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466 Commits

Author SHA1 Message Date
Devang Patel
197c35298a While hoisting common code from if/else, hoist debug info intrinsics if they match. 
llvm-svn: 129078
 2011-04-07 17:27:36 +00:00
Devang Patel
e48ddf863b Simplify. isIdenticalToWhenDefined() checks opcode. 
llvm-svn: 129041
 2011-04-07 00:30:15 +00:00
Devang Patel
d715ec82b4 While folding branch to a common destination into a predecessor, copy dbg values also. 
llvm-svn: 129035
 2011-04-06 22:37:20 +00:00
Jay Foad
52131344a2 Remove PHINode::reserveOperandSpace(). Instead, add a parameter to 
PHINode::Create() giving the (known or expected) number of operands.

llvm-svn: 128537
 2011-03-30 11:28:46 +00:00
Jay Foad
e0938d8a87 (Almost) always call reserveOperandSpace() on newly created PHINodes. 
llvm-svn: 128535
 2011-03-30 11:19:20 +00:00
Eli Friedman
c4414c6e92 PR9450: Make switch optimization in SimplifyCFG not dependent on the ordering 
of pointers in an std::map.

llvm-svn: 127650
 2011-03-15 02:23:35 +00:00
Eli Friedman
aac35b3fbb PR9420; an instruction before an unreachable is guaranteed not to have any 
reachable uses, but there still might be uses in dead blocks.  Use the
standard solution of replacing all the uses with undef.  This is
a rare case because it's very sensitive to phase ordering in SimplifyCFG.

llvm-svn: 127299
 2011-03-09 00:48:33 +00:00
Frits van Bommel
8ae07996c9 Teach SimplifyCFG that (switch (select cond, X, Y)) is better expressed as a branch. 
Based on a patch by Alistair Lynn.

llvm-svn: 126647
 2011-02-28 09:44:07 +00:00
Benjamin Kramer
ceb5daa567 Revert "SimplifyCFG: GEPs with just one non-constant index are also cheap." 
Yes, there are other types than i8* and GEPs on them can produce an add+multiply.
We don't consider that cheap enough to be speculatively executed.

llvm-svn: 126481
 2011-02-25 10:33:33 +00:00
Benjamin Kramer
dfdca1a14d SimplifyCFG: GEPs with just one non-constant index are also cheap. 
llvm-svn: 126452
 2011-02-24 23:26:09 +00:00
Benjamin Kramer
27361a7124 SimplifyCFG: GEPs with constant indices are cheap enough to be executed unconditionally. 
llvm-svn: 126445
 2011-02-24 22:46:11 +00:00
Benjamin Kramer
8d6a8c130b SimplifyCFG: Track the number of used icmps when turning a icmp chain into a switch. If we used only one icmp, don't turn it into a switch. 
Also prevent the switch-to-icmp transform from creating identity adds, noticed by Marius Wachtler.

llvm-svn: 125056
 2011-02-07 22:37:28 +00:00
Benjamin Kramer
62aa46b852 SimplifyCFG: Also transform switches that represent a range comparison but are not sorted into sub+icmp. 
This transforms another 1000 switches in gcc.c.

llvm-svn: 124826
 2011-02-03 22:51:41 +00:00
Benjamin Kramer
f4ea1d5f79 SimplifyCFG: Turn switches into sub+icmp+branch if possible. 
This makes the job of the later optzn passes easier, allowing the vast amount of
icmp transforms to chew on it.

We transform 840 switches in gcc.c, leading to a 16k byte shrink of the resulting
binary on i386-linux.

The testcase from README.txt now compiles into
  decl  %edi
  cmpl  $3, %edi
  sbbl  %eax, %eax
  andl  $1, %eax
  ret

llvm-svn: 124724
 2011-02-02 15:56:22 +00:00
Evan Cheng
d983eba7dc Re-apply r124518 with fix. Watch out for invalidated iterator. 
llvm-svn: 124526
 2011-01-29 04:46:23 +00:00
Evan Cheng
65b8ccf6ac Revert r124518. It broke Linux self-host. 
llvm-svn: 124522
 2011-01-29 02:43:04 +00:00
Evan Cheng
d4eff31476 Re-commit r124462 with fixes. Tail recursion elim will now dup ret into unconditional predecessor to enable TCE on demand. 
llvm-svn: 124518
 2011-01-29 01:29:26 +00:00
Evan Cheng
aaa9606b2f Revert r124462. There are a few big regressions that I need to fix first. 
llvm-svn: 124478
 2011-01-28 07:12:38 +00:00
Evan Cheng
417fca86c4 - Stop simplifycfg from duplicating "ret" instructions into unconditional 
branches. PR8575, rdar://5134905, rdar://8911460.
- Allow codegen tail duplication to dup small return blocks after register
  allocation is done.

llvm-svn: 124462
 2011-01-28 02:19:21 +00:00
Frits van Bommel
8e158495f1 Factor the actual simplification out of SimplifyIndirectBrOnSelect and into a new helper function so it can be reused in e.g. an upcoming SimplifySwitchOnSelect. 
No functional change.

llvm-svn: 123234
 2011-01-11 12:52:11 +00:00
Chris Lattner
6b8b4855ff simplify this a bit. 
llvm-svn: 122156
 2010-12-18 20:22:49 +00:00
Benjamin Kramer
e5f49c4ff2 SimplifyCFG: Ranges can be larger than 64 bits. Fixes Release-selfhost build. 
llvm-svn: 122054
 2010-12-17 10:48:14 +00:00
Chris Lattner
d14b0f1db7 improve switch formation to handle small range 
comparisons formed by comparisons.  For example,
this:

void foo(unsigned x) {
  if (x == 0 || x == 1 || x == 3 || x == 4 || x == 6) 
    bar();
}

compiles into:

_foo:                                   ## @foo
## BB#0:                                ## %entry
	cmpl	$6, %edi
	ja	LBB0_2
## BB#1:                                ## %entry
	movl	%edi, %eax
	movl	$91, %ecx
	btq	%rax, %rcx
	jb	LBB0_3

instead of:

_foo:                                   ## @foo
## BB#0:                                ## %entry
	cmpl	$2, %edi
	jb	LBB0_4
## BB#1:                                ## %switch.early.test
	cmpl	$6, %edi
	ja	LBB0_3
## BB#2:                                ## %switch.early.test
	movl	%edi, %eax
	movl	$88, %ecx
	btq	%rax, %rcx
	jb	LBB0_4

This catches a bunch of cases in GCC, which look like this:

 %804 = load i32* @which_alternative, align 4, !tbaa !0
 %805 = icmp ult i32 %804, 2
 %806 = icmp eq i32 %804, 3
 %or.cond121 = or i1 %805, %806
 %807 = icmp eq i32 %804, 4
 %or.cond124 = or i1 %or.cond121, %807
 br i1 %or.cond124, label %.thread, label %808

turning this into a range comparison.

llvm-svn: 122045
 2010-12-17 06:20:15 +00:00
Chris Lattner
e893e2601e make qsort predicate more conformant by returning 0 for equal values. 
llvm-svn: 121838
 2010-12-15 04:52:41 +00:00
Chris Lattner
7499b452c1 - Insert new instructions before DomBlock's terminator, 
which is simpler than finding a place to insert in BB.
 - Don't perform the 'if condition hoisting' xform on certain
   i1 PHIs, as it interferes with switch formation.

