Commit Graph

68 Commits

Author SHA1 Message Date
Chris Lattner 445d8c6b50 fold comparisons of gep'd alloca points with null to false,
implementing PR12013.  We now compile the testcase to:

__Z4testv:                              ## @_Z4testv
## BB#0:                                ## %_ZN4llvm15SmallVectorImplIiE9push_backERKi.exit
	pushq	%rbx
	subq	$64, %rsp
	leaq	32(%rsp), %rbx
	movq	%rbx, (%rsp)
	leaq	64(%rsp), %rax
	movq	%rax, 16(%rsp)
	movl	$1, 32(%rsp)
	leaq	36(%rsp), %rax
	movq	%rax, 8(%rsp)
	leaq	(%rsp), %rdi
	callq	__Z1gRN4llvm11SmallVectorIiLj8EEE
	movq	(%rsp), %rdi
	cmpq	%rbx, %rdi
	je	LBB0_2
## BB#1:
	callq	_free
LBB0_2:                                 ## %_ZN4llvm11SmallVectorIiLj8EED1Ev.exit
	addq	$64, %rsp
	popq	%rbx
	ret

instead of:

__Z4testv:                              ## @_Z4testv
## BB#0:
	pushq	%rbx
	subq	$64, %rsp
	xorl	%eax, %eax
	leaq	(%rsp), %rbx
	addq	$32, %rbx
	movq	%rbx, (%rsp)
	movq	%rbx, 8(%rsp)
	leaq	64(%rsp), %rcx
	movq	%rcx, 16(%rsp)
	je	LBB0_2
## BB#1:
	movl	$1, 32(%rsp)
	movq	%rbx, %rax
LBB0_2:                                 ## %_ZN4llvm15SmallVectorImplIiE9push_backERKi.exit
	addq	$4, %rax
	movq	%rax, 8(%rsp)
	leaq	(%rsp), %rdi
	callq	__Z1gRN4llvm11SmallVectorIiLj8EEE
	movq	(%rsp), %rdi
	cmpq	%rbx, %rdi
	je	LBB0_4
## BB#3:
	callq	_free
LBB0_4:                                 ## %_ZN4llvm11SmallVectorIiLj8EED1Ev.exit
	addq	$64, %rsp
	popq	%rbx
	ret

This doesn't shrink clang noticably though.

llvm-svn: 150944
2012-02-20 00:42:49 +00:00
Eli Friedman 952d1f9f40 Fix a rather nasty regression from r150690: LHS != RHS does not imply LHS->stripPointerCasts() != RHS->stripPointerCasts().
llvm-svn: 150863
2012-02-18 03:29:25 +00:00
Benjamin Kramer ea51f62e4b InstSimplify: Ignore pointer casts when constant folding compares between pointers.
llvm-svn: 150690
2012-02-16 13:49:39 +00:00
Eli Bendersky 924f9a671d Replace all instances of dg.exp file with lit.local.cfg, since all tests are run with LIT now and now Dejagnu. dg.exp is no longer needed.
Patch reviewed by Daniel Dunbar. It will be followed by additional cleanup patches.

llvm-svn: 150664
2012-02-16 06:28:33 +00:00
Duncan Sands 26641d7c02 Fix PR11948: the result type of an icmp may be a vector of boolean -
don't assume it is a boolean.

llvm-svn: 150247
2012-02-10 14:31:24 +00:00
Duncan Sands bf48ac622a Revert commit 149912 (lattner) and add a testcase that shows the problem (which
is that patterns no longer match for vectors of booleans, because you only get
ConstantDataVector when the vector element type is i8, i16, etc, not when it is
i1).  Original commit message:
Remove some dead code and tidy things up now that vectors use ConstantDataVector
instead of always using ConstantVector.

llvm-svn: 150246
2012-02-10 14:26:42 +00:00
Nadav Rotem 3924cb0267 Add support for vectors of pointers.
llvm-svn: 145801
2011-12-05 06:29:09 +00:00
Duncan Sands 81a2af12d6 Fix a crash in which a multiplication was being reported as being both negative
and positive: positive, because it could be directly computed to be positive;
negative, because the nsw flags means it is either negative or undefined (the
multiplication always overflowed).

