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283 Commits

Author SHA1 Message Date
Eli Friedman
8c47d3b73f Add README entry; based on testcase from Bill Hart. 
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@105878 91177308-0d34-0410-b5e6-96231b3b80d8
 2010-06-12 05:54:27 +00:00
Chris Lattner
c2685a9c98 add a note 
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@104404 91177308-0d34-0410-b5e6-96231b3b80d8
 2010-05-21 23:16:21 +00:00
Dan Gohman
3a2a4846a6 Add a README entry. 
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@102906 91177308-0d34-0410-b5e6-96231b3b80d8
 2010-05-03 14:31:00 +00:00
Chris Lattner
9484689f14 add a note 
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@101581 91177308-0d34-0410-b5e6-96231b3b80d8
 2010-04-16 23:52:30 +00:00
Chris Lattner
2392ae7d73 Implement rdar://7860110 (also in target/readme.txt) narrowing 
a load/or/and/store sequence into a narrower store when it is
safe.  Daniel tells me that clang will start producing this sort
of thing with bitfields, and this does  trigger a few dozen times
on 176.gcc produced by llvm-gcc even now.

This compiles code like CodeGen/X86/2009-05-28-DAGCombineCrash.ll 
into:

        movl    %eax, 36(%rdi)

instead of:

        movl    $4294967295, %eax       ## imm = 0xFFFFFFFF
        andq    32(%rdi), %rax
        shlq    $32, %rcx
        addq    %rax, %rcx
        movq    %rcx, 32(%rdi)

and each of the testcases into a single store.  Each of them used
to compile into craziness like this:

_test4:
	movl	$65535, %eax            ## imm = 0xFFFF
	andl	(%rdi), %eax
	shll	$16, %esi
	addl	%eax, %esi
	movl	%esi, (%rdi)
	ret




git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@101343 91177308-0d34-0410-b5e6-96231b3b80d8
 2010-04-15 04:48:01 +00:00
Chris Lattner
6663670359 move PR6576 here. 
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@98194 91177308-0d34-0410-b5e6-96231b3b80d8
 2010-03-10 21:42:42 +00:00
Chris Lattner
cf031f6d66 move PR6212 to this file. 
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@95624 91177308-0d34-0410-b5e6-96231b3b80d8
 2010-02-09 00:11:10 +00:00
Eli Friedman
1144d7e3cc Remove a completed item, add a couple new ones. 
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@94945 91177308-0d34-0410-b5e6-96231b3b80d8
 2010-01-31 04:55:32 +00:00
Bob Wilson
3eb4f7e2dd Improve isSafeToLoadUnconditionally to recognize that GEPs with constant 
indices are safe if the result is known to be within the bounds of the
underlying object.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@94829 91177308-0d34-0410-b5e6-96231b3b80d8
 2010-01-29 19:19:08 +00:00
Chris Lattner
43dc2e6d76 reassociate should do this. 
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@94374 91177308-0d34-0410-b5e6-96231b3b80d8
 2010-01-24 20:17:09 +00:00
Chris Lattner
10c4245103 add a note. 
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@94373 91177308-0d34-0410-b5e6-96231b3b80d8
 2010-01-24 20:01:41 +00:00
Chris Lattner
818ff34bc0 implement a simple instcombine xform that has been in the 
readme forever.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@94318 91177308-0d34-0410-b5e6-96231b3b80d8
 2010-01-23 18:49:30 +00:00
Chris Lattner
aa306c2cc1 add some notes, making posix-memalign be nocapture would be an easy improvement. 
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@94312 91177308-0d34-0410-b5e6-96231b3b80d8
 2010-01-23 17:59:23 +00:00
Eli Friedman
9cfb3adf44 Add some potentially interesting transformations to README. 
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@93797 91177308-0d34-0410-b5e6-96231b3b80d8
 2010-01-18 22:36:59 +00:00
Duncan Sands
e10920d678 Fix a README item: have functionattrs look through selects and 
phi nodes when deciding which pointers point to local memory.
I actually checked long ago how useful this is, and it isn't
very: it hardly ever fires in the testsuite, but since Chris
wants it here it is!