This re-fixes "example 7", without breaking the world hopefully.

llvm-svn: 121764
 2010-12-14 08:46:09 +00:00
Chris Lattner
335f0e4ad4 fix two significant issues with FoldTwoEntryPHINode: 
first, it can kick in on blocks whose conditions have been
folded to a constant, even though one of the edges will be
trivially folded.

second, it doesn't clean up the "if diamond" that it just 
eliminated away.  This is a problem because other simplifycfg
xforms kick in depending on the order of block visitation,
causing pointless work.

llvm-svn: 121762
 2010-12-14 08:01:53 +00:00
Chris Lattner
dc20a7d38c remove the instsimplify logic I added in r121754. It is apparently 
breaking the selfhost builds, though I can't fathom how.

llvm-svn: 121761
 2010-12-14 07:53:03 +00:00
Chris Lattner
9ac168d0ab clean up logic, convert std::set to SmallPtrSet, handle the case 
when all 2-entry phis are simplified away.

llvm-svn: 121760
 2010-12-14 07:41:39 +00:00
Chris Lattner
9fd838d31b tidy up a bit, move DEBUG down to when we commit to doing the transform so we 
don't print it unless the xform happens.

llvm-svn: 121758
 2010-12-14 07:23:10 +00:00
Chris Lattner
b42d293faa use SimplifyInstruction instead of reimplementing part of it. 
llvm-svn: 121757
 2010-12-14 07:20:29 +00:00
Chris Lattner
fb73de482c simplify GetIfCondition by using getSinglePredecessor. 
llvm-svn: 121756
 2010-12-14 07:15:21 +00:00
Chris Lattner
0f4d67bd88 use AddPredecessorToBlock in 3 places instead of a manual loop. 
llvm-svn: 121755
 2010-12-14 07:09:42 +00:00
Chris Lattner
a07cc6f4fd make FoldTwoEntryPHINode use instsimplify a bit, make 
GetIfCondition faster by avoiding pred_iterator.  No
really interesting change.

llvm-svn: 121754
 2010-12-14 07:00:00 +00:00
Chris Lattner
d7beca3782 improve DEBUG's a bit, switch to eraseFromParent() to simplify 
code a bit, switch from constant folding to instsimplify.

llvm-svn: 121751
 2010-12-14 06:17:25 +00:00
Chris Lattner
5a9d59d918 reapply my recent change that disables a piece of the switch formation 
work, but fixes 400.perlbmk.

llvm-svn: 121749
 2010-12-14 05:57:30 +00:00
Owen Anderson
3e5648896e Fix recent buildbot breakage by pulling SimplifyCFG back to its state as of r121694, the most recent state 
where I'm confident there were no crashes or miscompilations.  XFAIL the test added since then for now.

llvm-svn: 121733
 2010-12-13 23:49:28 +00:00
Chris Lattner
a6e5d5694a temporarily disable part of my previous patch, which causes an iterator invalidation issue, causing a crash on some versions of perlbmk. 
llvm-svn: 121728
 2010-12-13 23:02:19 +00:00
Chris Lattner
2d434e594e add some DEBUG's. 
llvm-svn: 121711
 2010-12-13 19:55:30 +00:00
Benjamin Kramer
1e155ab7e1 Fix sort predicate. qsort(3)'s predicate semantics differ from std::sort's. Fixes PR 8780. 
llvm-svn: 121705
 2010-12-13 18:20:38 +00:00
Chris Lattner
fb836f8c1a reinstate my patch: the miscompile was caused by an inverted branch in the 
'and' case.

llvm-svn: 121695
 2010-12-13 08:12:19 +00:00
Chris Lattner
79db357d80 Completely disable the optimization I added in r121680 until 
I can track down a miscompile.  This should bring the buildbots
back to life

llvm-svn: 121693
 2010-12-13 07:41:29 +00:00
Chris Lattner
fbeb55844b Make simplifycfg reprocess newly formed "br (cond1 | cond2)" conditions 
when simplifying, allowing them to be eagerly turned into switches.  This
is the last step required to get "Example 7" from this blog post:
http://blog.regehr.org/archives/320

On X86, we now generate this machine code, which (to my eye) seems better
than the ICC generated code:

_crud:                                  ## @crud
## BB#0:                                ## %entry
	cmpb	$33, %dil
	jb	LBB0_4
## BB#1:                                ## %switch.early.test
	addb	$-34, %dil
	cmpb	$58, %dil
	ja	LBB0_3
## BB#2:                                ## %switch.early.test
	movzbl	%dil, %eax
	movabsq	$288230376537592865, %rcx ## imm = 0x400000017001421
	btq	%rax, %rcx
	jb	LBB0_4
LBB0_3:                                 ## %lor.rhs
	xorl	%eax, %eax
	ret
LBB0_4:                                 ## %lor.end
	movl	$1, %eax
	ret

llvm-svn: 121690
 2010-12-13 07:00:06 +00:00
Chris Lattner
1d05761df4 make this logic a bit simpler. 
llvm-svn: 121689
 2010-12-13 06:36:51 +00:00
Chris Lattner
25c3af35d8 split all the guts of SimplifyCFGOpt::run out into one function 
per terminator kind.

llvm-svn: 121688
 2010-12-13 06:25:44 +00:00
Chris Lattner
cb570f87e5 fix a bug in r121680 that upset the various buildbots. 
llvm-svn: 121687
 2010-12-13 05:34:18 +00:00
Chris Lattner
a6db741f3d refactor the speculative execution logic to be factored into the cond branch code instead of 
doing a cfg search for every block simplified.

llvm-svn: 121686
 2010-12-13 05:26:52 +00:00
Chris Lattner
466f54ffcf simplify a bunch of code. 
llvm-svn: 121685
 2010-12-13 05:20:28 +00:00
Chris Lattner
6df7bdd810 move HoistThenElseCodeToIf up to a more logical and efficient-to-handle place. 
llvm-svn: 121684
 2010-12-13 05:15:29 +00:00
Chris Lattner
2e3832d9a0 move 'MergeBlocksIntoPredecessor' call earlier. Use 
getSinglePredecessor to simplify code.

llvm-svn: 121683
 2010-12-13 05:10:48 +00:00
Chris Lattner
a69c443459 factor new code out to a SimplifyBranchOnICmpChain helper function. 
llvm-svn: 121681
 2010-12-13 05:03:41 +00:00
Chris Lattner
a442f24a36 enhance the "change or icmp's into switch" xform to handle one value in an 
'or sequence' that it doesn't understand.  This allows us to optimize
something insane like this:

int crud (unsigned char c, unsigned x)
 {
   if(((((((((( (int) c <= 32 ||
                    (int) c == 46) || (int) c == 44)
                  || (int) c == 58) || (int) c == 59) || (int) c == 60)
               || (int) c == 62) || (int) c == 34) || (int) c == 92)
            || (int) c == 39) != 0)
     foo();
 }

into:

define i32 @crud(i8 zeroext %c, i32 %x) nounwind ssp noredzone {
entry:
  %cmp = icmp ult i8 %c, 33
  br i1 %cmp, label %if.then, label %switch.early.test

switch.early.test:                                ; preds = %entry
  switch i8 %c, label %if.end [
    i8 39, label %if.then
    i8 44, label %if.then
    i8 58, label %if.then
    i8 59, label %if.then
    i8 60, label %if.then
    i8 62, label %if.then
    i8 46, label %if.then
    i8 92, label %if.then
    i8 34, label %if.then
  ]

by pulling the < comparison out ahead of the newly formed switch.

