predecessor is itself.  This doesn't make sense, and this is
a dead infinite loop anyway.

llvm-svn: 60210

wrappers around the interesting code and use an obscure iterator
abstraction that dates back many many years.

Move EraseDeadInstructions to Transforms/Utils and name it
RecursivelyDeleteTriviallyDeadInstructions.

llvm-svn: 60191

it ends up being the entry block.

llvm-svn: 60180

llvm-svn: 60163

performance in most cases on the Grawp tester, but does speed some 
things up (like shootout/hash by 15%).  This also doesn't impact 
compile time in a noticable way on the Grawp tester.

It also, of course, gets the testcase it was designed for right :)

llvm-svn: 60120

llvm-svn: 60088

heuristic: the value is already live at the new memory operation if
it is used by some other instruction in the memop's block.  This is
cheap and simple to compute (moreso than full liveness).

This improves the new heuristic even more.  For example, it cuts two
out of three new instructions out of 255.vortex:DbmFileInGrpHdr, 
which is one of the functions that the heuristic regressed.  This
overall eliminates another 40 instructions from 403.gcc and visibly
reduces register pressure in 255.vortex (though this only actually
ends up saving the 2 instructions from the whole program).

llvm-svn: 60084

phrased in terms of liveness instead of as a horrible hack.  :)

In pratice, this doesn't change the generated code for either 
255.vortex or 403.gcc, but it could cause minor code changes in 
theory.  This is framework for coming changes.

llvm-svn: 60082

llvm-svn: 60076

-enable-smarter-addr-folding to llc) that gives CGP a better
cost model for when to sink computations into addressing modes.
The basic observation is that sinking increases register 
pressure when part of the addr computation has to be available
for other reasons, such as having a use that is a non-memory
operation.  In cases where it works, it can substantially reduce
register pressure.

This code is currently an overall win on 403.gcc and 255.vortex
(the two things I've been looking at), but there are several 
things I want to do before enabling it by default:

1. This isn't doing any caching of results, so it is much slower 
   than it could be.  It currently slows down release-asserts llc 
   by 1.7% on 176.gcc: 27.12s -> 27.60s.
2. This doesn't think about inline asm memory operands yet.
3. The cost model botches the case when the needed value is live
   across the computation for other reasons.

I'll continue poking at this, and eventually turn it on as llcbeta.

llvm-svn: 60074

optimize addressing modes.  This allows us to optimize things like isel-sink2.ll
into:

	movl	4(%esp), %eax
	cmpb	$0, 4(%eax)
	jne	LBB1_2	## F
LBB1_1:	## TB
	movl	$4, %eax
	ret
LBB1_2:	## F
	movzbl	7(%eax), %eax
	ret

instead of:

_test:
	movl	4(%esp), %eax
	cmpb	$0, 4(%eax)
	leal	4(%eax), %eax
	jne	LBB1_2	## F
LBB1_1:	## TB
	movl	$4, %eax
	ret
LBB1_2:	## F
	movzbl	3(%eax), %eax
	ret

This shrinks (e.g.) 403.gcc from 1133510 to 1128345 lines of .s.

Note that the 2008-10-16-SpillerBug.ll testcase is dubious at best, I doubt
it is really testing what it thinks it is.

llvm-svn: 60068

can recursively match things) and scales by 0 by ignoring them.
This triggers once in 403.gcc, saving 1 (!!!!) instruction in the 
whole huge app.

llvm-svn: 60013

into a new AddressingModeMatcher class.  This makes it easier
to reason about and reduces passing around of stuff, but has
no functionality change.

llvm-svn: 60012

new FindMaximalLegalAddressingModeForOperation helper method.

llvm-svn: 60011

llvm-svn: 60010

llvm-svn: 60009

llvm-svn: 59990

llvm-svn: 59989

llvm-svn: 59985

llvm-svn: 59976

with an undef.

llvm-svn: 59972

llvm-svn: 56549

llvm-svn: 56546

llvm-svn: 55779

llvm-svn: 54128

of apint codegen failure is the DAG combiner doing
the wrong thing because it was comparing MVT's using
< rather than comparing the number of bits.  Removing
the < method makes this mistake impossible to commit.
Instead, add helper methods for comparing bits and use
them.

llvm-svn: 52098

and better control the abstraction.  Rename the type
to MVT.  To update out-of-tree patches, the main
thing to do is to rename MVT::ValueType to MVT, and
rewrite expressions like MVT::getSizeInBits(VT) in
the form VT.getSizeInBits().  Use VT.getSimpleVT()
to extract a MVT::SimpleValueType for use in switch
statements (you will get an assert failure if VT is
an extended value type - these shouldn't exist after
type legalization).
This results in a small speedup of codegen and no
new testsuite failures (x86-64 linux).

llvm-svn: 52044

use it instead of duplicating its functionality.

llvm-svn: 51499

API change for {BinaryOperator|CmpInst|CastInst}::create*() --> Create. Legacy interfaces will be in place for some time.  (Merge from use-diet branch.)

llvm-svn: 51200

several things that were neither in an anonymous namespace nor static
but not intended to be global.

llvm-svn: 51017

Patch by Matthijs Kooijman!

llvm-svn: 50861

When choosing between constraints with multiple options,
like "ir", test to see if we can use the 'i' constraint and
go with that if possible.  This produces more optimal ASM in
all cases (sparing a register and an instruction to load it),
and fixes inline asm like this:

void test () {
  asm volatile (" %c0 %1 " : : "imr" (42), "imr"(14));
}

Previously we would dump "42" into a memory location (which
is ok for the 'm' constraint) which would cause a problem
because the 'c' modifier is not valid on memory operands.

Isn't it great how inline asm turns 'missed optimization'
into 'compile failed'??

Incidentally, this was the todo in 
PowerPC/2007-04-24-InlineAsm-I-Modifier.ll

Please do NOT pull this into Tak.

llvm-svn: 50315

llvm-svn: 50313

to the block that defines their operands. This doesn't work in the
case that the operand is an invoke, because invoke is a terminator
and must be the last instruction in a block.

Replace it with support in SelectionDAGISel for copying struct values
into sequences of virtual registers.

llvm-svn: 50279

llvm-svn: 49283

from their aggregate operands by moving the getresult
instructions.

llvm-svn: 48657

llvm-svn: 48556

llvm-svn: 47615

try to simplify them.

llvm-svn: 47610

operands into inline asm block.

llvm-svn: 47589