329 Commits

Author SHA1 Message Date
Devang Patel
40690a2df4 Use IRBuilder while simplifying unwind.
llvm-svn: 131561
2011-05-18 20:01:18 +00:00
Devang Patel
f0b8a243b9 Use IRBuilder while simplifying terminator.
llvm-svn: 131552
2011-05-18 18:43:31 +00:00
Devang Patel
faedd704bb Use IRBuilder while simplifying unconditional branch.
llvm-svn: 131551
2011-05-18 18:28:48 +00:00
Devang Patel
9249a85cdc Use IRBuilder while folding two entry PHINode.
llvm-svn: 131548
2011-05-18 18:16:44 +00:00
Devang Patel
6eb1a7bd09 Set up IRBuilder for use during simplification.
llvm-svn: 131545
2011-05-18 18:01:27 +00:00
Devang Patel
b75e746499 Preseve line numbers while simplifying CFG.
llvm-svn: 131508
2011-05-17 23:29:05 +00:00
Benjamin Kramer
5943d0a3ee SimplifyCFG: Use ComputeMaskedBits to prune dead cases from switch instructions.
llvm-svn: 131345
2011-05-14 15:57:25 +00:00
Peter Collingbourne
d78bf257ad SimplifyCFG: Expose phi node folding cost threshold as command line parameter
llvm-svn: 130528
2011-04-29 18:47:38 +00:00
Peter Collingbourne
0994e869f9 SimplifyCFG: Add CostRemaining parameter to DominatesMergePoint
llvm-svn: 130527
2011-04-29 18:47:31 +00:00
Peter Collingbourne
06646aa091 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
88e2acc24c 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
2871dd44cb comment cleanup, use moveBefore instead of removeFromParent+insertBefore.
llvm-svn: 129319
2011-04-11 23:24:57 +00:00
Devang Patel
47e1db49c9 Do not let debug info interfer with branch folding.
llvm-svn: 129114
2011-04-07 23:11:25 +00:00
Devang Patel
17670a995c 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
bb234bb5dd Simplify. isIdenticalToWhenDefined() checks opcode.
llvm-svn: 129041
2011-04-07 00:30:15 +00:00
Devang Patel
12a95842b2 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
53632b7c03 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
dc5a008237 (Almost) always call reserveOperandSpace() on newly created PHINodes.
llvm-svn: 128535
2011-03-30 11:19:20 +00:00
Eli Friedman
c0bfbd0610 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
d1e9ff0d6c 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
4a2b658705 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
39a5d8596c 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
44b43a85db SimplifyCFG: GEPs with just one non-constant index are also cheap.
llvm-svn: 126452
2011-02-24 23:26:09 +00:00
Benjamin Kramer
b5996b08b7 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
04249128ab 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
75785ec972 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
b739613711 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
4af5487b74 Re-apply r124518 with fix. Watch out for invalidated iterator.
llvm-svn: 124526
2011-01-29 04:46:23 +00:00
Evan Cheng
1f943b9b13 Revert r124518. It broke Linux self-host.
llvm-svn: 124522
2011-01-29 02:43:04 +00:00
Evan Cheng
a1e4cb5f09 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
5b6c72e549 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
7031f450b3 - 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
f5bd48972a 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
25d76d1e53 simplify this a bit.
llvm-svn: 122156
2010-12-18 20:22:49 +00:00
Benjamin Kramer
39b30b18fa 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
e92f8121d4 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
1499119975 make qsort predicate more conformant by returning 0 for equal values.
llvm-svn: 121838
2010-12-15 04:52:41 +00:00
Chris Lattner
c1aaf52608 - 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
22d4dc5a4d 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
362f9a82c0 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
c2e42269ae 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
8e4194276b 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
811462b2f4 use SimplifyInstruction instead of reimplementing part of it.
llvm-svn: 121757
2010-12-14 07:20:29 +00:00
Chris Lattner
e2400eb801 simplify GetIfCondition by using getSinglePredecessor.
llvm-svn: 121756
2010-12-14 07:15:21 +00:00
Chris Lattner
8ea88e66dd use AddPredecessorToBlock in 3 places instead of a manual loop.
llvm-svn: 121755
2010-12-14 07:09:42 +00:00
Chris Lattner
a87ac36a54 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
d9436ab7d7 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
093b5b256d 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
5536134dc4 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
dcba81d96f 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