llvm-svn: 121680
 2010-12-13 04:50:38 +00:00
Chris Lattner
5a177e681e merge two very similar functions into one that has a bool argument. 
llvm-svn: 121678
 2010-12-13 04:26:26 +00:00
Chris Lattner
9b1af510cb don't bother handling non-canonical icmp's 
llvm-svn: 121676
 2010-12-13 04:18:32 +00:00
Chris Lattner
395252d93e inline a function, making the result much simpler. 
llvm-svn: 121675
 2010-12-13 04:15:19 +00:00
Chris Lattner
62cc76e9cc Fix my previous patch to handle a degenerate case that the llvm-gcc 
bootstrap buildbot tripped over.

llvm-svn: 121674
 2010-12-13 03:43:57 +00:00
Chris Lattner
11dafaa3ec convert some methods to be static functions 
llvm-svn: 121673
 2010-12-13 03:30:12 +00:00
Chris Lattner
4642d79fb0 zap two more std::sorts. 
llvm-svn: 121672
 2010-12-13 03:24:30 +00:00
Chris Lattner
d9bacc088a fix a fairly serious oversight with switch formation from 
or'd conditions.  Previously we'd compile something like this:

int crud (unsigned char c) {
   return c == 62 || c == 34 || c == 92;
}

into:

  switch i8 %c, label %lor.rhs [
    i8 62, label %lor.end
    i8 34, label %lor.end
  ]

lor.rhs:                                          ; preds = %entry
  %cmp8 = icmp eq i8 %c, 92
  br label %lor.end

lor.end:                                          ; preds = %entry, %entry, %lor.rhs
  %0 = phi i1 [ true, %entry ], [ %cmp8, %lor.rhs ], [ true, %entry ]
  %lor.ext = zext i1 %0 to i32
  ret i32 %lor.ext

which failed to merge the compare-with-92 into the switch.  With this patch
we simplify this all the way to:

  switch i8 %c, label %lor.rhs [
    i8 62, label %lor.end
    i8 34, label %lor.end
    i8 92, label %lor.end
  ]

lor.rhs:                                          ; preds = %entry
  br label %lor.end

lor.end:                                          ; preds = %entry, %entry, %entry, %lor.rhs
  %0 = phi i1 [ true, %entry ], [ false, %lor.rhs ], [ true, %entry ], [ true, %entry ]
  %lor.ext = zext i1 %0 to i32
  ret i32 %lor.ext

which is much better for codegen's switch lowering stuff.  This kicks in 33 times
on 176.gcc (for example) cutting 103 instructions off the generated code.

llvm-svn: 121671
 2010-12-13 03:18:54 +00:00
Chris Lattner
7c8e6047d6 convert an std::sort to array_pod_sort. 
llvm-svn: 121669
 2010-12-13 02:00:58 +00:00
Chris Lattner
1475987634 move the "br (X == 0 | X == 1), T, F" -> switch optimization to a new 
location in simplifycfg.  In the old days, SimplifyCFG was never run on
the entry block, so we had to scan over all preds of the BB passed into
simplifycfg to do this xform, now we can just check blocks ending with
a condbranch.  This avoids a scan over all preds of every simplified 
block, which should be a significant compile-time perf win on functions
with lots of edges.  No functionality change.

llvm-svn: 121668
 2010-12-13 01:57:34 +00:00
Chris Lattner
4088e2b8e4 reduce indentation and generally simplify code, no functionality change. 
llvm-svn: 121667
 2010-12-13 01:47:07 +00:00
Chris Lattner
7cb7867d7a use getFirstNonPHIOrDbg to simplify this code. 
llvm-svn: 121664
 2010-12-13 01:28:06 +00:00
Frits van Bommel
8fb69ee805 Teach SimplifyCFG to turn 
(indirectbr (select cond, blockaddress(@fn, BlockA),
                            blockaddress(@fn, BlockB)))
into
  (br cond, BlockA, BlockB).

llvm-svn: 120943
 2010-12-05 18:29:03 +00:00
Duncan Sands
31c803b2ba Fix PR8445: a block with no predecessors may be the entry block, in which case 
it isn't unreachable and should not be zapped.  The check for the entry block
was missing in one case: a block containing a unwind instruction.  While there,
do some small cleanups: "M" is not a great name for a Function* (it would be
more appropriate for a Module*), change it to "Fn"; use Fn in more places.

llvm-svn: 117224
 2010-10-24 12:23:30 +00:00
Dan Gohman
250b754428 Instead, teach SimplifyCFG to trim non-address-taken blocks from 
indirectbr destination lists.

llvm-svn: 111122
 2010-08-16 14:41:14 +00:00
Dan Gohman
4a63fad976 Teach SimplifyCFG how to simplify indirectbr instructions. 
- Eliminate redundant successors.
 - Convert an indirectbr with one successor into a direct branch.

Also, generalize SimplifyCFG to be able to be run on a function entry block.
It knows quite a few simplifications which are applicable to the entry
block, and it only needs a few checks to avoid trouble with the entry block.

llvm-svn: 111060
 2010-08-14 00:29:42 +00:00
Gabor Greif
36f25dfd33 pass dereferenced iterator to dyn_cast 
llvm-svn: 109098
 2010-07-22 11:43:44 +00:00
Owen Anderson
13700ebb02 Remove unneeded check, and correct style. 
llvm-svn: 108427
 2010-07-15 16:38:22 +00:00
Owen Anderson
2cfe91379b Extend SimplifyCFG's common-destination folding heuristic to allow a single 
"bonus" instruction to be speculatively executed.  Add a heuristic to
ensure we're not tripping up out-of-order execution by checking that this bonus
instruction only uses values that were already guaranteed to be available.

This allows us to eliminate the short circuit in (x&1)&&(x&2).

llvm-svn: 108351
 2010-07-14 19:52:16 +00:00
Gabor Greif
8629f12bb8 cache dereferenced iterators 
llvm-svn: 108133
 2010-07-12 10:59:23 +00:00
Gabor Greif
329c4d8ed9 cache result of operator* 
llvm-svn: 107974
 2010-07-09 15:25:09 +00:00
Dan Gohman
39027c403c Fix a grammaro. 
llvm-svn: 99917
 2010-03-30 20:04:57 +00:00
Gabor Greif
b469818279 fix two cases where the arguments were extracted from the wrong range out of the InvokeInst 
spotted by baldrick -- thanks\!

llvm-svn: 99914
 2010-03-30 19:20:53 +00:00
Bill Wendling
ee84f27536 Make returns more consistent with others. 
llvm-svn: 98490
 2010-03-14 10:40:28 +00:00
Duncan Sands
19d0b47b1f There are two ways of checking for a given type, for example isa<PointerType>(T) 
and T->isPointerTy().  Convert most instances of the first form to the second form.
Requested by Chris.

llvm-svn: 96344
 2010-02-16 11:11:14 +00:00
Duncan Sands
9dff9bec31 Uniformize the names of type predicates: rather than having isFloatTy and 
isInteger, we now have isFloatTy and isIntegerTy.  Requested by Chris!

llvm-svn: 96223
 2010-02-15 16:12:20 +00:00
Jakob Stoklund Olesen
916f48a054 Teach SimplifyCFG about magic pointer constants. 
Weird code sometimes uses pointer constants other than null. This patch
teaches SimplifyCFG to build switch instructions in those cases.

