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1998 Commits

Author SHA1 Message Date
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 f130661688 fix yet anohter broken line 
llvm-svn: 121750
 2010-12-14 06:09:07 +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
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 cb570f87e5 fix a bug in r121680 that upset the various buildbots. 
llvm-svn: 121687
 2010-12-13 05:34:18 +00:00
Chris Lattner bc9e6d9dbe make these tests a bit less fragile 
llvm-svn: 121682
 2010-12-13 05:10:30 +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 a737721d14 merge two tests 
llvm-svn: 121679
 2010-12-13 04:45:56 +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 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
Benjamin Kramer c4169cebe3 Generalize the and-icmp-select instcombine further by allowing selects of the form 
(x & 2^n) ? 2^m+C : C

we can offset both arms by C to get the "(x & 2^n) ? 2^m : 0" form, optimize the
select to a shift and apply the offset afterwards.

llvm-svn: 121609
 2010-12-11 10:49:22 +00:00
Benjamin Kramer c8b035d006 Factor the (x & 2^n) ? 2^m : 0 instcombine into its own method and generalize it 
to catch cases where n != m with a shift.

llvm-svn: 121608
 2010-12-11 09:42:59 +00:00
Chris Lattner bc4457e317 enhance memcpyopt to zap memcpy's that have the same src/dst. 
llvm-svn: 121362
 2010-12-09 07:45:45 +00:00
Chris Lattner fd51c52ef6 fix PR8753, eliminating a case where we'd infinitely make a 
substitution because it doesn't actually change the IR.  Patch by
Jakub Staszak!

llvm-svn: 121361
 2010-12-09 07:39:50 +00:00
Dan Gohman a32986e899 Really check that the bits that will become zero are actually already zero 
before eliminating the operation that zeros them. This fixes rdar://8739316.

llvm-svn: 121353
 2010-12-09 02:52:17 +00:00
Chris Lattner 0d71c4f564 reapply r121100 with a tweak to constant fold ConstExprs with TargetData 
(if available) as we go so that we get simple constantexprs not insane ones.
This fixes the failure of clang/test/CodeGenCXX/virtual-base-ctor.cpp
that the previous iteration of this patch had.

llvm-svn: 121111
 2010-12-07 04:33:29 +00:00
Eric Christopher f10dcfb9fb Temporarily revert r121100 as it's causing clang to fail 
CodeGenCXX/virtual-base-ctor.cpp.

llvm-svn: 121102
 2010-12-07 02:41:11 +00:00
Chris Lattner 287f4366c1 fix PR8710 - teach global opt that some constantexprs are too complex to 
put in a global variable's initializer.

llvm-svn: 121100
 2010-12-07 01:59:32 +00:00
Frits van Bommel d9df6eaa9c Implement jump threading of 'indirectbr' by keeping track of whether we're looking for ConstantInt*s or BlockAddress*s. 
llvm-svn: 121066
 2010-12-06 23:36:56 +00:00
Chris Lattner 94fbdf3814 Fix PR8728, a miscompilation I recently introduced. When optimizing 
memcpy's like:
  memcpy(A, B)
  memcpy(A, C)

we cannot delete the first memcpy as dead if A and C might be aliases.
If so, we actually get:

  memcpy(A, B)
  memcpy(A, A)

which is not correct to transform into:

  memcpy(A, A)

This patch was heavily influenced by Jakub Staszak's patch in PR8728, thanks
Jakub!

llvm-svn: 120974
 2010-12-06 01:48:06 +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
Chris Lattner 1c577b54b0 fix a bozo bug I introduced in r119930, causing a miscompile of 
20040709-1.c from the gcc testsuite.  I was using the size of a
pointer instead of the pointee.  This fixes rdar://8713376

llvm-svn: 120519
 2010-12-01 01:24:55 +00:00
Chris Lattner 903add84d9 Enhance DSE to handle the variable index case in PR8657. 
llvm-svn: 120498
 2010-11-30 23:43:23 +00:00
Chris Lattner c0f3379ae0 teach DSE to use GetPointerBaseWithConstantOffset to analyze 
may-aliasing stores that partially overlap with different base
pointers.  This implements PR6043 and the non-variable part of
PR8657

llvm-svn: 120485
 2010-11-30 23:05:20 +00:00
Chris Lattner b63ba73b1b enhance isRemovable to refuse to delete volatile mem transfers 
now that DSE hacks on them.  This fixes a regression I introduced,
by generalizing DSE to hack on transfers.

llvm-svn: 120445
 2010-11-30 19:12:10 +00:00
Chris Lattner 58b779e9c2 Rewrite the main DSE loop to be written in terms of reasoning 
about pairs of AA::Location's instead of looking for MemDep's
"Def" predicate.  This is more powerful and general, handling
memset/memcpy/store all uniformly, and implementing PR8701 and
probably obsoleting parts of memcpyoptimizer.

