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7362 Commits

Author SHA1 Message Date
Bill Wendling
5e3605552e Whitespace fixes. No functionality change. 
llvm-svn: 122110
 2010-12-17 23:27:41 +00:00
Nate Begeman
7aa18bf46a Add vector versions of some existing scalar transforms to aid codegen in matching psign & pblend operations to the IR produced by clang/gcc for their C idioms. 
llvm-svn: 122105
 2010-12-17 23:12:19 +00:00
Owen Anderson
1294ea7d53 Reapply r121905 (automatic synthesis of @llvm.sadd.with.overflow) with a fix for a bug that manifested itself 
on the DragonEgg self-host bot.  Unfortunately, the testcase is pretty messy and doesn't reduce well due to
interactions with other parts of InstCombine.

llvm-svn: 122072
 2010-12-17 18:08:00 +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
Dan Gohman
93dc2b808f Revert r64460. strtol and friends cannot be marked readonly, even with 
a null endptr argument, because they may write to errno.

This fixes a seflhost miscompile observed on Linux targets when TBAA
was enabled.

llvm-svn: 122014
 2010-12-17 01:09:43 +00:00
Frits van Bommel
9bbe849fc3 Fix a bug in the loop in JumpThreading::ProcessThreadableEdges() where it could falsely produce a MultipleDestSentinel value if the first predecessor ended with an 'indirectbr'. If that happened, it caused an unnecessary FindMostPopularDest() call. 
This wasn't a correctness problem, but it broke the fast path for single-predecessor blocks.

llvm-svn: 121966
 2010-12-16 12:16:00 +00:00
Duncan Sands
8d1ab6f6e1 Speculatively revert commit 121905 since it looks like it might have broken the 
dragonegg self-host buildbot.  Original commit message:

Add an InstCombine transform to recognize instances of manual overflow-safe addition
(performing the addition in a wider type and explicitly checking for overflow), and
fold them down to intrinsics.  This currently only supports signed-addition, but could
be generalized if someone works out the magic constant formulas for other operations.

llvm-svn: 121965
 2010-12-16 09:40:54 +00:00
Dan Gohman
e1a17a3473 Make memcpyopt TBAA-aware. 
llvm-svn: 121944
 2010-12-16 02:51:19 +00:00
Dan Gohman
4467aa5294 Preserve TBAA tags when doing load PRE. 
llvm-svn: 121921
 2010-12-15 23:53:55 +00:00
Owen Anderson
1cf8881299 Add an InstCombine transform to recognize instances of manual overflow-safe addition 
(performing the addition in a wider type and explicitly checking for overflow), and
fold them down to intrinsics.  This currently only supports signed-addition, but could
be generalized if someone works out the magic constant formulas for other operations.

Fixes <rdar://problem/8558713>.

llvm-svn: 121905
 2010-12-15 22:32:38 +00:00
Dan Gohman
a4fcd2418d Move Value::getUnderlyingObject to be a standalone 
function so that it can live in Analysis instead of
VMCore.

llvm-svn: 121885
 2010-12-15 20:02:24 +00:00
Duncan Sands
0a2c416894 Move Sub simplifications and additional Add simplifications out of 
instcombine and into InstructionSimplify.

llvm-svn: 121861
 2010-12-15 14:07:39 +00:00
Frits van Bommel
3d1803495e Teach jump threading to "look through" a select when the branch direction of a terminator depends on it. 
When it sees a promising select it now tries to figure out whether the condition of the select is known in any of the predecessors and if so it maps the operands appropriately.

llvm-svn: 121859
 2010-12-15 09:51:20 +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
Owen Anderson
35609d97ae Fix PR8790, another instance where unreachable code can cause instruction simplification to fail, 
this case involve a select that simplifies to itself.

llvm-svn: 121817
 2010-12-15 00:55:35 +00:00
Owen Anderson
15c85c916f Cleanup trailing whitespace. 
llvm-svn: 121816
 2010-12-15 00:52:44 +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
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