important because it is sinking the loads using the GEPs, but
not the GEPs themselves.  This triggers 647 times on 403.gcc
and makes the .s file much much nicer.  For example before:

        je      LBB1_87 ## bb78
LBB1_62:        ## bb77
        leal    84(%esi), %eax
LBB1_63:        ## bb79
        movl    (%eax), %eax
...
LBB1_87:        ## bb78
        movl    $0, 4(%esp)
        movl    %esi, (%esp)
        call    L_make_decl_rtl$stub
        jmp     LBB1_62 ## bb77


after:

        jne     LBB1_63 ## bb79
LBB1_62:        ## bb78
        movl    $0, 4(%esp)
        movl    %esi, (%esp)
        call    L_make_decl_rtl$stub
LBB1_63:        ## bb79
        movl    84(%esi), %eax

The input code was (and the GEPs are merged and
the PHI is now eliminated by instcombine):

        br i1 %tmp233, label %bb78, label %bb77
bb77:           
        %tmp234 = getelementptr %struct.tree_node* %t_addr.3, i32 0, i32 0, i32 22              
        br label %bb79
bb78:           
        call void @make_decl_rtl(%struct.tree_node* %t_addr.3, i8* null) nounwind
        %tmp235 = getelementptr %struct.tree_node* %t_addr.3, i32 0, i32 0, i32 22              
        br label %bb79
bb79:           
        %iftmp.12.0.in = phi %struct.rtx_def** [ %tmp235, %bb78 ], [ %tmp234, %bb77 ]           
        %iftmp.12.0 = load %struct.rtx_def** %iftmp.12.0.in             

llvm-svn: 60322

llvm-svn: 60321

llvm-svn: 60320

Add Sema::isNullPointerConstant which extwarns if necessary. Use it in Sema::CheckConditionalOperands.

llvm-svn: 60319

llvm-svn: 60318

llvm-svn: 60317

llvm-svn: 60316

llvm-svn: 60315

elimination: when finding dependent load/stores, realize that
they are the same if aliasing claims must alias instead of relying
on the pointers to be exactly equal.  This makes load elimination
more aggressive.  For example, on 403.gcc, we had:

<     68 gvn    - Number of instructions PRE'd
< 152718 gvn    - Number of instructions deleted
<  49699 gvn    - Number of loads deleted
<   6153 memdep - Number of dirty cached non-local responses
< 169336 memdep - Number of fully cached non-local responses
< 162428 memdep - Number of uncached non-local responses

now we have:

>     64 gvn    - Number of instructions PRE'd
> 153623 gvn    - Number of instructions deleted
>  49856 gvn    - Number of loads deleted
>   5022 memdep - Number of dirty cached non-local responses
> 159030 memdep - Number of fully cached non-local responses
> 162443 memdep - Number of uncached non-local responses

That's an extra 157 loads deleted and extra 905 other instructions nuked.

This slows down GVN very slightly, from 3.91 to 3.96s.

llvm-svn: 60314

vector instead of a densemap.  This shrinks the memory usage of this thing
substantially (the high water mark) as well as making operations like
scanning it faster.  This speeds up memdep slightly, gvn goes from
3.9376 to 3.9118s on 403.gcc

This also splits out the statistics for the cached non-local case to
differentiate between the dirty and clean cached case.  Here's the stats
for 403.gcc:

  6153 memdep - Number of dirty cached non-local responses
169336 memdep - Number of fully cached non-local responses
162428 memdep - Number of uncached non-local responses

yay for caching :)

llvm-svn: 60313

permutations of this pattern.

llvm-svn: 60312

an 128-bit-wide integer.  No testcase; the issue I ran into depends on 
local changes.

llvm-svn: 60311

This speeds up GVN from 4.0386s to 3.9376s.

llvm-svn: 60310

remove some fixme's.  This speeds up GVN very slightly on 403.gcc 
(4.06->4.03s)

llvm-svn: 60309

redundant with MemDepResult, and MemDepResult has a nicer interface.

llvm-svn: 60308

functional change.

llvm-svn: 60307

Note that the FoldOpIntoPhi call is dead because it's impossible for the 
first operand of a subtraction to be both a ConstantInt and a PHINode.

llvm-svn: 60306

llvm-svn: 60305

getAnalysis<>.  getAnalysis<> is apparently extremely expensive.
Doing this speeds up GVN on 403.gcc by 16%!

llvm-svn: 60304

llvm-svn: 60303

llvm-svn: 60301

llvm-svn: 60300

llvm-svn: 60299

llvm-svn: 60298

llvm-svn: 60297

llvm-svn: 60296

llvm-svn: 60295

llvm-svn: 60291

takes care of all permutations of this pattern.

llvm-svn: 60290

llvm-svn: 60289

APInt calls instead.

This fixes PR3144.

llvm-svn: 60288

only show up in code from front-ends besides llvm-gcc, like clang.

llvm-svn: 60287

llvm-svn: 60286

Hopefully this isn't too much stuff to dump into this file.

llvm-svn: 60285

as unsigned divisions.  Same caveats as before.

llvm-svn: 60284

multiplies.

Some more cleverness would be nice, though. It would be nice if we 
could do this transformation on illegal types.  Also, we would 
prefer a narrower constant when possible so that we can use a narrower
multiply, which can be cheaper.

llvm-svn: 60283

llvm-svn: 60282

llvm-svn: 60281

This fixes PR3127
http://llvm.org/bugs/show_bug.cgi?id=3127

llvm-svn: 60280

llvm-svn: 60279