This also fixes an obscure bug with init.trampoline and i8
stores, but I'm not surprised it hasn't been hit yet.  Enhancing
init.trampoline to carry the size that it stores would allow
DSE to be much more aggressive about optimizing them.

llvm-svn: 120406
 2010-11-30 07:23:21 +00:00
Anders Carlsson e3ea1cba79 Add a puts optimization that converts puts() to putchar('\n'). 
llvm-svn: 120398
 2010-11-30 06:19:18 +00:00
Anders Carlsson 77e9892afd Fix a typo. 
llvm-svn: 120394
 2010-11-30 06:03:55 +00:00
Anders Carlsson 631d06bbce Rename this test to FPuts.ll since it actually tests fputs. 
llvm-svn: 120393
 2010-11-30 05:59:26 +00:00
Chris Lattner 6c7f64e0bc remove a use of llvm-dis 
llvm-svn: 120383
 2010-11-30 02:04:15 +00:00
Chris Lattner c2e3445273 merge one more away 
llvm-svn: 120375
 2010-11-30 01:06:43 +00:00
Chris Lattner 7578d0df51 I already merged partial-overwrite.ll -> PartialStore.ll 
Merge context-sensitive.ll -> simple.ll and upgrade it.

llvm-svn: 120374
 2010-11-30 01:05:07 +00:00
Chris Lattner 43e3a98675 clean up DSE tests, removing some poorly reduced and useless old test, 
merging more into other larger .ll files, filecheckizing along the way.

llvm-svn: 120373
 2010-11-30 01:00:34 +00:00
Chris Lattner 90c4947df7 enhance basicaa to return "Mod" for a memcpy call when the 
queried location doesn't overlap the source, and add a testcase.

llvm-svn: 120370
 2010-11-30 00:43:16 +00:00
Chris Lattner 9a146372b5 Teach basicaa that memset's modref set is at worst "mod" and never 
contains "ref".

Enhance DSE to use a modref query instead of a store-specific hack
to generalize the "ignore may-alias stores" optimization to handle
memset and memcpy.

llvm-svn: 120368
 2010-11-30 00:28:45 +00:00
Chris Lattner c3c754f750 my previous patch would cause us to start deleting some volatile 
stores, fix and add a testcase.

llvm-svn: 120363
 2010-11-30 00:12:39 +00:00
Benjamin Kramer e6840ef4b3 Fix some broken CHECK lines. 
llvm-svn: 120332
 2010-11-29 22:34:55 +00:00
Chris Lattner 2e8793482c fix PR8677, patch by Jakub Staszak! 
llvm-svn: 120325
 2010-11-29 21:59:31 +00:00
Frits van Bommel 28218aa8f1 Transform (extractvalue (load P), ...) to (load (gep P, 0, ...)) if the load has no other uses, shrinking the load. 
llvm-svn: 120323
 2010-11-29 21:56:20 +00:00
Frits van Bommel 40a80ac963 Update this test to keep testing the -instcombine transform it's supposed to be testing instead of triggering the improved constant folding for insertvalue and extractvalue. 
llvm-svn: 120319
 2010-11-29 20:55:40 +00:00
Frits van Bommel a98214de10 Teach ConstantFoldInstruction() how to fold insertvalue and extractvalue. 
llvm-svn: 120316
 2010-11-29 20:36:52 +00:00
Nick Lewycky b8de00ee07 Treat a call of function pointer like a load of the pointer when considering 
whether the pointer can be replaced with the global variable it is a copy of.
Fixes PR8680.

llvm-svn: 120126
 2010-11-24 22:04:20 +00:00
Benjamin Kramer 94a622af4c The srem -> urem transform is not safe for any divisor that's not a power of two. 
E.g. -5 % 5 is 0 with srem and 1 with urem.

Also addresses Frits van Bommel's comments.

llvm-svn: 120049
 2010-11-23 20:33:57 +00:00
Benjamin Kramer b5afa65b0a InstCombine: Reduce "X shift (A srem B)" to "X shift (A urem B)" iff B is positive. 
This allows to transform the rem in "1 << ((int)x % 8);" to an and.

llvm-svn: 120028
 2010-11-23 18:52:42 +00:00