Commit Graph

1549 Commits

Author SHA1 Message Date
Duncan Sands
697de77339 Speed up instsimplify by about 10-15% by not bothering to retry
InstructionSimplify on instructions that didn't change since the
last time round the loop.

llvm-svn: 122745
2011-01-03 10:50:04 +00:00
Chris Lattner
bf0aa927cc split dom frontier handling stuff out to its own DominanceFrontier header,
so that Dominators.h is *just* domtree.  Also prune #includes a bit.

llvm-svn: 122714
2011-01-02 22:09:33 +00:00
Duncan Sands
64f1c0dcda Fix PR8702 by not having LoopSimplify claim to preserve LCSSA form. As described
in the PR, the pass could break LCSSA form when inserting preheaders.  It probably
would be easy enough to fix this, but since currently we always go into LCSSA form
after running this pass, doing so is not urgent.

llvm-svn: 122695
2011-01-02 13:38:21 +00:00
Duncan Sands
2c440fa403 Simplify this pass by using a depth-first iterator to ensure that all
operands are visited before the instructions themselves.

llvm-svn: 122647
2010-12-31 17:49:05 +00:00
Duncan Sands
6cc7126ed9 Zap dead instructions harder.
llvm-svn: 122645
2010-12-31 16:17:54 +00:00
Benjamin Kramer
570dd787a6 Make a bunch of symbols internal.
llvm-svn: 122642
2010-12-30 22:34:44 +00:00
Benjamin Kramer
84bd73c527 BuildLibCalls: Nuke EmitMemCpy, EmitMemMove and EmitMemSet. They are dead and superseded by IRBuilder.
llvm-svn: 122576
2010-12-27 00:25:32 +00:00
Chris Lattner
d729d0dcdb don't lose TD info
llvm-svn: 122556
2010-12-25 20:52:04 +00:00
Chris Lattner
20fca48341 switch the inliner alignment enforcement stuff to use the
getOrEnforceKnownAlignment function, which simplifies the code
and makes it stronger.

llvm-svn: 122555
2010-12-25 20:42:38 +00:00
Chris Lattner
6fcd32e7d7 Move getOrEnforceKnownAlignment out of instcombine into Transforms/Utils.
llvm-svn: 122554
2010-12-25 20:37:57 +00:00
Jeffrey Yasskin
9b43f33620 Change all self assignments X=X to (void)X, so that we can turn on a
new gcc warning that complains on self-assignments and
self-initializations.

llvm-svn: 122458
2010-12-23 00:58:24 +00:00
Duncan Sands
3b8af41a3e Visit instructions deterministically. Use a FIFO so as to approximately
visit instructions before their uses, since InstructionSimplify does a
better job in that case.  All this prompted by Frits van Bommel.

llvm-svn: 122343
2010-12-21 17:08:55 +00:00
Duncan Sands
e7cbb64ec0 If an instruction simplifies, try again to simplify any uses of it. This is
not very important since the pass is only used for testing, but it does make
it more realistic.  Suggested by Frits van Bommel.

llvm-svn: 122336
2010-12-21 16:12:03 +00:00
Duncan Sands
eaff500c7b Oops, forgot to add the pass itself!
llvm-svn: 122265
2010-12-20 21:07:42 +00:00
Duncan Sands
a436cbe4bf Add a new convenience pass for testing InstructionSimplify. Previously
it could only be tested indirectly, via instcombine, gvn or some other
pass that makes use of InstructionSimplify, which means that testcases
had to be carefully contrived to dance around any other transformations
that that pass did.

llvm-svn: 122264
2010-12-20 20:54:37 +00:00
Chris Lattner
0f11495289 when eliding a byval copy due to inlining a readonly function, we have
to make sure that the reused alloca has sufficient alignment.

llvm-svn: 122236
2010-12-20 08:10:40 +00:00
Chris Lattner
0099744506 pull byval processing out to its own helper function.
llvm-svn: 122235
2010-12-20 07:57:41 +00:00
Chris Lattner
7394680a00 fix PR8769, a miscompilation by inliner when inlining a function with a byval
argument.  The generated alloca has to have at least the alignment of the
byval, if not, the client may be making assumptions that the new alloca won't
satisfy.

llvm-svn: 122234
2010-12-20 07:45:28 +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
afd2a8cfbb remove the dead (and terrible) llvm::RemoveSuccessor function.
llvm-svn: 121753
2010-12-14 06:51:55 +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