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475 Commits

Author SHA1 Message Date
Devang Patel
15ad6761da Set up IRBuilder for use during simplification. 
llvm-svn: 131545
 2011-05-18 18:01:27 +00:00
Devang Patel
b849cd511b Preseve line numbers while simplifying CFG. 
llvm-svn: 131508
 2011-05-17 23:29:05 +00:00
Benjamin Kramer
d96205c4e5 SimplifyCFG: Use ComputeMaskedBits to prune dead cases from switch instructions. 
llvm-svn: 131345
 2011-05-14 15:57:25 +00:00
Peter Collingbourne
616044acd5 SimplifyCFG: Expose phi node folding cost threshold as command line parameter 
llvm-svn: 130528
 2011-04-29 18:47:38 +00:00
Peter Collingbourne
e3511e15e0 SimplifyCFG: Add CostRemaining parameter to DominatesMergePoint 
llvm-svn: 130527
 2011-04-29 18:47:31 +00:00
Peter Collingbourne
61f6602acd SimplifyCFG: Add Trunc, ZExt and SExt to the list of cheap instructions for phi node folding 
llvm-svn: 130526
 2011-04-29 18:47:25 +00:00
Chris Lattner
fba5cdfce1 rework FoldBranchToCommonDest to exit earlier when there is a bonus 
instruction around, reducing work.

Greatly simplify handling of debug instructions.  There is no need to
build up a vector of them and then move them into the one predecessor
if we're processing a block.  Instead just rescan the block and *copy*
them into the pred.  If a block gets merged into multiple preds, this
will retain more debug info.

llvm-svn: 129502
 2011-04-14 02:44:53 +00:00
Chris Lattner
7d4cdae564 comment cleanup, use moveBefore instead of removeFromParent+insertBefore. 
llvm-svn: 129319
 2011-04-11 23:24:57 +00:00
Devang Patel
bc3d8b212f Do not let debug info interfer with branch folding. 
llvm-svn: 129114
 2011-04-07 23:11:25 +00:00
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