llvm-svn: 145104
2011-11-23 16:26:47 +00:00
Eli Friedman 0bae8b2cfb Fix code to match comment. Fixes PR11340, a regression from r143209.
llvm-svn: 144121
2011-11-08 21:08:02 +00:00
Dan Gohman ce3d6248b2 Add tests for existing InstSimplify features.
llvm-svn: 143721
2011-11-04 18:39:16 +00:00
Dan Gohman 85977e6ab4 Teach instsimplify to simplify calls to undef.
llvm-svn: 143719
2011-11-04 18:32:42 +00:00
Duncan Sands 3d5692a475 Reapply commit 143214 with a fix: m_ICmp doesn't match conditions
with the given predicate, it matches any condition and returns the
predicate - d'oh!  Original commit message:
The expression icmp eq (select (icmp eq x, 0), 1, x), 0 folds to false.
Spotted by my super-optimizer in 186.crafty and 450.soplex.  We really
need a proper infrastructure for handling generalizations of this kind
of thing (which occur a lot), however this case is so simple that I decided
to go ahead and implement it directly.

llvm-svn: 143318
2011-10-30 19:56:36 +00:00
Eli Friedman 3af3c046a9 Revert r143214; it's breaking a bunch of stuff.
llvm-svn: 143265
2011-10-29 00:56:07 +00:00
Duncan Sands 280bc553b3 The expression icmp eq (select (icmp eq x, 0), 1, x), 0 folds to false.
Spotted by my super-optimizer in 186.crafty and 450.soplex.  We really
need a proper infrastructure for handling generalizations of this kind
of thing (which occur a lot), however this case is so simple that I decided
to go ahead and implement it directly.

llvm-svn: 143214
2011-10-28 19:01:20 +00:00
Duncan Sands 985ba6386d A shift of a power of two is a power of two or zero.
For completeness - not spotted in the wild.

llvm-svn: 143211
2011-10-28 18:30:05 +00:00
Duncan Sands 92af0a8a7f Fold icmp ugt (udiv X, Y), X to false. Spotted by my super-optimizer
in 186.crafty.

llvm-svn: 143209
2011-10-28 18:17:44 +00:00
Duncan Sands 7cb61e5a0e Reapply commit 143028 with a fix: the problem was casting a ConstantExpr Mul
using BinaryOperator (which only works for instructions) when it should have
been a cast to OverflowingBinaryOperator (which also works for constants).
While there, correct a few other dubious looking uses of BinaryOperator.
Thanks to Chad Rosier for the testcase.  Original commit message:
My super-optimizer noticed that we weren't folding this expression to
true: (x *nsw x) sgt 0, where x = (y | 1).  This occurs in 464.h264ref.

llvm-svn: 143125
2011-10-27 19:16:21 +00:00
Bob Wilson 1455ce27e4 Revert Duncan's r143028 expression folding which appears to be the culprit
behind a compile failure on 483.xalancbmk.

llvm-svn: 143102
2011-10-27 15:47:25 +00:00
Duncan Sands ba286d7c73 The maximum power of 2 dividing a power of 2 is itself. This occurs
in 403.gcc and was spotted by my super-optimizer.

llvm-svn: 143054
2011-10-26 20:55:21 +00:00
Duncan Sands 1d2bb9882d My super-optimizer noticed that we weren't folding this expression to
true: (x *nsw x) sgt 0, where x = (y | 1).  This occurs in 464.h264ref.

llvm-svn: 143028
2011-10-26 15:31:51 +00:00
Benjamin Kramer 4b79c21ef2 InstSimplify: Don't try to replace an extractvalue/insertvalue pair with the original value if types don't match.
Fixes clang selfhost.

llvm-svn: 139120
2011-09-05 18:16:19 +00:00
Duncan Sands fd26a954a8 Add some simple insertvalue simplifications, for the purpose of cleaning
up do-nothing exception handling code produced by dragonegg.

llvm-svn: 139113
2011-09-05 06:52:48 +00:00
Nick Lewycky 56e99c7933 Remove bogus test: for all possible inputs of %X, the 'sub nsw' is guaranteed
to perform a signed wrap. Don't rely on any particular handling of that case.