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@92836 91177308-0d34-0410-b5e6-96231b3b80d8
 2010-01-06 15:37:47 +00:00
Duncan Sands
7c422ac216 Partially address a README by having functionattrs consider calls to 
memcpy, memset and other intrinsics that only access their arguments
to be readnone if the intrinsic's arguments all point to local memory.
This improves the testcase in the README to readonly, but it could in
theory be made readnone, however this would involve more sophisticated
analysis that looks through the memcpy.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@92829 91177308-0d34-0410-b5e6-96231b3b80d8
 2010-01-06 08:45:52 +00:00
Chris Lattner
e4412c1f0b implement an instcombine xform needed by clang's codegen 
on the example in PR4216.  This doesn't trigger in the testsuite,
so I'd really appreciate someone scrutinizing the logic for
correctness.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@92458 91177308-0d34-0410-b5e6-96231b3b80d8
 2010-01-04 06:03:59 +00:00
Chris Lattner
f031e8ad01 Teach codegen to lower llvm.powi to an efficient (but not optimal) 
multiply sequence when the power is a constant integer.  Before, our
codegen for std::pow(.., int) always turned into a libcall, which was
really inefficient.

This should also make many gfortran programs happier I'd imagine.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@92388 91177308-0d34-0410-b5e6-96231b3b80d8
 2010-01-01 03:32:16 +00:00
Chris Lattner
398ffba75f update this. To take the next step, llvm.powi should be generalized to work 
on integers as well and codegen should lower them to branch trees.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@92382 91177308-0d34-0410-b5e6-96231b3b80d8
 2010-01-01 01:29:26 +00:00
Eli Friedman
bcae205a4b More info on this transformation. 
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@91230 91177308-0d34-0410-b5e6-96231b3b80d8
 2009-12-12 23:23:43 +00:00
Eli Friedman
1555473387 Remove some stuff that's already implemented. Also, remove the note about 
merging x >u 5 and x <s 20 because it's impossible to implement.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@91228 91177308-0d34-0410-b5e6-96231b3b80d8
 2009-12-12 21:41:48 +00:00
Chris Lattner
89742c2c3f expand note. 
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@90429 91177308-0d34-0410-b5e6-96231b3b80d8
 2009-12-03 07:43:46 +00:00
Chris Lattner
053321731c add a note 
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@90428 91177308-0d34-0410-b5e6-96231b3b80d8
 2009-12-03 07:41:54 +00:00
Chris Lattner
d4137f40da update and consolidate the load pre notes. 
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@90050 91177308-0d34-0410-b5e6-96231b3b80d8
 2009-11-29 02:19:52 +00:00
Chris Lattner
1d159838a3 add a deadargelim note. 
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@90009 91177308-0d34-0410-b5e6-96231b3b80d8
 2009-11-27 17:12:30 +00:00
Chris Lattner
6d94926a52 This testcase is actually only partially redundant, and requires 
the FIXME I added yesterday to be implemented.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@90008 91177308-0d34-0410-b5e6-96231b3b80d8
 2009-11-27 16:53:57 +00:00
Chris Lattner
20ce7c0ded this (and probably several others) are now done. 
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@89982 91177308-0d34-0410-b5e6-96231b3b80d8
 2009-11-27 00:35:04 +00:00
Chris Lattner
cc3d0eb483 Teach memdep to phi translate bitcasts. This allows us to compile 
the example in GCC PR16799 to:

LBB1_2:                                                     ## %bb1
	movl	%eax, %eax
	subq	%rax, %rdi
	movq	%rdi, (%rcx)
	movl	(%rdi), %eax
	testl	%eax, %eax
	je	LBB1_2

instead of:

LBB1_2:                                                     ## %bb1
	movl	(%rdi), %ecx
	subq	%rcx, %rdi
	movq	%rdi, (%rax)
	cmpl	$0, (%rdi)
	je	LBB1_2



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@89978 91177308-0d34-0410-b5e6-96231b3b80d8
 2009-11-26 23:41:07 +00:00
Chris Lattner
5d5261c819 Teach basicaa that x|c == x+c when the c bits of x are clear. This 
allows us to compile the example in readme.txt into:

LBB1_1:                                                     ## %bb
	movl	4(%rdx,%rax), %ecx
	movl	%ecx, %esi
	imull	(%rdx,%rax), %esi
	imull	%esi, %ecx
	movl	%esi, 8(%rdx,%rax)
	imull	%ecx, %esi
	movl	%ecx, 12(%rdx,%rax)
	movl	%esi, 16(%rdx,%rax)
	imull	%ecx, %esi
	movl	%esi, 20(%rdx,%rax)
	addq	$16, %rax
	cmpq	$4000, %rax
	jne	LBB1_1

instead of:

