In functions where we fully constant prop the return value, replace all
ret instructions with 'ret undef'.

llvm-svn: 18786

llvm-svn: 18781

llvm-svn: 18776

This implements SCCP/ipsccp-basic.ll, rips apart Olden/mst (as described in
PR415), and does other nice things.

There is still more to come with this, but it's a start.

llvm-svn: 18752

llvm-svn: 17897

llvm-svn: 17825

llvm-svn: 17824

 1. Speedup getValueState by having it not consider Arguments.  It's better
    to just add them before we start SCCP'ing.
 2. SCCP can delete the contents of dead blocks.  No really, it's ok!  This
    reduces the size of the IR for subsequent passes, even though
    simplifycfg would do the same job.  In practice, simplifycfg does not
    run until much later than sccp in gccas

llvm-svn: 17820

llvm-svn: 17818

class.  The only changes are minor:

 * Do not try to SCCP instructions that return void in the rewrite loop.
   This is silly and fool hardy, wasting a map lookup and adding an entry
   to the map which is never used.
 * If we decide something has an undefined value, rewrite it to undef,
   potentially leading to further simplications.

llvm-svn: 17816

and work better with VC++.  Patch contributed by Morten Ofstad!

llvm-svn: 17281

ignore unreachable instructions

llvm-svn: 17044

-debug-only!

llvm-svn: 16868

llvm-svn: 16432

Patch contributed by Paolo Invernizzi. Thanks Paolo!

llvm-svn: 16368

Move include/Config and include/Support into include/llvm/Config,
include/llvm/ADT and include/llvm/Support. From here on out, all LLVM
public header files must be under include/llvm/.

llvm-svn: 16137

llvm-svn: 15487

llvm-svn: 14967

- Replace ConstantPointerRef usage with GlobalValue usage
- Correct isa<Constant> for GlobalValue subclass

llvm-svn: 14947

Speed up SCCP substantially by processing overdefined values quickly.  This
patch speeds up SCCP by about 30-40% on large testcases.

llvm-svn: 14861

llvm-svn: 14839

test/Regression/Transforms/SCCP/calltest.ll

llvm-svn: 12921

types and can have arbitrary 32- and 64-bit integer types indexing into
sequential types.

llvm-svn: 12653

time from 615s to 1.49s on a large testcase that has a gigantic switch statement
that all of the blocks in the function go to (an intepreter).

llvm-svn: 12442

llvm-svn: 12318

a zero value is the most likely way to cause further simplification, so we do it.

llvm-svn: 12197

llvm-svn: 11474

llvm-svn: 10791

llvm-svn: 10779

constants as being "true" when evaluating branches.  This was introduced
because we now create constantexprs for the constants instead of failing the
fold.

llvm-svn: 10778

* Implement SCCP of load instructions, implementing Transforms/SCCP/loadtest.ll
  This allows us to fold expressions like "foo"[2], even if the pointer is only
  a conditional constant.

llvm-svn: 10767

llvm-svn: 10763

llvm-svn: 10725

llvm-svn: 9903

Header files will be on the way.

llvm-svn: 9298

llvm-svn: 9225

llvm-svn: 9027

llvm-svn: 8965

to avoid reprocessing PHI nodes needlessly.  This speeds up the big bad PHI
testcase 43%: from 104.9826 to 73.5157s

llvm-svn: 8964

llvm-svn: 8963