Code like this:

void f(const char *x) {
  if (!x)
    puts("null");
  else if ((uintptr_t)x == 1)
    puts("one");
  else if (x == (char*)2 || x == (char*)3)
    puts("two");
  else if ((intptr_t)x == 4)
    puts("four");
  else
    puts(x);
}

Now becomes a switch:

define void @f(i8* %x) nounwind ssp {
entry:
  %magicptr23 = ptrtoint i8* %x to i64            ; <i64> [#uses=1]
  switch i64 %magicptr23, label %if.else16 [
    i64 0, label %if.then
    i64 1, label %if.then2
    i64 2, label %if.then9
    i64 3, label %if.then9
    i64 4, label %if.then14
  ]

Note that LLVM's own DenseMap uses magic pointers.

llvm-svn: 95439
 2010-02-05 22:03:18 +00:00
Benjamin Kramer
a81a6dff0d Convert a ton of simple integer type equality tests to the new predicate. 
llvm-svn: 92760
 2010-01-05 20:07:06 +00:00
Benjamin Kramer
ccce8bae14 Avoid going through the LLVMContext for type equality where it's safe to dereference the type pointer. 
llvm-svn: 92726
 2010-01-05 13:12:22 +00:00
David Greene
725c7c3f2e Change errs() to dbgs(). 
llvm-svn: 92604
 2010-01-05 01:26:52 +00:00
Devang Patel
be94f23992 Remove dead debug info intrinsics. 
Intrinsic::dbg_stoppoint
 Intrinsic::dbg_region_start 
 Intrinsic::dbg_region_end 
 Intrinsic::dbg_func_start
AutoUpgrade simply ignores these intrinsics now.

llvm-svn: 92557
 2010-01-05 01:10:40 +00:00
Jim Grosbach
d831ef4945 Move EliminateDuplicatePHINodes() from SimplifyCFG.cpp to Local.cpp 
llvm-svn: 90324
 2009-12-02 17:06:45 +00:00
Jim Grosbach
cc69a1ba9a Make EliminateDuplicatePHINodes() available as a utility function 
llvm-svn: 89297
 2009-11-19 02:02:10 +00:00
Chris Lattner
cbd18fc93d refactor TryToSimplifyUncondBranchFromEmptyBlock out of SimplifyCFG. 
llvm-svn: 86666
 2009-11-10 05:59:26 +00:00
Chris Lattner
46b5c642b9 remove a bunch of extraneous LLVMContext arguments 
from various APIs, addressing PR5325.

llvm-svn: 86231
 2009-11-06 04:27:31 +00:00
Dan Gohman
7f7d97eb73 Add a comment about a missed opportunity. 
llvm-svn: 85635
 2009-10-30 23:15:43 +00:00
Dan Gohman
1a95106602 Teach SimplifyCFG how to eliminate duplicate PHI nodes within a block. 
This reduces codesize on a variety of codes by 1-2% on x86-64. It also
helps clean up after SSAUpdater.

llvm-svn: 85626
 2009-10-30 22:39:04 +00:00
Chris Lattner
19788ca686 change simplifycfg to not duplicate 'unwind' instructions. Hopefully 
this will increase the likelihood of common code getting sunk towards
the unwind.

llvm-svn: 83996
 2009-10-13 18:13:05 +00:00
Nick Lewycky
42fb7452df Instruction::clone does not need to take an LLVMContext&. Remove that and 
update all the callers.

llvm-svn: 82889
 2009-09-27 07:38:41 +00:00
Dan Gohman
c8a27f2a5c Rename Instruction::isIdenticalTo to Instruction::isIdenticalToWhenDefined, 
and introduce a new Instruction::isIdenticalTo which tests for full
identity, including the SubclassOptionalData flags. Also, fix the
Instruction::clone implementations to preserve the SubclassOptionalData
flags. Finally, teach several optimizations how to handle
SubclassOptionalData correctly, given these changes.

This fixes the counterintuitive behavior of isIdenticalTo not comparing
the full value, and clone not returning an identical clone, as well as
some subtle bugs that could be caused by these.

Thanks to Nick Lewycky for reporting this, and for an initial patch!

llvm-svn: 80038
 2009-08-25 22:11:20 +00:00
Daniel Dunbar
5e0a58bef4 Fix -Asserts warnings. 
llvm-svn: 79849
 2009-08-23 10:29:55 +00:00
Chris Lattner
b25de3ff60 eliminate the "Value" printing methods that print to a std::ostream. 
This required converting a bunch of stuff off DOUT and other cleanups.

llvm-svn: 79819
 2009-08-23 04:37:46 +00:00
Eli Friedman
d56fca4708 Fix for PR3016: detect the tricky case, where there are 
unfoldable references to a PHI node in the block being folded, and disable
the transformation in that case.  The correct transformation of such PHI
nodes depends on whether BB dominates Succ, and dominance is expensive 
to compute here.  (Alternatively, it's possible to check whether any 
uses are live, but that's also essentially a dominance calculation. 
Another alternative is to use reg2mem, but it probably isn't a good idea to
use that in simplifycfg.)

Also, remove some incorrect code from CanPropagatePredecessorsForPHIs 
which is made unnecessary with this patch: it didn't consider the case 
where a PHI node in BB has multiple uses.

llvm-svn: 79174
 2009-08-16 04:23:49 +00:00
Owen Anderson
55f1c09e31 Push LLVMContexts through the IntegerType APIs. 
llvm-svn: 78948
 2009-08-13 21:58:54 +00:00
Dan Gohman
5476cfdb15 Remove a bunch more now-unnecessary Context arguments. 
llvm-svn: 78809
 2009-08-12 16:23:25 +00:00
Owen Anderson
b292b8ce70 Move more code back to 2.5 APIs. 
llvm-svn: 77635
 2009-07-30 23:03:37 +00:00
Daniel Dunbar
6115b39ffd Remove Value::getName{Start,End}, the last of the old Name APIs. 
llvm-svn: 77152
 2009-07-26 09:48:23 +00:00
Daniel Dunbar
0dd5e1ed39 More migration to raw_ostream, the water has dried up around the iostream hole. 
- Some clients which used DOUT have moved to DEBUG. We are deprecating the
   "magic" DOUT behavior which avoided calling printing functions when the
   statement was disabled. In addition to being unnecessary magic, it had the
   downside of leaving code in -Asserts builds, and of hiding potentially
   unnecessary computations.