LBB1_1: 
	movl	(%rdx,%rax), %ecx
	imull	4(%rdx,%rax), %ecx
	movl	%ecx, 8(%rdx,%rax)
	imull	4(%rdx,%rax), %ecx
	movl	%ecx, 12(%rdx,%rax)
	imull	8(%rdx,%rax), %ecx
	movl	%ecx, 16(%rdx,%rax)
	imull	12(%rdx,%rax), %ecx
	movl	%ecx, 20(%rdx,%rax)
	addq	$16, %rax
	cmpq	$4000, %rax
	jne	LBB1_1

GCC (4.2) doesn't seem to be able to eliminate the loads in this 
testcase either, it generates:

L2:
	movl	(%rdx), %eax
	imull	4(%rdx), %eax
	movl	%eax, 8(%rdx)
	imull	4(%rdx), %eax
	movl	%eax, 12(%rdx)
	imull	8(%rdx), %eax
	movl	%eax, 16(%rdx)
	imull	12(%rdx), %eax
	movl	%eax, 20(%rdx)
	addl	$4, %ecx
	addq	$16, %rdx
	cmpl	$1002, %ecx
	jne	L2




git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@89952 91177308-0d34-0410-b5e6-96231b3b80d8
 2009-11-26 16:26:43 +00:00
Chris Lattner
f6ac4d9dad teach basicaa that A[i] != A[i+1]. 
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@89951 91177308-0d34-0410-b5e6-96231b3b80d8
 2009-11-26 16:18:10 +00:00
Chris Lattner
9c6a0dcf0e update some notes slightly 
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@89913 91177308-0d34-0410-b5e6-96231b3b80d8
 2009-11-26 01:51:18 +00:00
Nick Lewycky
93f9f7a440 Add a complex missed optimization opportunity I came across while investigating 
bug 5438.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@88855 91177308-0d34-0410-b5e6-96231b3b80d8
 2009-11-15 17:51:23 +00:00
Chris Lattner
fc926c2395 another const prop failure. 
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@86848 91177308-0d34-0410-b5e6-96231b3b80d8
 2009-11-11 17:54:02 +00:00
Chris Lattner
6fdfc9c630 add a note 
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@86847 91177308-0d34-0410-b5e6-96231b3b80d8
 2009-11-11 17:51:27 +00:00
Chris Lattner
1742498b5a add a note 
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@86756 91177308-0d34-0410-b5e6-96231b3b80d8
 2009-11-10 23:47:45 +00:00
Chris Lattner
b6ad9153dd I did this a week or two ago 
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@86754 91177308-0d34-0410-b5e6-96231b3b80d8
 2009-11-10 23:40:49 +00:00
Nick Lewycky
f80fcd00b3 Improve tail call elimination to handle the switch statement. 
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@86403 91177308-0d34-0410-b5e6-96231b3b80d8
 2009-11-07 21:10:15 +00:00
Chris Lattner
6c9fab7404 add a note from PR5313 
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@86146 91177308-0d34-0410-b5e6-96231b3b80d8
 2009-11-05 18:19:19 +00:00
Bill Wendling
c872e9c07d Add new note. 
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@85341 91177308-0d34-0410-b5e6-96231b3b80d8
 2009-10-27 23:30:07 +00:00
Bill Wendling
5a56927345 Move and clarify note. 
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@85334 91177308-0d34-0410-b5e6-96231b3b80d8
 2009-10-27 22:48:31 +00:00
Chris Lattner
a1e1446056 this is done. 
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@85041 91177308-0d34-0410-b5e6-96231b3b80d8
 2009-10-25 06:17:51 +00:00
Chris Lattner
9ff9b34dd1 some stuff is done, we still have constantexpr simplification to do. 
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@84943 91177308-0d34-0410-b5e6-96231b3b80d8
 2009-10-23 07:00:55 +00:00
Chris Lattner
7d26443bb7 IPSCCP is missing stuff. 
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@84725 91177308-0d34-0410-b5e6-96231b3b80d8
 2009-10-21 01:10:37 +00:00
Chris Lattner
faa6adf67c add a note 
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@82442 91177308-0d34-0410-b5e6-96231b3b80d8
 2009-09-21 06:04:07 +00:00
Chris Lattner
93c6c77340 one case handled, expanded another testcase inline. 
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@82427 91177308-0d34-0410-b5e6-96231b3b80d8
 2009-09-21 02:53:57 +00:00
Chris Lattner
c1491f3c47 update an entry, delete an entry which has been fixed. 
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@82398 91177308-0d34-0410-b5e6-96231b3b80d8
 2009-09-20 17:37:38 +00:00
Nick Lewycky
149cbc2a24 Peer through zext and sext to eliminate them when it is safe to do so. 
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@82389 91177308-0d34-0410-b5e6-96231b3b80d8
 2009-09-20 07:31:25 +00:00
Chris Lattner
c2b0d484dc add PR# 
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@81770 91177308-0d34-0410-b5e6-96231b3b80d8
 2009-09-14 16:49:26 +00:00
Dan Gohman
9ca9daad21 Transform -X/C to X/-C, implementing a README.txt entry. 
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@78812 91177308-0d34-0410-b5e6-96231b3b80d8
 2009-08-12 16:37:02 +00:00
Eli Friedman
58bb61ae94 Remove a couple of already-implemented notes. 
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@76631 91177308-0d34-0410-b5e6-96231b3b80d8
 2009-07-21 20:05:43 +00:00
Nick Lewycky
f16120475e Move PR4517 to README.txt. 
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@75098 91177308-0d34-0410-b5e6-96231b3b80d8
 2009-07-09 04:03:30 +00:00
Dan Gohman
81db61a2e6 Factor the code for collecting IV users out of LSR into an IVUsers class, 
and generalize it so that it can be used by IndVarSimplify. Implement the
base IndVarSimplify transformation code using IVUsers. This removes
TestOrigIVForWrap and associated code, as ScalarEvolution now has enough
builtin overflow detection and folding logic to handle all the same cases,
and more. Run "opt -iv-users -analyze -disable-output" on your favorite
loop for an example of what IVUsers does.

