Commit Graph

82 Commits

Author SHA1 Message Date
Chad Rosier e27081d348 Revert r153521 as it's causing large regressions on the nightly testers.
Original commit message for r153521 (aka r153423):
Use the new range metadata in computeMaskedBits and add a new optimization to
instruction simplify that lets us remove an and when loding a boolean value.

llvm-svn: 153587
2012-03-28 18:42:50 +00:00
Chad Rosier 8e6dbccd03 Reapply r153423; the original commit was fine. The failing test, distray, had
undefined behavior, which Rafael was kind enough to fix.

Original commit message for r153423:
Use the new range metadata in computeMaskedBits and add a new optimization to
instruction simplify that lets us remove an and when loding a boolean value.

llvm-svn: 153521
2012-03-27 17:44:52 +00:00
Chad Rosier 08e57e5ccf Revert r153423 as this is causing failures on our internal nightly testers.
Original commit message:
Use the new range metadata in computeMaskedBits and add a new optimization to
instruction simplify that lets us remove an and when loading a boolean value.

llvm-svn: 153452
2012-03-26 18:07:14 +00:00
Rafael Espindola df9b4adb82 Use the new range metadata in computeMaskedBits and add a new optimization to
instruction simplify that lets us remove an and when loding a boolean value.

llvm-svn: 153423
2012-03-26 01:44:11 +00:00
Chandler Carruth 8059c84af1 Teach instsimplify how to simplify comparisons of pointers which are
constant-offsets of a common base using the generic GEP-walking logic
I added for computing pointer differences in the same situation.

llvm-svn: 153419
2012-03-25 21:28:14 +00:00
Chandler Carruth 2741aae80b Switch the pointer-difference simplification logic to only work with
inbounds GEPs. This isn't really necessary for simplifying pointer
differences, but I'm planning to re-use the same code to simplify
pointer comparisons where it is necessary. Since real code almost
exclusively uses inbounds GEPs, it doesn't seem worth it to support the
extra complexity of turning it on and off. If anyone would like that
back, feel free to shout. Note that instcombine will still catch any of
these patterns.

llvm-svn: 153418
2012-03-25 20:43:07 +00:00
Duncan Sands 395ac42dd2 Generalize the "trunc(ptrtoint(x)) - trunc(ptrtoint(y)) ->
trunc(ptrtoint(x-y))" optimization introduced by Chandler.

llvm-svn: 152626
2012-03-13 14:07:05 +00:00
Chandler Carruth a0796555e2 Teach instsimplify how to constant fold pointer differences.
Typically instcombine has handled this, but pointer differences show up
in several contexts where we would like to get constant folding, and
cannot afford to run instcombine. Specifically, I'm working on improving
the constant folding of arguments used in inline cost analysis with
instsimplify.

Doing this in instsimplify implies some algorithm changes. We have to
handle multiple layers of all-constant GEPs because instsimplify cannot
fold them into a single GEP the way instcombine can. Also, we're only
interested in all-constant GEPs. The result is that this doesn't really
replace the instcombine logic, it's just complimentary and focused on
constant folding.

Reviewed on IRC by Benjamin Kramer.

llvm-svn: 152555
2012-03-12 11:19:31 +00:00
Eli Friedman a8b75ac798 Make sure we don't return bits outside the mask in ComputeMaskedBits. PR12189.
llvm-svn: 152066
2012-03-05 23:09:40 +00:00
Nick Lewycky 3db143ea8c Reinstate the optimization from r151449 with a fix to not turn 'gep %x' into
'gep null' when the icmp predicate is unsigned (or is signed without inbounds).

llvm-svn: 151467
2012-02-26 02:09:49 +00:00
Nick Lewycky 7bbd72da46 Roll these back to r151448 until I figure out how they're breaking
MultiSource/Applications/lua.

llvm-svn: 151463
2012-02-25 23:01:19 +00:00
Nick Lewycky eeeffbb497 An argument and a local identified object (eg. a noalias call) could turn out
equal if both are null. In the test, scope type %t and global @y by adding a
'gep' prefix to them.

llvm-svn: 151452
2012-02-25 20:19:07 +00:00
Nick Lewycky 51f2be8bff Teach instsimplify to be more aggressive when analyzing comparisons of pointers
by using llvm::isIdentifiedObject. Also teach it to handle GEPs that have
the same base pointer and constant operands. Fixes PR11238!

llvm-svn: 151449
2012-02-25 19:07:42 +00:00
Chris Lattner 01990f0e1c fix PR12075, a regression in a recent transform I added. In unreachable code, gep chains can be infinite. Just like "stripPointerCasts", use a set to keep track of visited instructions so we don't recurse infinitely.
llvm-svn: 151383
2012-02-24 19:01:58 +00:00
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