it is only a partial fix.  This change is noise for most programs, but
speeds up Shootout-C++/matrix by 20%, Ptrdist/ks by 24%, smg2000 by 8%,
hexxagon by 9%, bzip2 by 9% (not sure I trust this), ackerman by 13%, etc.

OTOH, it slows down Shootout/fib2 by 40% (I'll update PR1877 with this info).

llvm-svn: 45354

    define void @f() {
            ...
            call i32 @g()
            ...
    }

    define void @g() {
            ...
    }

The hazards are:

  - @f and @g have GC, but they differ GC. Inlining is invalid. This
    may never occur.
  - @f has no GC, but @g does. g's GC must be propagated to @f.

The other scenarios are safe:

  - @f and @g have the same GC.
  - @f and @g have no GC.
  - @g has no GC.

This patch adds inliner checks for the former two scenarios.

llvm-svn: 45351

When specified, don't split backedges of single-bb loops.
This helps address PR1877

llvm-svn: 45344

us to compile:
#include <math.h>
int t1(double d) { return signbit(d); }

into:

_t1:
	movd	%xmm0, %rax
	shrq	$63, %rax
	ret

instead of:

_t1:
	movd	%xmm0, %rax
	shrq	$32, %rax
	shrl	$31, %eax
	ret

on x86-64.

llvm-svn: 45311

not merge current bb and succ even if bb's terminator is
unconditional branch to succ.

llvm-svn: 45305

return attributes on the floor.  In the case of a call
to a varargs function where the varargs arguments are
being removed, any call attributes on those arguments
need to be dropped.  I didn't do this because I plan to
make it illegal to have such attributes (see next patch).
With this change, compiling the gcc filter2 eh test at -O0
and then running opt -std-compile-opts on it results in
a correctly working program (compiling at -O1 or higher
results in the test failing due to a problem with how we
output eh info into the IR).

llvm-svn: 45285

(icmp slt (sub A B) 1) -> (icmp sle A B)
icmp sgt (sub A B) -1) -> (icmp sge A B)

and add testcase.

llvm-svn: 45256

Clean up previous patch: PHI uses should not prevent iv reuse if all other uses are addresses. This trades a constant multiply for one fewer iv.

llvm-svn: 45251

has a single use, and generalize it to not require N to be a constant.

llvm-svn: 45250

llvm-svn: 45230

calls 'nounwind'.  It is important for correct C++
exception handling that nounwind markings do not get
lost, so this transformation is actually needed for
correctness.

llvm-svn: 45218

from
_foo:
        movl    $99, %ecx
        movl    4(%esp), %eax
        subl    %eax, %ecx
        xorl    %edx, %edx
        testl   %ecx, %ecx
        cmovs   %edx, %eax
        ret

to
_foo:
        xorl    %ecx, %ecx
        movl    4(%esp), %eax
        cmpl    $99, %eax
        cmovg   %ecx, %eax
        ret

llvm-svn: 45173

llvm-svn: 45170

llvm-svn: 45169

doesNotThrow.

llvm-svn: 45160

llvm-svn: 45159

Fold certain additions through selects (and their compares) so as to eliminate subtractions. This code is often produced by the SMAX expansion in SCEV.

This implements test/Transforms/InstCombine/2007-12-18-AddSelCmpSub.ll

llvm-svn: 45158

how to lower them (with no attempt made to be
efficient, since they should only occur for
unoptimized code).

llvm-svn: 45108

GLIBCXX_DEBUG fix.  std::vector<>::end() is invalidated by erase.

llvm-svn: 45101

Get rid of annoying spaces.

llvm-svn: 45100

passed the erased element.

llvm-svn: 45099

Change the PointerType api for creating pointer types. The old functionality of PointerType::get() has become PointerType::getUnqual(), which returns a pointer in the generic address space. The new prototype of PointerType::get() requires both a type and an address space.

llvm-svn: 45082

changed not to reject invoke of inline asm.

llvm-svn: 45077

calls.  Remove special casing of inline asm from the
inliner.  There is a potential problem: the verifier
rejects invokes of inline asm (not sure why).  If an
asm call is not marked "nounwind" in some .ll, and
instcombine is not run, but the inliner is run, then
an illegal module will be created.  This is bad but
I'm not sure what the best approach is.  I'm tempted
to remove the check in the verifier...

llvm-svn: 45073

llvm-svn: 44997

llvm-svn: 44981

llvm-svn: 44965

2. Using zero-extended value of Scale and unsigned division is safe provided
   that Scale doesn't have the sign bit set.
   Previously these 2 instructions:
        %p = bitcast [100 x {i8,i8,i8}]* %x to i8*
        %q = getelementptr i8* %p, i32 -4
   were combined into:
        %q = getelementptr [100 x { i8, i8, i8 }]* %x, i32 0,
               i32 1431655764, i32 0
   what was incorrect.

llvm-svn: 44936

llvm-svn: 44905

Bug fix. Only safe to perform extension uses optimization if the source of extension is also defined in the same BB as the extension.

llvm-svn: 44896

Reimplement the xform in Analysis/ConstantFolding.cpp where we can use
targetdata to validate that it is safe.  While I'm in there, fix some const
correctness issues and generalize the interface to the "operand folder".

llvm-svn: 44817

on functions as it calculates them.

llvm-svn: 44802

methods are new to Function:

  bool hasCollector() const;
  const std::string &getCollector() const;
  void setCollector(const std::string &);
  void clearCollector();

The assembly representation is as such:

  define void @f() gc "shadow-stack" { ...

The implementation uses an on-the-side table to map Functions to 
collector names, such that there is no overhead. A StringPool is 
further used to unique collector names, which are extremely
likely to be unique per process.

llvm-svn: 44769

Fix several cache coherence bugs in MemDep/GVN that were found.  Also add some (disabled) debugging code
to make such problems easier to diagnose in the future, written by Duncan Sands.

llvm-svn: 44695

llvm-svn: 44655

llvm-svn: 44650

If both result of the {s|z}xt and its source are live out, rewrite all uses of the source with result of extension.

llvm-svn: 44643

throw exceptions", just mark intrinsics with the nounwind
attribute.  Likewise, mark intrinsics as readnone/readonly
and get rid of special aliasing logic (which didn't use
anything more than this anyway).

llvm-svn: 44544

llvm-svn: 44543

insert new ExitValue after this operand definition.

This fixes PR1828.

llvm-svn: 44539