llvm-svn: 135471
2011-07-19 08:22:57 +00:00
Dan Gohman 54664ed714 Improve constant folding of undef for cmp and select operators.
llvm-svn: 134223
2011-07-01 01:03:43 +00:00
Dan Gohman ca8d9e1341 Improve constant folding of undef for binary operators.
llvm-svn: 134221
2011-07-01 00:42:17 +00:00
Duncan Sands af32728a57 The comparision "max(x,y)==x" is equivalent to "x>=y". Since the max is
often expressed as "x >= y ? x : y", there is a good chance we can extract
the existing "x >= y" from it and use that as a replacement for "max(x,y)==x".

llvm-svn: 131049
2011-05-07 16:56:49 +00:00
Duncan Sands a228785526 Add variations on: max(x,y) >= min(x,z) folds to true. This isn't that common,
but according to my super-optimizer there are only two missed simplifications
of -instsimplify kind when compiling bzip2, and this is one of them.  It amuses
me to have bzip2 be perfectly optimized as far as instsimplify goes!

llvm-svn: 130840
2011-05-04 16:05:05 +00:00
Duncan Sands 0a9c1246d7 Implement some basic simplifications involving min/max, for example
max(a,b) >= a -> true.  According to my super-optimizer, these are
by far the most common simplifications (of the -instsimplify kind)
that occur in the testsuite and aren't caught by -std-compile-opts.

llvm-svn: 130780
2011-05-03 19:53:10 +00:00
Duncan Sands a3e3699c88 Move some rem transforms out of instcombine and into instsimplify.
This automagically provides a transform noticed by my super-optimizer
as occurring quite often: "rem x, (select cond, x, 1)" -> 0.

llvm-svn: 130694
2011-05-02 16:27:02 +00:00
Benjamin Kramer 5acc751b6f Teach ComputeMaskedBits about sub nsw.
llvm-svn: 127548
2011-03-12 17:18:11 +00:00
Nick Lewycky cc79973856 Teach ComputeMaskedBits about nsw on add. I don't think there's anything we can
do with nuw here, but sub and mul should be given similar treatment.
Fixes PR9343 #15!

llvm-svn: 127463
2011-03-11 09:00:19 +00:00
Benjamin Kramer 1885d21700 Fix mistyped CHECK lines.
llvm-svn: 127366
2011-03-09 22:07:31 +00:00
Nick Lewycky 980104d1d6 Add another micro-optimization. Apologies for the lack of refactoring, but I
gave up when I realized I couldn't come up with a good name for what the
refactored function would be, to describe what it does.

This is PR9343 test12, which is test3 with arguments reordered. Whoops!

llvm-svn: 127318
2011-03-09 06:26:03 +00:00
Nick Lewycky 9719a719c7 Thread comparisons over udiv/sdiv/ashr/lshr exact and lshr nuw/nsw whenever
possible. This goes into instcombine and instsimplify because instsimplify
doesn't need to check hasOneUse since it returns (almost exclusively) constants.

This fixes PR9343 #4 #5 and #8!

llvm-svn: 127064
2011-03-05 05:19:11 +00:00
Nick Lewycky 41c529bd09 Revert broken srem logic from r126991.
llvm-svn: 127021
2011-03-04 19:26:08 +00:00
Nick Lewycky 8e3a79da9f Fold "icmp pred (srem X, Y), Y" like we do for urem. Handle signed comparisons
in the urem case, though not the other way around. This is enough to get #3 from
PR9343!

llvm-svn: 126991
2011-03-04 10:06:52 +00:00
Nick Lewycky 3cec6f5563 Teach instruction simplify to use constant ranges to solve problems of the form
"icmp pred %X, CI" and a number of examples where "%X = binop %Y, CI2".