llvm-svn: 77019
 2009-07-25 00:23:56 +00:00
Owen Anderson
edb4a70325 Revert the ConstantInt constructors back to their 2.5 forms where possible, thanks to contexts-on-types. More to come. 
llvm-svn: 77011
 2009-07-24 23:12:02 +00:00
Owen Anderson
47db941fd3 Get rid of the Pass+Context magic. 
llvm-svn: 76702
 2009-07-22 00:24:57 +00:00
Eli Friedman
b8f6a4fc8e Replace isTrapping with a new, similar method called 
isSafeToSpeculativelyExecute. The new method is a bit closer to what 
the callers actually care about in that it rejects more things callers 
don't want.  It also adds more precise handling for integer 
division, and unifies code for analyzing the legality of a speculative 
load.

llvm-svn: 76150
 2009-07-17 04:28:42 +00:00
Owen Anderson
542619e6d5 Move more functionality over to LLVMContext. 
llvm-svn: 75497
 2009-07-13 20:58:05 +00:00
Owen Anderson
1e5f00e7a7 This started as a small change, I swear. Unfortunately, lots of things call the [I|F]CmpInst constructors. Who knew!? 
llvm-svn: 75200
 2009-07-09 23:48:35 +00:00
Owen Anderson
38264b1554 "LLVMContext* " --> "LLVMContext *" 
llvm-svn: 74878
 2009-07-06 23:00:19 +00:00
Owen Anderson
39f00cc1d4 Thread LLVMContext through the constant folding APIs, which touches a lot of files. 
llvm-svn: 74844
 2009-07-06 18:42:36 +00:00
Owen Anderson
e70b637033 More LLVMContext-ification. 
llvm-svn: 74807
 2009-07-05 22:41:43 +00:00
Dan Gohman
c8ca49659a Teach LoopSimplify how to merge multiple loop exits into a single exit, 
when one of them can be converted to a trivial icmp and conditional
branch.

This addresses what is essentially a phase ordering problem.
SimplifyCFG knows how to do this transformation, but it doesn't do so
if the primary block has any instructions in it other than an icmp and
a branch. In the given testcase, the block contains other instructions,
however they are loop-invariant and can be hoisted. SimplifyCFG doesn't
have LoopInfo though, so it can't hoist them. And, it's important that
the blocks be merged before LoopRotation, as it doesn't support
multiple-exit loops.

llvm-svn: 74396
 2009-06-27 21:30:38 +00:00
Dale Johannesen
9df78ee1ae Fix the crash in this test. This is basically the same 
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
 2009-06-15 20:59:27 +00:00
Dan Gohman
a5b9645c4b Split the Add, Sub, and Mul instruction opcodes into separate 
integer and floating-point opcodes, introducing
FAdd, FSub, and FMul.

For now, the AsmParser, BitcodeReader, and IRBuilder all preserve
backwards compatability, and the Core LLVM APIs preserve backwards
compatibility for IR producers. Most front-ends won't need to change
immediately.

This implements the first step of the plan outlined here:
http://nondot.org/sabre/LLVMNotes/IntegerOverflow.txt

llvm-svn: 72897
 2009-06-04 22:49:04 +00:00
Dale Johannesen
1ac1969e09 Reuse existing getUnderlyingObject instead of 
adding another copy.

llvm-svn: 71783
 2009-05-14 18:41:18 +00:00
Dale Johannesen
3181652363 Handle some additonal cases of external weak globals. 
llvm-svn: 71717
 2009-05-13 20:55:30 +00:00
Dale Johannesen
69921959b4 Don't generate a select whose operand is load of a weak 
external.  These may have address 0 and are not safe
to execute unconditionally.

llvm-svn: 71688
 2009-05-13 18:25:07 +00:00
Dan Gohman
9a6fef0a52 Simplify code by using SmallVector's pop_back_val() instead of 
separate back() and pop_back() calls.

llvm-svn: 71089
 2009-05-06 17:22:41 +00:00
Dale Johannesen
e4f361212b Fix comment typo. 
llvm-svn: 67307
 2009-03-19 17:23:29 +00:00
Dale Johannesen
cecfa6e08d Fix one more place where debug info affected 
codegen (speculative execution).

llvm-svn: 66859
 2009-03-13 01:05:24 +00:00
Dale Johannesen
ed6f5a8253 Previous debug info fix to this code wasn't quite 
right; did the wrong thing when there are exactly 11
non-debug instructions, followed by debug info.
Remove a FIXME since it's apparently been fixed along the way.

llvm-svn: 66840
 2009-03-12 23:18:09 +00:00
Dale Johannesen
7f99d22f2f There already was a class to force deterministic 
sorting of ConstantInt's; unreinvent wheel.

llvm-svn: 66824
 2009-03-12 21:01:11 +00:00
Dale Johannesen
578d8bfc3c Another missing check for debug intrinsics. 
llvm-svn: 66800
 2009-03-12 17:42:45 +00:00
Dale Johannesen
9cdb9bb3e5 Allow for switch values bigger than 64 bits. 
llvm-svn: 66751
 2009-03-12 01:20:06 +00:00
Dale Johannesen
5a41b2def5 Fix some nondeterministic behavior when forwarding 
from a switch table.  Multiple table entries that
branch to the same place were being sorted by the
pointer value of the ConstantInt*; changed to sort
by the actual value of the ConstantInt.

llvm-svn: 66749
 2009-03-12 01:00:26 +00:00
Devang Patel
84fceff969 Ignore dbg info, while estimating size of jump through block. 
llvm-svn: 66554
 2009-03-10 18:00:05 +00:00
Dale Johannesen
6e447e08ee Fix another case where debug info interferes with 
an optimization.

llvm-svn: 66288
 2009-03-06 21:08:33 +00:00
Devang Patel
5aed7765b8 While hoisting instruction to speculatively execute simple bb, ignore dbg intrinsics. 
llvm-svn: 66255
 2009-03-06 06:00:17 +00:00
Bill Wendling
7fcd6148f7 Remove accidental check-ins in r65960. :-( 
llvm-svn: 65961
 2009-03-03 19:25:16 +00:00
Bill Wendling
a68fc7af63 Use > instead of >=. We want to promote aggregates of 128-bytes. 
llvm-svn: 65960
 2009-03-03 19:18:49 +00:00
Zhou Sheng
264e46e1e9 Ignore dbg info intrinsics when folding conditional branch to 
conditional branch predecessors.