This lets IndVarSimplify eliminate IV casts and compute trip counts in
more cases. Also, this happens to finally fix the remaining testcases
in PR1301.

Now that IndVarSimplify is being more aggressive, it occasionally runs
into the problem where ScalarEvolutionExpander's code for avoiding
duplicate expansions makes it difficult to ensure that all expanded
instructions dominate all the instructions that will use them. As a
temporary measure, IndVarSimplify now uses a FixUsesBeforeDefs function
to fix up instructions inserted by SCEVExpander. Fortunately, this code
is contained, and can be easily removed once a more comprehensive
solution is available.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@71535 91177308-0d34-0410-b5e6-96231b3b80d8
 2009-05-12 02:17:14 +00:00
Dan Gohman
1f3be1a1fe Fix two wording errors that Duncan spotted. 
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@71459 91177308-0d34-0410-b5e6-96231b3b80d8
 2009-05-11 18:51:16 +00:00
Dan Gohman
0d9bb68d6d LLVM has unaligned loads and stores now. 
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@71449 91177308-0d34-0410-b5e6-96231b3b80d8
 2009-05-11 18:06:05 +00:00
Dan Gohman
5c8274b5e3 Upgrade this example to new-style syntax. 
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@71447 91177308-0d34-0410-b5e6-96231b3b80d8
 2009-05-11 18:04:52 +00:00
Chris Lattner
32c5f17024 remove some done things: we have nocapture and SROA is smarter. 
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@71443 91177308-0d34-0410-b5e6-96231b3b80d8
 2009-05-11 17:41:40 +00:00
Chris Lattner
d919a8bc8a add a note 
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@71442 91177308-0d34-0410-b5e6-96231b3b80d8
 2009-05-11 17:36:33 +00:00
Eli Friedman
cea03cdb69 Remove a completed optimization. Add a potential optimization I ran 
into.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@71352 91177308-0d34-0410-b5e6-96231b3b80d8
 2009-05-09 08:40:15 +00:00
Chris Lattner
352f3e5d37 add a note 
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@67953 91177308-0d34-0410-b5e6-96231b3b80d8
 2009-03-28 19:26:55 +00:00
Nick Lewycky
20babb112c Add a totally synthetic situation I came up with while looking at a bug in 
related code.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@65437 91177308-0d34-0410-b5e6-96231b3b80d8
 2009-02-25 06:52:48 +00:00
Torok Edwin
474479fce7 add note about sin 
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@65137 91177308-0d34-0410-b5e6-96231b3b80d8
 2009-02-20 18:42:06 +00:00
Torok Edwin
e46a686dc2 add note about possible GEP improvement with fields of size 0. 
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@62925 91177308-0d34-0410-b5e6-96231b3b80d8
 2009-01-24 19:30:25 +00:00
Chris Lattner
256baa4b1f add a note 
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@62760 91177308-0d34-0410-b5e6-96231b3b80d8
 2009-01-22 07:16:03 +00:00
Dan Gohman
8289b05c4c Add a README entry noticed while investigating PR3216. 
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@62558 91177308-0d34-0410-b5e6-96231b3b80d8
 2009-01-20 01:07:33 +00:00
Chris Lattner
9fee08fce7 add some more crazy strlen and memcpy stuff I noticed in spec. 
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@61918 91177308-0d34-0410-b5e6-96231b3b80d8
 2009-01-08 07:34:55 +00:00
Chris Lattner
ffb08f569b add some notes about strlen craziness in eon. 
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@61917 91177308-0d34-0410-b5e6-96231b3b80d8
 2009-01-08 06:52:57 +00:00
