Prolangs-C/agrep and SCCP/2006-10-23-IPSCCP-Crash.ll

llvm-svn: 31132

1. Better document what is going on here.
2. Only hack on one branch per iteration, making the results less conservative.
3. Handle the problematic case by marking edges executable instead of by
   playing with value lattice states.  This is far less pessimistic, and fixes
   SCCP/ipsccp-gvar.ll.

llvm-svn: 31106

llvm-svn: 31073

Eliminate ConstantBool::True and ConstantBool::False.  Instead, provide
ConstantBool::getTrue() and ConstantBool::getFalse().

llvm-svn: 30665

llvm-svn: 29925

llvm-svn: 27513

test/Regression/Transforms/SCCP/select.ll

llvm-svn: 26049

llvm-svn: 25514

llvm-svn: 25406

llvm-svn: 25180

ConstantFoldLoadThroughGEPConstantExpr function in the utils lib.

llvm-svn: 23446

llvm-svn: 21480

llvm-svn: 21427

Make IPSCCP strip off dead constant exprs that are using functions, making
them appear as though their address is taken.  This allows us to propagate
some more pool descriptors, lowering the overhead of pool alloc.

llvm-svn: 21363

using Function::arg_{iterator|begin|end}.  Likewise Module::g* -> Module::global_*.

This patch is contributed by Gabor Greif, thanks!

llvm-svn: 20597

llvm-svn: 19379

if the other side is overdefined.

This allows us to fold conditions like:  if (X < Y || Y > Z) in some cases.

llvm-svn: 18807

 1. Actually increment the Statistic for the GV elim optzn
 2. When resolving undef branches, only resolve branches in executable blocks,
    avoiding marking a bunch of completely dead blocks live.  This has a big
    impact on the quality of the generated code.

With this patch, we positively rip up vortex, compiling Ut_MoveBytes to a
single memcpy call. In vortex we get this:

     12 ipsccp           - Number of globals found to be constant
    986 ipsccp           - Number of arguments constant propagated
   1378 ipsccp           - Number of basic blocks unreachable
   8919 ipsccp           - Number of instructions removed

llvm-svn: 18796

llvm-svn: 18795

non-address-taken global variables.

llvm-svn: 18790

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