llvm-svn: 65509
 2009-02-26 06:56:37 +00:00
Zhou Sheng
5d9cc1763b Don't block basic block with only SwitchInst to fold into predecessors. 
llvm-svn: 65456
 2009-02-25 15:34:27 +00:00
Devang Patel
e288082644 While folding unconditional return move DbgRegionEndInst into the predecessor, instead of removing it. This fixes following tests from llvmgcc42 testsuite. 
gcc.c-torture/execute/20000605-3.c
gcc.c-torture/execute/20020619-1.c
gcc.c-torture/execute/20030920-1.c
gcc.c-torture/execute/loop-ivopts-1.c

llvm-svn: 65353
 2009-02-24 00:05:16 +00:00
Devang Patel
316705027b If llvm.dbg.region.end is disappearing then remove corresponding llvm.dbg.func.start also. 
llvm-svn: 64278
 2009-02-11 01:29:06 +00:00
Devang Patel
654e47f366 Ignore dbg intrinsic while folding unconditional branch. 
llvm-svn: 64242
 2009-02-10 22:14:17 +00:00
Devang Patel
02f58e1e8d Revert rev. 63876. It is causing llvm-gcc bootstrap failure. 
llvm-svn: 63888
 2009-02-05 21:46:41 +00:00
Devang Patel
5922e26d1a Ignore dbg intrinsics while propagating conditional expression info. 
llvm-svn: 63876
 2009-02-05 19:15:39 +00:00
Devang Patel
086b212277 Ignore dbg intrinsics while folding switch instruction. 
llvm-svn: 63802
 2009-02-05 00:30:42 +00:00
Devang Patel
916fdce16d Ignore dbg intrinsics. 
llvm-svn: 63781
 2009-02-04 21:39:48 +00:00
Devang Patel
fd9f635103 While folding vallue comparison terminators ignore dbg intrinsics. 
llvm-svn: 63700
 2009-02-04 01:06:11 +00:00
Devang Patel
f10e287c65 Ignore dbg intrinsics while hoisting common code in the two blocks up into the branch block. 
llvm-svn: 63687
 2009-02-04 00:03:08 +00:00
Devang Patel
2032cadd0f Do not let dbg intrinsic block folding of two entry phi node. 
llvm-svn: 63671
 2009-02-03 22:12:02 +00:00
Chris Lattner
c59945b4bd another fix for PR3354 
llvm-svn: 62561
 2009-01-20 01:15:41 +00:00
Bill Wendling
caf1d22243 Doxygen-ify comments. 
llvm-svn: 62546
 2009-01-19 23:43:56 +00:00
Chris Lattner
ea9f1d3c47 Fix a problem exposed by PR3354: simplifycfg was making a potentially 
trapping instruction be executed unconditionally.

llvm-svn: 62541
 2009-01-19 23:03:13 +00:00
Bill Wendling
534d2e0bae Temporarily revert r62487. It's causing this error during a release bootstrap of 
llvm-gcc. Most likely, it's miscompiling one of the "gen*" programs:

/Volumes/Sandbox/Buildbot/llvm/full-llvm/build/llvm-gcc.obj/./prev-gcc/xgcc -B/Volumes/Sandbox/Buildbot/llvm/full-llvm/build/llvm-gcc.obj/./prev-gcc/ -B/Volumes/Sandbox/Buildbot/llvm/full-llvm/build/llvm-gcc.install/i386-apple-darwin9.6.0/bin/ -c -g -O2 -mdynamic-no-pic -DIN_GCC -W -Wall -Wwrite-strings -Wstrict-prototypes -Wmissing-prototypes -mdynamic-no-pic -DHAVE_CONFIG_H -DGENERATOR_FILE -I. -Ibuild -I../../llvm-gcc.src/gcc -I../../llvm-gcc.src/gcc/build -I../../llvm-gcc.src/gcc/../include -I./../intl -I../../llvm-gcc.src/gcc/../libcpp/include  -I../../llvm-gcc.src/gcc/../libdecnumber -I../libdecnumber -I/Volumes/Sandbox/Buildbot/llvm/full-llvm/build/llvm.obj/include -I/Volumes/Sandbox/Buildbot/llvm/full-llvm/build/llvm.src/include -DENABLE_LLVM -I/Volumes/Sandbox/Buildbot/llvm/full-llvm/build/llvm.obj/../llvm.src/include  -D_DEBUG  -D_GNU_SOURCE -D__STDC_LIMIT_MACROS -D__STDC_CONSTANT_MACROS   -o build/gencondmd.o build/gencondmd.c
../../llvm-gcc.src/gcc/config/i386/mmx.md:926: error: expected '}' before ')' token
../../llvm-gcc.src/gcc/config/i386/mmx.md:926: warning: excess elements in struct initializer
../../llvm-gcc.src/gcc/config/i386/mmx.md:926: warning: (near initialization for 'insn_conditions[4]')
../../llvm-gcc.src/gcc/config/i386/mmx.md:926: error: expected '}' before ')' token
../../llvm-gcc.src/gcc/config/i386/mmx.md:926: error: expected ',' or ';' before ')' token
../../llvm-gcc.src/gcc/config/i386/mmx.md:927: error: expected identifier or '(' before ',' token
../../llvm-gcc.src/gcc/config/i386/sse.md:3458: error: expected identifier or '(' before ',' token
...

llvm-svn: 62506
 2009-01-19 08:46:20 +00:00
Chris Lattner
f2bb4ea39c Fix PR3016, a bug which can occur do to an invalid assumption: 
we assumed a CFG structure that would be valid when all code in 
the function is reachable, but not all code is necessarily 
reachable.  Do a simple, but horrible, CFG walk to check for this
case.

llvm-svn: 62487
 2009-01-19 02:46:28 +00:00
Chris Lattner
e381d7026f reduce indentation by using 'continue', no functionality change. 
llvm-svn: 62477
 2009-01-19 02:07:32 +00:00
Chris Lattner
54f0c61d71 Fix some problems in SpeculativelyExecuteBB. Basically, 
because of dead code, a phi could use the speculated instruction
that was not in "BB2".  Make this check explicit and tighten up 
some other corners.  This fixes PR3292.  No testcase becauase this
depends entirely on visitation order of blocks and requires a 
sequence of 8 passes to repro.

llvm-svn: 62476
 2009-01-19 00:36:37 +00:00
Chris Lattner
e1c01e4e2b Make this a bit more explicit about which cases need the 
check.  No functionality change.

llvm-svn: 62474
 2009-01-18 23:22:07 +00:00
Eli Friedman
cb61afb546 Add a helper to remove a branch and DCE the condition, and use it 
consistently for deleting branches.  In addition to being slightly 
more readable, this makes SimplifyCFG a bit better 
about cleaning up after itself when it makes conditions unused.

llvm-svn: 61100
 2008-12-16 20:54:32 +00:00
Chris Lattner
f50d7f76c6 fix a bug I introduced in simplifycfg handling single entry phi 
nodes. FoldSingleEntryPHINodes deletes the PHI, so there is no
need to delete it afterward.

llvm-svn: 60653
 2008-12-07 07:22:45 +00:00
Chris Lattner
dc3f6f2c12 Factor some code into a new FoldSingleEntryPHINodes method. 
llvm-svn: 60501
 2008-12-03 19:44:02 +00:00
Chris Lattner
7eb270ed03 Rename DeleteBlockIfDead to DeleteDeadBlock and make it 
unconditionally delete the block.  All likely clients will
do the checking anyway.

llvm-svn: 60464
 2008-12-03 06:40:52 +00:00
Chris Lattner
bcc904a67c Factor some code out of SimplifyCFG, forming a new 
DeleteBlockIfDead method.

llvm-svn: 60463
 2008-12-03 06:37:44 +00:00
Chris Lattner
8e84c129ce delete ErasePossiblyDeadInstructionTree, replacing uses of it with 
RecursivelyDeleteTriviallyDeadInstructions.

llvm-svn: 60196
 2008-11-27 23:25:44 +00:00
Chris Lattner
d6204bed3d simplify this code a bit. 
llvm-svn: 60164
 2008-11-27 07:54:38 +00:00
Chris Lattner
0934c0f35b Fix PR2967 by not deleting volatile load/stores that occur before unreachable. 
I don't really see this as being needed, but there is little harm from doing
it.

llvm-svn: 58385
 2008-10-29 17:46:26 +00:00
Devang Patel
f963403b58 Nick Lewycky's patch. 
While hosting instruction check PHI node.

llvm-svn: 57025
 2008-10-03 18:57:37 +00:00
Devang Patel
4c758ea3e0 Large mechanical patch. 
s/ParamAttr/Attribute/g
s/PAList/AttrList/g
s/FnAttributeWithIndex/AttributeWithIndex/g
s/FnAttr/Attribute/g

This sets the stage 
- to implement function notes as function attributes and 
- to distinguish between function attributes and return value attributes.

