llvm-svn: 61349

truely deleted. These will be expanded with further checks of all of the data
structures.

llvm-svn: 61347

llvm-svn: 61297

our optz'n will apply to it, then build the replacement vector only if needed.

llvm-svn: 61279

- CodeGenPrepare does not split loop back edges but it only knows about back edges of single block loops. It now does a DFS walk to find loop back edges.
- Use SplitBlockPredecessors to factor out common predecessors of the critical edge destination. This is disabled for now due to some regressions.

llvm-svn: 61248

llvm-svn: 61222

llvm-svn: 61219

Simplifying the sdiv might allow further simplifications for our users.

llvm-svn: 61196

llvm-svn: 61195

bit from the original function to the cloned one.

llvm-svn: 61194

llvm-svn: 61181

my last patch to this file.

The issue there was that all uses of an IV inside a loop
are actually references to Base[IV*2], and there was one
use outside that was the same but LSR didn't see the base
or the scaling because it didn't recurse into uses outside
the loop; thus, it used base+IV*scale mode inside the loop
instead of pulling base out of the loop.  This was extra bad
because register pressure later forced both base and IV into
memory.  Doing that recursion, at least enough
to figure out addressing modes, is a good idea in general;
the change in AddUsersIfInteresting does this.  However,
there were side effects....

It is also possible for recursing outside the loop to
introduce another IV where there was only 1 before (if
the refs inside are not scaled and the ref outside is).
I don't think this is a common case, but it's in the testsuite.
It is right to be very aggressive about getting rid of
such introduced IVs (CheckForIVReuse and the handling of
nonzero RewriteFactor in StrengthReduceStridedIVUsers).
In the testcase in question the new IV produced this way
has both a nonconstant stride and a nonzero base, neither
of which was handled before.  (This patch does not handle 
all the cases where this can happen.)  And when inserting 
new code that feeds into a PHI, it's right to put such 
code at the original location rather than in the PHI's 
immediate predecessor(s) when the original location is outside 
the loop (a case that couldn't happen before)
(RewriteInstructionToUseNewBase); better to avoid making
multiple copies of it in this case.

Everything above is exercised in
CodeGen/X86/lsr-negative-stride.ll (and ifcvt4 in ARM which is
the same IR).

llvm-svn: 61178

and safe and orthogonal from turning off load pre.

llvm-svn: 61177

llvm-svn: 61175

with everyone's favorite error messages:

Comparing stages 2 and 3
warning: ./cc1-checksum.o differs
warning: ./cc1plus-checksum.o differs
Bootstrap comparison failure!
./c-decl.o differs
./cp/decl.o differs
./df-core.o differs
./gcc.o differs
./i386.o differs
./stor-layout.o differs
./tree-pretty-print.o differs
./tree.o differs
make[2]: *** [compare] Error 1
make[1]: *** [stage3-bubble] Error 2

See PR3227.

llvm-svn: 61169

iterator invalidation problems.

llvm-svn: 61124

nodes.  This allows it to do fairly general phi insertion if a 
load from a pointer global wants to be SRAd but the load is used
by (recursive) phi nodes.  This fixes a pessimization on ppc
introduced by Load PRE.

llvm-svn: 61123

can be negative.  Keep track of whether all uses of
an IV are outside the loop.  Some cosmetics; no
functional change.

llvm-svn: 61109

the load multiple times, make sure the check the uses of the PHI to 
ensure they are transformable.

llvm-svn: 61102

llvm-svn: 61101

consistently for deleting branches.  In addition to being slightly 
more readable, this makes SimplifyCFG a bit better 
about cleaning up after itself when it makes conditions unused.

llvm-svn: 61100

llvm-svn: 61081

variable sized array allocations.

llvm-svn: 61051

llvm-svn: 61047

llvm-svn: 61046

Use GetElementPtrInst::hasAllZeroIndices where possible.

llvm-svn: 61045

CFG when there is exactly one predecessor where the load is not available.
This is designed to not increase code size but still eliminate partially
redundant loads.  This fires 1765 times on 403.gcc even though it doesn't
do critical edge splitting yet (the most common reason for it to fail).

llvm-svn: 61027

llvm-svn: 61024

cleans up the generated code a bit.  This should have the added benefit of
not randomly renaming functions/globals like my previous patch did. :)

llvm-svn: 61023

Add support for slow-path GVN with full phi construction for scalars.  This is disabled for now, as it actually pessimizes code in the abscence
of phi translation for load elimination.  This slow down GVN a bit, by about 2% on 403.gcc.

llvm-svn: 61021

llvm-svn: 61012

llvm-svn: 61009

llvm[2]: Linking Release executable opt (without symbols)
...
Undefined symbols:
  "llvm::APFloat::IEEEsingle", referenced from:
      __ZN4llvm7APFloat10IEEEsingleE$non_lazy_ptr in libLLVMCore.a(Constants.o)
      __ZN4llvm7APFloat10IEEEsingleE$non_lazy_ptr in libLLVMCore.a(AsmWriter.o)
      __ZN4llvm7APFloat10IEEEsingleE$non_lazy_ptr in libLLVMCore.a(ConstantFold.o)
  "llvm::APFloat::IEEEdouble", referenced from:
      __ZN4llvm7APFloat10IEEEdoubleE$non_lazy_ptr in libLLVMCore.a(Constants.o)
      __ZN4llvm7APFloat10IEEEdoubleE$non_lazy_ptr in libLLVMCore.a(AsmWriter.o)
      __ZN4llvm7APFloat10IEEEdoubleE$non_lazy_ptr in libLLVMCore.a(ConstantFold.o)
ld: symbol(s) not found

This is in release mode. To replicate, compile llvm and llvm-gcc in optimized
mode. Then build llvm, in optimized mode, with the newly created compiler.

llvm-svn: 60977

a pretification of the IR.

llvm-svn: 60973

llvm-svn: 60971

of a pointer.  This allows is to catch more equivalencies.  For example,
the type_lists_compatible_p function used to require two iterations of
the gvn pass (!) to delete its 18 redundant loads because the first pass
would CSE all the addressing computation cruft, which would unblock the
second memdep/gvn passes from recognizing them.  This change allows
memdep/gvn to catch all 18 when run just once on the function (as is 
typical :) instead of just 3.

On all of 403.gcc, this bumps up the # reundandancies found from:

     63 gvn    - Number of instructions PRE'd
 153991 gvn    - Number of instructions deleted
  50069 gvn    - Number of loads deleted
to:
     63 gvn    - Number of instructions PRE'd
 154137 gvn    - Number of instructions deleted
  50185 gvn    - Number of loads deleted

+120 loads deleted isn't bad.

llvm-svn: 60799

pointer stuff from it, simplifying the code a bit.

llvm-svn: 60783

MemDep::getNonLocalPointerDependency method.  There are
some open issues with this (missed optimizations) and
plenty of future work, but this does allow GVN to eliminate
*slightly* more loads (49246 vs 49033).

Switching over now allows simplification of the other code
path in memdep.

llvm-svn: 60780

llvm-svn: 60779

on test/CodeGen/Generic/2007-06-06-CriticalEdgeLandingPad.

llvm-svn: 60739