use a SUB instruction instead of an ADD, because -128 can be
encoded in an 8-bit signed immediate field, while +128 can't be.
This avoids the need for a 32-bit immediate field in this case.

A similar optimization applies to 64-bit adds with 0x80000000,
with the 32-bit signed immediate field.

To support this, teach tablegen how to handle 64-bit constants.

llvm-svn: 57663

shift counts, and patterns that match dynamic shift counts
when the subtract is obscured by a truncate node.

Add DAGCombiner support for recognizing rotate patterns
when the shift counts are defined by truncate nodes.

Fix and simplify the code for commuting shld and shrd
instructions to work even when the given instruction doesn't
have a parent, and when the caller needs a new instruction.

These changes allow LLVM to use the shld, shrd, rol, and ror
instructions on x86 to replace equivalent code using two
shifts and an or in many more cases.

llvm-svn: 57662

llvm-svn: 57649

llvm-svn: 57644

uninitialized in these functions with gcc-4.3.

llvm-svn: 57635

llvm-svn: 57631

x86 backend.  These will all be answered with "patches welcome", so
a PR doesn't help drive them along.

llvm-svn: 57630

basically working, feel free to remove the tag.  The other targets have
really basic things that break them.

llvm-svn: 57628

llvm-svn: 57622

llvm-svn: 57621

an unindexed load.

llvm-svn: 57612

llvm-svn: 57586

llvm-svn: 57582

llvm-svn: 57579

the predicates by extending simple predicates to create
more complex predicates instead of duplicating the logic
for the simple predicates.

This doesn't reduce much redundancy in DAGISelEmitter.cpp's
generated source yet; that will require improvements to
DAGISelEmitter.cpp's instruction sorting, to make it more
effectively group nodes with similar predicates together.

llvm-svn: 57565

llvm-svn: 57557

are due to argument passing in calls.  This is significant because
it hits all immediate arguments to calls on x86-32.

llvm-svn: 57556

this:

-	movl	$0, %eax
-	movl	%eax, _yy_n_chars
+	movl	$0, _yy_n_chars

llvm-svn: 57555

llvm-svn: 57553

1. Compute action in X86SelectSelect based on MVT instead of type.
2. Use TLI.getValueType(..) instead of MVT::getVT(..) because the former
   handles pointers and the later doesn't.
3. Don't pass TLI into isTypeLegal, since it already has access to it as 
   an ivar.

#2 gives fast isel some minor new functionality: handling load/stores of
pointers.

llvm-svn: 57552

llvm-svn: 57551

change the generated code, but makes the code simpler.

llvm-svn: 57550

which makes it easy to share the compare/imm folding logic with 'setcc'.
This shaves a bunch of instructions off the common select case, which
happens a lot in llvm-gcc.

llvm-svn: 57549

loading 4 into a register and then doing the compare.

llvm-svn: 57548

llvm-svn: 57547

llvm-svn: 57546

llvm-svn: 57545

llvm-svn: 57544

i.e. conditions that cannot be checked with a single instruction. For example,
SETONE and SETUEQ on x86.
- Teach legalizer to implement *illegal* setcc as a and / or of a number of
legal setcc nodes. For now, only implement FP conditions. e.g. SETONE is
implemented as SETO & SETNE, SETUEQ is SETUO | SETEQ.
- Move x86 target over.

llvm-svn: 57542

 - Move the EH landing-pad code and adjust it so that it works
   with FastISel as well as with SDISel.
 - Add FastISel support for @llvm.eh.exception and
   @llvm.eh.selector.

llvm-svn: 57539

for pentium).  Fixes
gcc.target/i386/20000720-1.c
gcc.target/i386/pr26826.c

llvm-svn: 57528

llvm-svn: 57526

llvm-svn: 57524

instead of requiring all "short description" strings to begin with
two spaces. This makes these strings less mysterious, and it fixes
some cases where short description strings mistakenly did not
begin with two spaces.

llvm-svn: 57521

llvm-svn: 57508

create a new DAG node to represent the new shift to keep the
DAG consistent, even though it'll almost always be folded into
the address.

If a user of the resulting address has multiple uses, the
nodes may get revisited by a later MatchAddress call, in which
case DAG inconsistencies do matter.

This fixes PR2849.

llvm-svn: 57465

llvm-svn: 57414

parameters instead of raw Constants.  This prevents the constants from
being selected by the isel pass, fixing PR2735.

llvm-svn: 57385

llvm-svn: 57381

llvm-svn: 57380