memset into a single larger memset.

llvm-svn: 123086

llvm-svn: 123082

to be foldable into an uncond branch.  When this happens, we can make a
much simpler CFG for the loop, which is important for nested loop cases
where we want the outer loop to be aggressively optimized.

Handle this case more aggressively.  For example, previously on
phi-duplicate.ll we would get this:


define void @test(i32 %N, double* %G) nounwind ssp {
entry:
  %cmp1 = icmp slt i64 1, 1000
  br i1 %cmp1, label %bb.nph, label %for.end

bb.nph:                                           ; preds = %entry
  br label %for.body

for.body:                                         ; preds = %bb.nph, %for.cond
  %j.02 = phi i64 [ 1, %bb.nph ], [ %inc, %for.cond ]
  %arrayidx = getelementptr inbounds double* %G, i64 %j.02
  %tmp3 = load double* %arrayidx
  %sub = sub i64 %j.02, 1
  %arrayidx6 = getelementptr inbounds double* %G, i64 %sub
  %tmp7 = load double* %arrayidx6
  %add = fadd double %tmp3, %tmp7
  %arrayidx10 = getelementptr inbounds double* %G, i64 %j.02
  store double %add, double* %arrayidx10
  %inc = add nsw i64 %j.02, 1
  br label %for.cond

for.cond:                                         ; preds = %for.body
  %cmp = icmp slt i64 %inc, 1000
  br i1 %cmp, label %for.body, label %for.cond.for.end_crit_edge

for.cond.for.end_crit_edge:                       ; preds = %for.cond
  br label %for.end

for.end:                                          ; preds = %for.cond.for.end_crit_edge, %entry
  ret void
}

Now we get the much nicer:

define void @test(i32 %N, double* %G) nounwind ssp {
entry:
  br label %for.body

for.body:                                         ; preds = %entry, %for.body
  %j.01 = phi i64 [ 1, %entry ], [ %inc, %for.body ]
  %arrayidx = getelementptr inbounds double* %G, i64 %j.01
  %tmp3 = load double* %arrayidx
  %sub = sub i64 %j.01, 1
  %arrayidx6 = getelementptr inbounds double* %G, i64 %sub
  %tmp7 = load double* %arrayidx6
  %add = fadd double %tmp3, %tmp7
  %arrayidx10 = getelementptr inbounds double* %G, i64 %j.01
  store double %add, double* %arrayidx10
  %inc = add nsw i64 %j.01, 1
  %cmp = icmp slt i64 %inc, 1000
  br i1 %cmp, label %for.body, label %for.end

for.end:                                          ; preds = %for.body
  ret void
}

With all of these recent changes, we are now able to compile:

void foo(char *X) {
 for (int i = 0; i != 100; ++i) 
   for (int j = 0; j != 100; ++j)
     X[j+i*100] = 0;
}

into a single memset of 10000 bytes.  This series of changes
should also be helpful for other nested loop scenarios as well.

llvm-svn: 123079

1. Rip out LoopRotate's domfrontier updating code.  It isn't
   needed now that LICM doesn't use DF and it is super complex
   and gross.
2. Make DomTree updating code a lot simpler and faster.  The 
   old loop over all the blocks was just to find a block??
3. Change the code that inserts the new preheader to just use
   SplitCriticalEdge instead of doing an overcomplex 
   reimplementation of it.

No behavior change, except for the name of the inserted preheader.

llvm-svn: 123072

Add a unnamed_addr bit to global variables and functions. This will be used
to indicate that the address is not significant and therefore the constant
or function can be merged with others.

If an optimization pass can show that an address is not used, it can set this.

Examples of things that can have this set by the FE are globals created to
hold string literals and C++ constructors.

Adding unnamed_addr to a non-const global should have no effect unless
an optimization can transform that global into a constant.

Aliases are not allowed to have unnamed_addr since I couldn't figure
out any use for it.

llvm-svn: 123063

llvm-svn: 123061

them into the loop preheader, eliminating silly instructions like
"icmp i32 0, 100" in fixed tripcount loops.  This also better exposes the 
bigger problem with loop rotate that I'd like to fix: once this has been
folded, the duplicated conditional branch *often* turns into an uncond branch.

Not aggressively handling this is pessimizing later loop optimizations 
somethin' fierce by making "dominates all exit blocks" checks fail.

llvm-svn: 123060

llvm-svn: 123048

Instead encode llvm IR level property "HasSideEffects" in an operand (shared
with IsAlignStack). Added MachineInstrs::hasUnmodeledSideEffects() to check
the operand when the instruction is an INLINEASM.

