reduce down to a single value.  InstCombine already does this transformation
but DAG legalization may introduce new opportunities.  This has turned out to
be important for ARM where 64-bit values are split up during type legalization:
InstCombine is not able to remove the PHI cycles on the 64-bit values but
the separate 32-bit values can be optimized.  I measured the compile time 
impact of this (running llc on 176.gcc) and it was not significant.

llvm-svn: 95951

only run for x86 with fastisel. I've found it being very effective in
eliminating some obvious dead code as result of formal parameter lowering
especially when tail call optimization eliminated the need for some of the loads
from fixed frame objects. It also shrinks a number of the tests. A couple of
tests no longer make sense and are now eliminated.

llvm-svn: 95493

add -filetype=null for performance testing and remove -filetype=dynlib,
which isn't planned to be implemented.

llvm-svn: 95202

llvm-svn: 95168

stderr if in filetype=obj mode.  This is a hack, and will
live until dwarf emission and other random stuff that is
not yet going through MCStreamer is upgraded.  It only
impacts filetype=obj mode.

llvm-svn: 95166

$ cat t.ll 
@g = global i32 42
$ llc t.ll -o t.o -filetype=obj
$ nm t.o
00000000 D _g

There is still a ton of work left.  Instructions are not being encoded
yet apparently.

llvm-svn: 95162

llvm-svn: 95156

mccontext instead of having AsmPrinter do it.  This allows other 
types of MCStreamer's to be passed in.

llvm-svn: 95155

llvm-svn: 95153

move handling of asm-verbose out of AsmPrinter.cpp into LLVMTargetMachine.cpp with the rest of the command line options.

llvm-svn: 95152

Now the only use of the ELF writer is the JIT, which won't be
easy to fix in the short term. :( :(

llvm-svn: 95148

of the code generator shouldn't care what object format a target
uses.

llvm-svn: 95124

the one used by the JIT.  Remove all forms of
addPassesToEmitFileFinish except the one used by the static
code generator.  Inline the remaining version of
addPassesToEmitFileFinish into its only caller.

llvm-svn: 95109

the -print-emitted-asm option.  The JIT shouldn't have to pull
in the asmprinter.

llvm-svn: 95100

The MCStreamer based assemblers will take over for this functionality.

llvm-svn: 95033

LoopStrengthReduce, as it's causing too much trouble (even with the
old LoopStrengthReduce code).

llvm-svn: 94172

they reach codegen.

llvm-svn: 94066

the -pre-regalloc-taildup command-line option, and add a new
-disable-early-taildup option.

llvm-svn: 93597

Remove most of old Mach-O Writer support, it has been replaced by MCMachOStreamer

Further refactoring to completely remove MachOWriter and drive the object file
writer with the AsmPrinter MCInst/MCSection logic is forthcoming.

llvm-svn: 93527

llvm-svn: 93459

catch info can get misplaced when a selector ends up more than one block
removed from the parent invoke(s). This could happen when a landing pad is
shared by multiple invokes and is also a target of a normal edge from
elsewhere.

llvm-svn: 93456

llvm-svn: 93313

llvm-svn: 93286

llvm-svn: 93285

Add a quick pass to optimize sign / zero extension instructions. For targets where the pre-extension values are available in the subreg of the result of the extension, replace the uses of the pre-extension value with the result + extract_subreg.

For now, this pass is fairly conservative. It only perform the replacement when both the pre- and post- extension values are used in the block. It will miss cases where the post-extension values are live, but not used.

llvm-svn: 93278

llvm-svn: 92874

Change errs() to dbgs().

llvm-svn: 92524

by allowing backends to override routines that will default
the JIT and Static code generation to an appropriate code model
for the architecture.

Should fix PR 5773.

llvm-svn: 91824

llvm-svn: 91604

Revert 91280-91283, 91286-91289, 91291, 91293, 91295-91296. It apparently introduced a non-deterministic behavior in the optimizer somewhere.

llvm-svn: 91598

llvm-svn: 90567

llvm-svn: 89968

running tail duplication when doing branch folding for if-conversion, and
we also want to be able to run tail duplication earlier to fix some
reg alloc problems.  Move the CanFallThrough function from BranchFolding
to MachineBasicBlock so that it can be shared by TailDuplication.

llvm-svn: 89904

llvm-svn: 89790

just before codegen.

llvm-svn: 89439

llvm-svn: 86092

llvm-svn: 86044

previously running CodePlacementOpt. Also print headers before
each dump in -print-machineinstrs mode, so that it's clear which
dump is which.

llvm-svn: 85681

to unfold loop-invariant loads.

llvm-svn: 85657

llvm-svn: 85460