Vectorizer/PassManager:  I am working on moving the vectorizer out of the SCC passes. This patch moves the SLP-vectorizer and BB-vectorizer back into SCC passes for two reasons:
1. They are a kind of cannonicalization.
2. The performance measurements show that it is better to keep them in.

There should be no functional change if you are not enabling the LateVectorization mode.

llvm-svn: 189539

When unrolling is disabled in the pass manager, the loop vectorizer should also
not unroll loops. This will allow the -fno-unroll-loops option in Clang to
behave as expected (even for vectorizable loops). The loop vectorizer's
-force-vector-unroll option will (continue to) override the pass-manager
setting (including -force-vector-unroll=0 to force use of the internal
auto-selection logic).

In order to test this, I added a flag to opt (-disable-loop-unrolling) to force
disable unrolling through opt (the analog of -fno-unroll-loops in Clang). Also,
this fixes a small bug in opt where the loop vectorizer was enabled only after
the pass manager populated the queue of passes (the global_alias.ll test needed
a slight update to the RUN line as a result of this fix).

llvm-svn: 189499

Noticed by Stephen Checkoway <s@pahtak.org>.

llvm-svn: 189312

Update StripDeadDebugInfo to use DebugInfoFinder so that it is no longer stale to the point of not working and more resilient to debug info changes.

The current version of StripDeadDebugInfo became stale and no longer actually
worked since it was expecting an older version of debug info.

This patch updates it to use DebugInfoFinder and the modern DebugInfo classes as
much as possible to make it more redundent to such changes. Additionally, the
only place where that was avoided (the code where we replace the old sets with
the new), I call verify on the DIContextUnit implying that if the format changes
and my live set changes no longer make sense an assert will be hit. In order to
ensure that that occurs I have included a test case.

The actual stripping of the dead debug info follows the same strategy as was
used before in this class: find the live set and replace the old set in the
given compile unit (which may contain dead global variables/functions) with the
new live one.

llvm-svn: 189078

llvm-svn: 188957

llvm-svn: 188956

llvm-svn: 188285

I have moved this logic into clang and opt.

llvm-svn: 188281

llvm-svn: 188198

Patch by: Mei Ye

llvm-svn: 187764

llvm-svn: 187628

llvm-svn: 187595

Merge consecutive if-regions if they contain identical statements.
Both transformations reduce number of branches.  The transformation
is guarded by a target-hook, and is currently enabled only for +R600,
but the correctness has been tested on X86 target using a variety of
CPU benchmarks.

Patch by: Mei Ye

llvm-svn: 187278

The language reference says that:

"If a symbol appears in the @llvm.used list, then the compiler,
assembler, and linker are required to treat the symbol as if there is
a reference to the symbol that it cannot see"

Since even the linker cannot see the reference, we must assume that
the reference can be using the symbol table. For example, a user can add
__attribute__((used)) to a debug helper function like dump and use it from
a debugger.

llvm-svn: 187103

llvm-svn: 187099

Thanks to Nick Lewycky for noticing it.

llvm-svn: 187098

GlobalOpt simplifies llvm.compiler.used by removing any members that are also
in the more strict llvm.used. Handle the special case where llvm.compiler.used
becomes empty.

llvm-svn: 186778

We were incorrectly using compiler_used instead of compiler.used. Unfortunately
the passes using the broken name had tests also using the broken name.

llvm-svn: 186705

llvm-svn: 186622

Duncan pointed out a mistake in my fix in r186425 when only one of the allocas
being compared had the target-default alignment. This is essentially his
suggested solution. Thanks!

llvm-svn: 186510

For safety, the inliner cannot decrease the allignment on an alloca when
merging it with another.

I've included two variants of the test case for this: one with DataLayout
available, and one without. When DataLayout is not available, if only one of
the allocas uses the default alignment (getAlignment() == 0), then they cannot
be safely merged.

llvm-svn: 186425

llvm-svn: 185888

llvm-svn: 185738

functions. Make the function attributes pass add it to known library functions
and when it can deduce it.

llvm-svn: 185735

llvm-svn: 185612

Use SmallVectorImpl::iterator/const_iterator instead of SmallVector to avoid specifying the vector size.

llvm-svn: 185606

Added support in FunctionAttrs for adding relevant function/argument attributes for the posix call gettimeofday.

This implies annotating it as nounwind and its arguments as nocapture. To be
conservative, we do not annotate the arguments with noalias since some platforms
do not have restrict on the declaration for gettimeofday.

llvm-svn: 185502

llvm-svn: 185414

DeadArgumentElimination: keep return value on functions that have a live argument with the 'returned' attribute (rather than generate invalid IR); however, if both can be eliminated, both will be

llvm-svn: 185290

No functionality change.
It should suffice to check the type of a debug info metadata, instead of
calling Verify. For cases where we know the type of a DI metadata, use
assert.

Also update testing cases to make them conform to the format of DI classes.

llvm-svn: 185135

CGSCC pass manager. This should insulate the inlining decisions from the
vectorization decisions, however it may have both compile time and code
size problems so it is just an experimental option right now.

Adding this based on a discussion with Arnold and it seems at least
worth having this flag for us to both run some experiments to see if
this strategy is workable. It may solve some of the regressions seen
with the loop vectorizer.

llvm-svn: 184698

It doesn't work as I intended it to.  This reverts commit r184638.

llvm-svn: 184641

It has become an expensive operation. No functionality change.

llvm-svn: 184638

This commit completely removes what is left of the simplify-libcalls
pass.  All of the functionality has now been migrated to the instcombine
and functionattrs passes.  The following C API functions are now NOPs:

  1. LLVMAddSimplifyLibCallsPass
  2. LLVMPassManagerBuilderSetDisableSimplifyLibCalls

llvm-svn: 184459

llvm-svn: 184089

llvm-svn: 184084

llvm-svn: 184041

This pass was assuming that if hasAddressTaken() returns false for a
function, the function's only uses are call sites.  That's not true
because there can be references by BlockAddresses too.

Fix the pass to handle this case.  Fix
BlockAddress::replaceUsesOfWithOnConstant() to allow a function's type
to be changed by RAUW'ing the function with a bitcast of the recreated
function.

Patch by Mark Seaborn.

llvm-svn: 183933

Should fix the dragonegg build bots.

llvm-svn: 183845

Instead of a custom implementation of replaceAllUsesWith, we just call
replaceAllUsesWith and recreate llvm.used and llvm.compiler-used.

This change is particularity interesting because it makes llvm see
through what clang is doing with static used functions in extern "C"
contexts. With this change, running clang -O2 in

extern "C" {
  __attribute__((used)) static void foo() {}
}

produces

@llvm.used = appending global [1 x i8*] [i8* bitcast (void ()* @foo to
i8*)], section "llvm.metadata"
define internal void @foo() #0 {
entry:
  ret void
}

llvm-svn: 183756