This helps it avoid reusing an instruction that doesn't dominate all
of the users, in cases where the original instruction was inserted
before all of the users were known.  This may result in redundant
expansions of sub-expressions that depend on loop-unpredictable values
in some cases, however this isn't very common, and it primarily impacts
IndVarSimplify, so GVN can be expected to clean these up.

This eliminates the need for IndVarSimplify's FixUsesBeforeDefs,
which fixes several bugs.

llvm-svn: 74352

llvm-svn: 74351

llvm-svn: 74330

llvm-svn: 74285

Remove debug info anchors - llvm.dbg.compile_units, llvm.dbg.subprograms
and llvm.dbg.global_variables.

llvm-svn: 74251

llvm-svn: 74243

an invoke instruction, since the value isn't really live across that
edge.

llvm-svn: 74242

llvm-svn: 74240

llvm-svn: 74146

terminator, instead of after the last phi. This fixes a bug
exposed by ScalarEvolution analyzing more kinds of loops.
This fixes PR4436.

llvm-svn: 74072

trip counts in more cases.

Generalize ScalarEvolution's isLoopGuardedByCond code to recognize
And and Or conditions, splitting the code out into an
isNecessaryCond helper function so that it can evaluate Ands and Ors
recursively, and make SCEVExpander be much more aggressive about
hoisting instructions out of loops.

test/CodeGen/X86/pr3495.ll has an additional instruction now, but
it appears to be due to an arbitrary register allocation difference.

llvm-svn: 74048

preheader is already an instruction.

llvm-svn: 74031

llvm-svn: 73910

llvm-svn: 73906

now, this hasn't mattered, because ScalarEvolution hasn't been able
to compute trip counts for loops with multiple exits. But it will
soon.

llvm-svn: 73864

terminology that LoopInfo uses.

llvm-svn: 73863

llvm-svn: 73796

hand-crafted testcase which demonstrates the bug that was exposed
in 254.gap.

llvm-svn: 73793

which it isn't prepared to handle.

llvm-svn: 73787

llvm-svn: 73783

as if they were multiple uses of the same instruction.  This interacts
well with the existing loadpre that j-t does to open up many new jump
threads earlier.

llvm-svn: 73768

llvm-svn: 73755

when it allows forming a tail call.  Patch by Frits van
Bommel.  This implements PR4323.

llvm-svn: 73752

strcmp -> memcmp when the lengths of the strings are unknown.

Patch by Nick Lewycky!

llvm-svn: 73751

as signed max tests. Along with r73717, this helps CodeGen avoid
emitting code for a maximum operation for this class of loop.

llvm-svn: 73718

llvm-svn: 73715

casted induction variables in cases where the cast
isn't foldable. It ended up being a pessimization in
many cases. This could be fixed, but it would require
a bunch of complicated code in IVUsers' clients. The
advantages of this approach aren't visible enough to
justify it at this time.

llvm-svn: 73706

C is not a low-bits mask, and add a similar instcombine for
zext((trunc(t) & C) ^ C).

llvm-svn: 73705

multiple users.

llvm-svn: 73656

move loads back past a check that the load address
is valid, see new testcase.  The test that went
in with 72661 has exactly this case, except that
the conditional it's moving past is checking
something else; I've settled for changing that
test to reference a global, not a pointer.  It
may be possible to scan all the tests you pass and
make sure none of them are checking any component
of the address, but it's not trivial and I'm not
trying to do that here.

llvm-svn: 73632

llvm-svn: 73625

llvm-svn: 73621

>> What if my global variable was into a different address space than stack?
>>     
>
> It doesn't matter in terms of semantics: because AnalyzeGlobal
> returned false, we're guaranteed the address of the global is never
> taken.  I wouldn't be surprised if we end up generating invalid IR in
> some cases, though, because of the semantics of replaceAllUsesWith.
> Do you have a testcase that breaks?
>
>   
The problem is replaceAllUsesWith asserts for type mismatch here. Try attached .bc with llvm-ld.

assert(New->getType() == getType() &&
        "replaceAllUses of value with new value of different type!");

Since stack is always on address space zero, I don't think that type of GV in a different address space is ever going to match.
The other way is to allow replaceAllUsesWith to ignore address spaces while comparing types. (do we have  a way to do that ?).
But then such an optimization may fail the entire idea of user wanting to place a variable into different memory space. The original idea of user might be to save on the stack space (data memory) and hence he asked the variable to be placed into different memory space (program memory). So the best bet here is to deny this optimization by checking

GV->getType()->getAddressSpace() == 0. 

llvm-svn: 73605

SRem.

llvm-svn: 73598

llvm-svn: 73541

to ignore readonly calls, and factor it out of instcombine so
that it can be used by other passes.  Patch by Frits van Bommel!

llvm-svn: 73506

llvm-svn: 73451

failures.

To support this, add some utility functions to Type to help support
vector/scalar-independent code. Change ConstantInt::get and
ConstantFP::get to support vector types, and add an overload to
ConstantInt::get that uses a static IntegerType type, for
convenience.

Introduce a new getConstant method for ScalarEvolution, to simplify
common use cases.

llvm-svn: 73431

problem addressed in 31284, but the patch there only
addressed the case where an invoke is the first thing in
a block.

llvm-svn: 73416

llvm-svn: 73412