1. Fix a REALLY nasty cyclic replacement issue that Anshu discovered, causing
   nondeterminstic crashes and memory corruption.
2. For performance, don't go inserting constantexpr casts of GV pointers.

This should definitely go into 1.3

llvm-svn: 15568

should go into 1.3

llvm-svn: 15567

llvm-svn: 15487

llvm-svn: 15410

llvm-svn: 15369

llvm-svn: 15343

llvm-svn: 15342

llvm-svn: 15337

llvm-svn: 15334

llvm-svn: 15328

llvm-svn: 15325

This change fixed a bug in the function visitMul.  The prior version
assumed that a constant on the RHS of a multiplication was either an
IntConstant or an FPConstant.  It checked for an IntConstant and then,
if it did not find one, did a hard cast to an FPConstant.  That code
would crash if the RHS were a ConstantExpr that was neither an
IntConstant nor an FPConstant.  This version replaces the hard cast
with a dyn_cast.  It performs the same way for IntConstants and
FPConstants but does nothing, instead of crashing, for constant
expressions.

The regression test for this change is 2004-07-27-ConstantExprMul.ll.

llvm-svn: 15291

llvm-svn: 15276

llvm-svn: 15263

end of the function (either return or unwind)

llvm-svn: 15232

llvm-svn: 15227

  a bug in DSE).
* Delete dead operand uses iteratively instead of recursively, using a
  SetVector.
* Defer deletion of dead operand uses until the end of processing, which means
  we don't have to bother with updating the AliasSetTracker.  This speeds up
  DSE substantially.

llvm-svn: 15204

llvm-svn: 15199

llvm-svn: 15162

can be improved in many ways.  But: stop laughing, even with -basicaa it
deletes 15% of the stores in 252.eon :)

llvm-svn: 15101

to the field being updated.  Patch contributed by Tobias Nurmiranta

llvm-svn: 15097

llvm-svn: 15089

* Test for whether bits are shifted out during the optzn.

If so, the fold is illegal, though it can be handled explicitly for setne/seteq

This fixes the miscompilation of 254.gap last night, which was a latent bug
exposed by other optimizer improvements.

llvm-svn: 15085

"simplify" a bit of code for comparison/and folding

llvm-svn: 15082

the appopriate size.  This gives us the ability to eliminate int -> ptr -> int

llvm-svn: 15063

return, clone the 'ret' BB code into the block AFTER the inlined call, not the
other way around.

llvm-svn: 15030

llvm-svn: 15029

to constify 14 globals instead of 4 in a trivial C++ testcase.

llvm-svn: 15027

llvm-svn: 15024

llvm-svn: 15022

actually care about.  Someday when the cast instruction is gone, we can do
better here, but this will do for now.  This implements
instcombine/cast.ll:test17/18 as well.

llvm-svn: 15018

llvm-svn: 14974

night compiling cfrac.  It did not realize that code like this:

int G; int *H = &G;

takes the address of G.

llvm-svn: 14973

llvm-svn: 14972

llvm-svn: 14968

llvm-svn: 14967

llvm-svn: 14966

llvm-svn: 14965

too.

llvm-svn: 14964

llvm-svn: 14963