This allows memory instructions to be moved around INLINEASM instructions.

llvm-svn: 123044

llvm-svn: 123039

Patch by Tim Northover.

llvm-svn: 123035

X = sext x; x >s c ? X : C+1 --> X = sext x; X <s C+1 ? C+1 : X
X = sext x; x <s c ? X : C-1 --> X = sext x; X >s C-1 ? C-1 : X
X = zext x; x >u c ? X : C+1 --> X = zext x; X <u C+1 ? C+1 : X
X = zext x; x <u c ? X : C-1 --> X = zext x; X >u C-1 ? C-1 : X
X = sext x; x >u c ? X : C+1 --> X = sext x; X <u C+1 ? C+1 : X
X = sext x; x <u c ? X : C-1 --> X = sext x; X >u C-1 ? C-1 : X

Instead of calculating this with mixed types promote all to the
larger type. This enables scalar evolution to analyze this
expression. PR8866

llvm-svn: 123034

Enable live debug variables pass.

llvm-svn: 123032

llvm-svn: 123030

Revert r122955. It seems using movups to lower memcpy can cause massive regression (even on Nehalem) in edge cases. I also didn't see any real performance benefit.

llvm-svn: 123015

Rename lisp-like functions as suggested by Gabor Greif as loooong time
ago.  This is both easier to learn and easier to read.

llvm-svn: 123001

llvm-svn: 122999

llvm-svn: 122997

Also fix an off-by-one in SelectionDAGBuilder that was preventing shuffle
vectors from being translated to EXTRACT_SUBVECTOR.
Patch by Tim Northover.

The test changes are needed to keep those spill-q tests from testing aligned
spills and restores.  If the only aligned stack objects are spill slots, we
no longer realign the stack frame.  Prior to this patch, an EXTRACT_SUBVECTOR
was legalized by loading from the stack, which created an aligned frame index.
Now, however, there is nothing except the spill slot in the stack frame, so
I added an aligned alloca.

llvm-svn: 122995

Nadav Rotem.

llvm-svn: 122983

comes back some day.

llvm-svn: 122982

llvm-svn: 122970

Patch by Richard Simth.

llvm-svn: 122962

This happens when we take the (non-constant) length from a malloc.

llvm-svn: 122961

InstCombine: If we call llvm.objectsize on a malloc call we can replace it with the size passed to malloc.

llvm-svn: 122959

llvm-svn: 122958

The theory is it's still faster than a pair of movq / a quad of movl. This
will probably hurt older chips like P4 but should run faster on current
and future Intel processors. rdar://8817010

llvm-svn: 122955

etc. takes an option OptSize. If OptSize is true, it would return
the inline limit for functions with attribute OptSize.

llvm-svn: 122952

  ret i64 ptrtoint (i8* getelementptr ([1000 x i8]* @X, i64 1, i64 sub (i64 0, i64 ptrtoint ([1000 x i8]* @X to i64))) to i64)

to "ret i64 1000".  This allows us to correctly compute the trip count
on a loop in PR8883, which occurs with std::fill on a char array.  This
allows us to transform it into a memset with a constant size.

llvm-svn: 122950

llvm-svn: 122949

llvm-svn: 122937

up freebsd bootloader. However, this doesn't make much sense for Darwin, whose
-Os is meant to optimize for size only if it doesn't hurt performance.
rdar://8821501

llvm-svn: 122936

the original type of the switch statement key.
rdar://8781238

llvm-svn: 122935

  r1025 = s/zext r1024, 4
  r1026 = extract_subreg r1025, 4
to:
  r1026 = copy r1024

llvm-svn: 122925

llvm-svn: 122921

Fix lit for people whose LLVM path contains 'opt', which is a common directory name on Unix-like systems.

llvm-svn: 122873

ashr's with huge shift amounts, PR8896

llvm-svn: 122814

This ensures that always the recently compiled tools are picked for testing.

llvm-svn: 122810

when safe.

The testcase is basically this nested loop:
void foo(char *X) {
  for (int i = 0; i != 100; ++i) 
    for (int j = 0; j != 100; ++j)
      X[j+i*100] = 0;
}

which gets turned into a single memset now.  clang -O3 doesn't optimize
this yet though due to a phase ordering issue I haven't analyzed yet.

llvm-svn: 122806

Don't pattern match "/clang" so we don't mangle directory names.  Some
tests use absolute paths to clang.

llvm-svn: 122796