Some of these cases (div and rem) used to make it through opt -O2, but the
others are probably now making code elsewhere redundant (probably instcombine).

llvm-svn: 126988
2011-03-04 07:00:57 +00:00
Nick Lewycky c9d20067cd Optimize "icmp pred (urem X, Y), Y" --> true/false depending on pred. There's
more work to do here, "icmp ult (urem X, 10), 11" doesn't optimize away yet.
Fixes example 3 from PR9343!

llvm-svn: 126741
2011-03-01 08:15:50 +00:00
Duncan Sands d114ab331c Teach instsimplify that X+Y>=X+Z is the same as Y>=Z if neither side overflows,
plus some variations of this.  According to my auto-simplifier this occurs a lot
but usually in combination with max/min idioms.  Because max/min aren't handled
yet this unfortunately doesn't have much effect in the testsuite.

llvm-svn: 125462
2011-02-13 17:15:40 +00:00
Chris Lattner 9e4aa0259f Teach instsimplify some tricks about exact/nuw/nsw shifts.
improve interfaces to instsimplify to take this info.

llvm-svn: 125196
2011-02-09 17:15:04 +00:00
Chris Lattner 6e57b15228 teach instsimplify to transform (X / Y) * Y to X
when the div is an exact udiv.

llvm-svn: 124994
2011-02-06 22:05:31 +00:00
Chris Lattner 9c70414551 rename test.
llvm-svn: 124993
2011-02-06 21:59:10 +00:00
Duncan Sands 06504025d2 Improve threading of comparisons over select instructions (spotted by my
auto-simplifier).  This has a big impact on Ada code, but not much else.
Unfortunately the impact is mostly negative!  This is due to PR9004 (aka
SCCP failing to resolve conditional branch conditions in the destination
blocks of the branch), in which simple correlated expressions are not
resolved but complicated ones are, so simplifying has a bad effect!

llvm-svn: 124788
2011-02-03 09:37:39 +00:00
Duncan Sands 5747abab10 Reenable the transform "(X*Y)/Y->X" when the multiplication is known not to
overflow (nsw flag), which was disabled because it breaks 254.gap.  I have
informed the GAP authors of the mistake in their code, and arranged for the
testsuite to use -fwrapv when compiling this benchmark.

llvm-svn: 124746
2011-02-02 20:52:00 +00:00
Duncan Sands cf0ff030a8 Have m_One also match constant vectors for which every element is 1.
llvm-svn: 124655
2011-02-01 08:39:12 +00:00
Duncan Sands 2e5a58da8f Commit 124487 broke 254.gap. See if disabling the part that might be triggered
by PR9088 fixes things.

llvm-svn: 124561
2011-01-30 18:24:20 +00:00
Duncan Sands b67edc6a29 Transform (X/Y)*Y into X if the division is exact. Instcombine already knows how
to do this and more, but would only do it if X/Y had only one use.  Spotted as the
most common missed simplification in SPEC by my auto-simplifier, now that it knows
about nuw/nsw/exact flags.  This removes a bunch of multiplications from 447.dealII
and 483.xalancbmk.  It also removes a lot from tramp3d-v4, which results in much
more inlining.

llvm-svn: 124560
2011-01-30 18:03:50 +00:00
Frits van Bommel c2549661af Move InstCombine's knowledge of fdiv to SimplifyInstruction().
llvm-svn: 124534
2011-01-29 15:26:31 +00:00
Duncan Sands 2e9e4f1be3 Fix typo: should have been testing that X was odd, not V.
llvm-svn: 124533
2011-01-29 13:27:00 +00:00
Duncan Sands 771e82a863 My auto-simplifier noticed that ((X/Y)*Y)/Y occurs several times in SPEC
benchmarks, and that it can be simplified to X/Y.  (In general you can only
simplify (Z*Y)/Y to Z if the multiplication did not overflow; if Z has the
form "X/Y" then this is the case).  This patch implements that transform and
moves some Div logic out of instcombine and into InstructionSimplify.
Unfortunately instcombine gets in the way somewhat, since it likes to change
(X/Y)*Y into X-(X rem Y), so I had to teach instcombine about this too.
Finally, thanks to the NSW/NUW flags, sometimes we know directly that "Z*Y"
does not overflow, because the flag says so, so I added that logic too.  This
eliminates a bunch of divisions and subtractions in 447.dealII, and has good
effects on some other benchmarks too.  It seems to have quite an effect on
tramp3d-v4 but it's hard to say if it's good or bad because inlining decisions
changed, resulting in massive changes all over.

llvm-svn: 124487
2011-01-28 16:51:11 +00:00