1<def> = COPY %vreg2

The first copy instruction defines the full %vreg10 register with the
bits not covered by dsub_0 defined as <undef>.  It is not considered a
read of %vreg10.

The second copy modifies part of %vreg10 while preserving the rest.  It
has an implicit read of %vreg10.

This patch adds a MachineOperand::readsReg() method to determine if an
operand reads its register.

Previously, this was modelled by adding a full-register <imp-def>
operand to the instruction.  This approach makes it possible to
determine directly from a MachineOperand if it reads its register.  No
scanning of MI operands is required.

llvm-svn: 141124

llvm-svn: 141050

llvm-svn: 141040

Move the grabbing of the jump buffer into the caller function, eliminating the need for returning a std::pair.

llvm-svn: 141026

llvm-svn: 141005

llvm-svn: 141004

Moved type construction out of the loop and added an assert on the legality of the type. Formatted lines to the 80 char limit.

llvm-svn: 140952

and the alignment is 0 (i.e., it's defined globally in one file and declared in
another file) it could get an alignment which is larger than the ABI allows for
that type, resulting in aligned moves being used for unaligned loads.

For instance, in file A.c:

   struct S s;

In file B.c:
   struct {
     // something long
   };
   extern S s;

   void foo() {
     struct S p = s;
     // ...
   }

this copy is a 'memcpy' which is turned into a series of 'movaps' instructions
on X86. But this is wrong, because 'struct S' has alignment of 4, not 16.

llvm-svn: 140902