This requires corresponding changes in llvm-gcc and clang.

llvm-svn: 56622
 2008-09-25 21:00:45 +00:00
Devang Patel
76b22c1420 Try to place hoisted instructions befoe icmp instruction. 
llvm-svn: 56315
 2008-09-18 22:50:42 +00:00
Devang Patel
7f9671ba37 Do not hoist instruction above branch condition. The instruction may use branch condition. 
llvm-svn: 56286
 2008-09-17 18:21:49 +00:00
Dan Gohman
8de6d22392 Use empty() instead of begin() == end(). 
llvm-svn: 54780
 2008-08-14 18:13:49 +00:00
Dan Gohman
fa1211f69b Enable first-class aggregates support. 
Remove the GetResultInst instruction. It is still accepted in LLVM assembly
and bitcode, where it is now auto-upgraded to ExtractValueInst. Also, remove
support for return instructions with multiple values. These are auto-upgraded
to use InsertValueInst instructions.

The IRBuilder still accepts multiple-value returns, and auto-upgrades them
to InsertValueInst instructions.

llvm-svn: 53941
 2008-07-23 00:34:11 +00:00
Owen Anderson
9858691f25 Reapply r53735. My last patch fixed the failures Dan observed. 
llvm-svn: 53761
 2008-07-18 17:49:43 +00:00
Dan Gohman
29c3adaae0 Revert r53735. It broke SPEC 464.h264ref. 
llvm-svn: 53757
 2008-07-18 16:44:49 +00:00
Owen Anderson
fd7102037d Use MergeBlockIntoPredecessor to simplify some code. 
llvm-svn: 53735
 2008-07-17 20:00:46 +00:00
Chris Lattner
80b03a1b49 Fix mishandling of the infinite loop case when merging two blocks. This 
fixes PR2540.

llvm-svn: 53533
 2008-07-13 22:23:11 +00:00
Chris Lattner
834ab4ec1b more refactoring. Use early exits instead of really complex logic. 
No functionality change.

llvm-svn: 53532
 2008-07-13 22:04:41 +00:00
Chris Lattner
5eed37224a improve comments. 
llvm-svn: 53531
 2008-07-13 21:55:46 +00:00
Chris Lattner
9aada1d755 factor another large hunk of code out into its own function. 
No functionality change.

llvm-svn: 53530
 2008-07-13 21:53:26 +00:00
Chris Lattner
55eaae1e0c Final bit of simplification for FoldBranchToCommonDest. 
llvm-svn: 53528
 2008-07-13 21:20:19 +00:00
Chris Lattner
1b317ea48a simplify logic a bit 
llvm-svn: 53527
 2008-07-13 21:15:11 +00:00
Chris Lattner
2e25b8f444 Refactor some code out into its own helper function, getting rid of crazy multiline 
conditionals and commenting the code better.

No functionality change.

llvm-svn: 53526
 2008-07-13 21:12:01 +00:00
Evan Cheng
5fd28b54c7 - Use O(1) check of basic block size limit. 
- Avoid speculatively execute vector ops.

llvm-svn: 52703
 2008-06-25 07:50:12 +00:00
Evan Cheng
89553cc42e Do not speculatively execute an instruction by hoisting it to its predecessor BB if any of its operands are defined but not used in BB. The transformation will prevent the operand from being sunk into the use block. 
llvm-svn: 52244
 2008-06-12 21:15:59 +00:00
Evan Cheng
933c743042 For now, avoid generating FP select instructions in order to speculatively execute integer arithmetic instructions. FP selects are more likely to be expensive (even compared to branch on fcmp). This is not a wonderful solution but I rather err on the side of conservative. 
This fixes the heapsort performance regressions.

llvm-svn: 52224
 2008-06-11 19:18:20 +00:00
Gabor Greif
945f2f7fed op_iterator-ify loops 
llvm-svn: 52191
 2008-06-10 22:03:26 +00:00
Evan Cheng
89200c9177 Speculatively execute a block when the the block is the then part of a triangle shape and it contains a single, side effect free, cheap instruction. The branch is eliminated by adding a select instruction. i.e. 
Turn                                                                                                                                                                                                       
BB:                                                                                                                                                                                                        
    %t1 = icmp                                                                                                                                                                                             
    br i1 %t1, label %BB1, label %BB2                                                                                                                                                                      
BB1:                                                                                                                                                                                                       
    %t3 = add %t2, c                                                                                                                                                                                       
    br label BB2                                                                                                                                                                                           
BB2:                                                                                                                                                                                                       
=>                                                                                                                                                                                                         
BB:                                                                                                                                                                                                        
    %t1 = icmp                                                                                                                                                                                             
    %t4 = add %t2, c                                                                                                                                                                                       
    %t3 = select i1 %t1, %t2, %t3

llvm-svn: 52073
 2008-06-07 08:52:29 +00:00
Dan Gohman
f96e1371e8 Tidy up BasicBlock::getFirstNonPHI, and change a bunch of places to 
use it instead of duplicating its functionality.

llvm-svn: 51499
 2008-05-23 21:05:58 +00:00
Matthijs Kooijman
aef2b8198b Restucture a part of the SimplifyCFG pass and include a testcase. 
The SimplifyCFG pass looks at basic blocks that contain only phi nodes,
followed by an unconditional branch. In a lot of cases, such a block (BB) can
be merged into their successor (Succ).

This merging is performed by TryToSimplifyUncondBranchFromEmptyBlock. It does
this by taking all phi nodes in the succesor block Succ and expanding them to
include the predecessors of BB. Furthermore, any phi nodes in BB are moved to
Succ and expanded to include the predecessors of Succ as well.

Before attempting this merge, CanPropagatePredecessorsForPHIs checks to see if
all phi nodes can be properly merged. All functional changes are made to
this function, only comments were updated in
TryToSimplifyUncondBranchFromEmptyBlock.

In the original code, CanPropagatePredecessorsForPHIs looks quite convoluted
and more like stack of checks added to handle different kinds of situations
than a comprehensive check. In particular the first check in the function did
some value checking for the case that BB and Succ have a common predecessor,
while the last check in the function simply rejected all cases where BB and
Succ have a common predecessor. The first check was still useful in the case
that BB did not contain any phi nodes at all, though, so it was not completely
useless.

Now, CanPropagatePredecessorsForPHIs is restructured to to look a lot more
similar to the code that actually performs the merge. Both functions now look
at the same phi nodes in about the same order.  Any conflicts (phi nodes with
different values for the same source) that could arise from merging or moving
phi nodes are detected. If no conflicts are found, the merge can happen.

Apart from only restructuring the checks, two main changes in functionality
happened.

Firstly, the old code rejected blocks with common predecessors in most cases.
The new code performs some extra checks so common predecessors can be handled
in a lot of cases. Wherever common predecessors still pose problems, the
blocks are left untouched.

Secondly, the old code rejected the merge when values (phi nodes) from BB were
used in any other place than Succ. However, it does not seem that there is any
situation that would require this check. Even more, this can be proven.

Consider that BB is a block containing of a single phi node "%a" and a branch
to Succ. Now, since the definition of %a will dominate all of its uses, BB
will dominate all blocks that use %a. Furthermore, since the branch from BB to
Succ is unconditional, Succ will also dominate all uses of %a.

Now, assume that one predecessor of Succ is not dominated by BB (and thus not
dominated by Succ). Since at least one use of %a (but in reality all of them)
is reachable from Succ, you could end up at a use of %a without passing
through it's definition in BB (by coming from X through Succ). This is a
contradiction, meaning that our original assumption is wrong. Thus, all
predecessors of Succ must also be dominated by BB (and thus also by Succ).

This means that moving the phi node %a from BB to Succ does not pose any
problems when the two blocks are merged, and any use checks are not needed.

llvm-svn: 51478
 2008-05-23 09:09:41 +00:00
Gabor Greif
e1f6e4b21d API change for {BinaryOperator|CmpInst|CastInst}::create*() --> Create. Legacy interfaces will be in place for some time. (Merge from use-diet branch.) 
llvm-svn: 51200
 2008-05-16 19:29:10 +00:00
Gabor Greif
697e94cc22 Fix a bunch of 80col violations that arose from the Create API change. Tweak makefile targets to find these better. 
llvm-svn: 51143
 2008-05-15 10:04:30 +00:00
Chris Lattner
8be72700b8 Fix PR2256, yet another miscompilation in simplifycfg of i 
multiple return values.

Bill, please pull this into Tak.

llvm-svn: 50332
 2008-04-28 00:19:07 +00:00
Nick Lewycky
4d43d3c72c Remove 'unwinds to' support from mainline. This patch undoes r47802 r47989 
r48047 r48084 r48085 r48086 r48088 r48096 r48099 r48109 and r48123.

llvm-svn: 50265
 2008-04-25 16:53:59 +00:00
Chris Lattner
86bbf338e5 Split some code out of the main SimplifyCFG loop into its own function. 
Fix said code to handle merging return instructions together correctly
when handling multiple return values.

llvm-svn: 50199
 2008-04-24 00:01:19 +00:00
Gabor Greif
e9ecc68d8f API changes for class Use size reduction, wave 1. 
Specifically, introduction of XXX::Create methods
for Users that have a potentially variable number of
Uses.

llvm-svn: 49277
 2008-04-06 20:25:17 +00:00
Dan Gohman
20af5a0fe7 Check to see if a two-entry PHI block can be simplified 
before trying to merge the block into its predecessors.
This allows two-entry-phi-return.ll to be simplified
into a single basic block.

llvm-svn: 48252
 2008-03-11 21:53:06 +00:00
Nick Lewycky
fb2c1a999a Turn unwind_to into "unwinds to". 
llvm-svn: 48123
 2008-03-10 02:20:00 +00:00
Nick Lewycky
42445be0df Firstly, having a BranchInst isn't exclusive with having an unwind_to. 
Secondly, we have to check whether the branch is actually pointing to the block
with the unwind in it. We could have gotten here because of the unwind_to alone.

llvm-svn: 48099
 2008-03-09 07:50:37 +00:00
Nick Lewycky
f3d637fa14 A BB that unwind_to an "unwind" inst is that same as one that doesn't unwind_to 
at all.

llvm-svn: 48096
 2008-03-09 07:36:38 +00:00
Nick Lewycky
5ce9b521d7 Update the inliner and simplifycfg to handle unwind_to. 
llvm-svn: 48086
 2008-03-09 05:10:13 +00:00
Anton Korobeynikov
1bfd121321 Make Transforms to be 4.3 warnings-clean 
llvm-svn: 47371
 2008-02-20 11:26:25 +00:00
Chris Lattner
6b39cb907b switch simplifycfg from using vectors for most things to smallvectors, 
this speeds it up 2.3% on eon.

llvm-svn: 47261
 2008-02-18 07:42:56 +00:00
Chris Lattner
f391883670 don't hoist FP additions into unconditional adds + selects. This 
could theoretically introduce a trap, but is also a performance issue.
This speeds up ptrdist/ks by 8%.

llvm-svn: 45533
 2008-01-03 07:25:26 +00:00
Chris Lattner
f3ebc3f3d2 Remove attribution from file headers, per discussion on llvmdev. 
llvm-svn: 45418
 2007-12-29 20:36:04 +00:00
Devang Patel
7a2c66b11e If succ has succ itself as one of the predecessors then do 
not merge current bb and succ even if bb's terminator is
unconditional branch to succ.

llvm-svn: 45305
 2007-12-22 01:32:53 +00:00
Duncan Sands
ad0ea2d430 Fix PR1146: parameter attributes are longer part of 
the function type, instead they belong to functions
and function calls.  This is an updated and slightly
corrected version of Reid Spencer's original patch.
The only known problem is that auto-upgrading of
bitcode files doesn't seem to work properly (see
test/Bitcode/AutoUpgradeIntrinsics.ll).  Hopefully
a bitcode guru (who might that be? :) ) will fix it.

llvm-svn: 44359
 2007-11-27 13:23:08 +00:00
David Greene
17a5dfe6f7 New CallInst interface to address GLIBCXX_DEBUG errors caused by 
indexing an empty std::vector.

Updates to all clients.

llvm-svn: 40660
 2007-08-01 03:43:44 +00:00
Dan Gohman
30978078bf Minor comment cleanups. 
llvm-svn: 37321
 2007-05-24 14:36:04 +00:00
Chris Lattner
77a3edcb92 remove use of Instruction::getNext 
llvm-svn: 36199
 2007-04-17 17:47:54 +00:00
Chris Lattner
b7b75145f1 reduce use of std::set 
llvm-svn: 35576
 2007-04-02 01:44:59 +00:00
Dan Gohman
dcb291faa4 Change uses of Function::front to Function::getEntryBlock for readability. 
llvm-svn: 35265
 2007-03-22 16:38:57 +00:00
Reid Spencer
bb38d79ad6 Make sorting of ConstantInt be APInt clean through use of ult function. 
llvm-svn: 34853
 2007-03-02 23:01:14 +00:00
Chris Lattner
a06a8fd2d7 Eliminate use of ctors that take vectors. 
llvm-svn: 34219
 2007-02-13 02:10:56 +00:00