Chris Lattner
d23b799d7d add a note 
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@61513 91177308-0d34-0410-b5e6-96231b3b80d8
 2008-12-31 00:54:13 +00:00
Chris Lattner
9cf8ef63c6 add some notes for simplifylibcalls optimizations 
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@61385 91177308-0d34-0410-b5e6-96231b3b80d8
 2008-12-23 20:52:52 +00:00
Chris Lattner
582048d5b8 add some more notes. 
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@61033 91177308-0d34-0410-b5e6-96231b3b80d8
 2008-12-15 08:32:28 +00:00
Chris Lattner
8f416f3afd Add a testcase for GCC PR 23455, which lpre handles now. Add some 
comments about why we're not getting other cases.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@61032 91177308-0d34-0410-b5e6-96231b3b80d8
 2008-12-15 07:49:24 +00:00
Chris Lattner
ef423ebdd1 gvn now hoists this load out of the hot non-call path. 
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@61028 91177308-0d34-0410-b5e6-96231b3b80d8
 2008-12-15 06:34:48 +00:00
Chris Lattner
2dae65d13b move an entry, add some notes, remove a completed item (IMPLICIT_DEF) 
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@60821 91177308-0d34-0410-b5e6-96231b3b80d8
 2008-12-10 01:30:48 +00:00
Chris Lattner
630c99fd21 improve a note. 
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@60636 91177308-0d34-0410-b5e6-96231b3b80d8
 2008-12-07 00:15:10 +00:00
Chris Lattner
6a09a74e46 some more PRE/GVN/DSE related notes. 
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@60633 91177308-0d34-0410-b5e6-96231b3b80d8
 2008-12-06 22:52:12 +00:00
Chris Lattner
78a7e7c797 some random notes. 
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@60624 91177308-0d34-0410-b5e6-96231b3b80d8
 2008-12-06 19:28:22 +00:00
Chris Lattner
88d84b245c add a note 
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@60404 91177308-0d34-0410-b5e6-96231b3b80d8
 2008-12-02 06:32:34 +00:00
Bill Wendling
3bdcda82a5 - Remove the buggy -X/C -> X/-C transform. This isn't valid when X isn't a 
constant. If X is a constant, then this is folded elsewhere.

- Added a note to Target/README.txt to indicate that we'd like to implement
  this when we're able.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@60399 91177308-0d34-0410-b5e6-96231b3b80d8
 2008-12-02 05:12:47 +00:00
Bill Wendling
b3833d1eb9 Implement ((A|B)&1)|(B&-2) -> (A&1) | B transformation. This also takes care of 
permutations of this pattern.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@60312 91177308-0d34-0410-b5e6-96231b3b80d8
 2008-12-01 01:07:11 +00:00
Bill Wendling
b01865c210 Add instruction combining for ((A&~B)|(~A&B)) -> A^B and all permutations. 
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@60291 91177308-0d34-0410-b5e6-96231b3b80d8
 2008-11-30 13:52:49 +00:00
Bill Wendling
7f0ef6b325 Implement (A&((~A)|B)) -> A&B transformation in the instruction combiner. This 
takes care of all permutations of this pattern.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@60290 91177308-0d34-0410-b5e6-96231b3b80d8
 2008-11-30 13:08:13 +00:00
Eli Friedman
4e16b29a6b Moving potential optimizations out of PR2330 into lib/Target/README.txt. 
Hopefully this isn't too much stuff to dump into this file.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@60285 91177308-0d34-0410-b5e6-96231b3b80d8
 2008-11-30 07:36:04 +00:00
Nick Lewycky
d2f0db1b19 Also update the README. 
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@60188 91177308-0d34-0410-b5e6-96231b3b80d8
 2008-11-27 22:41:45 +00:00
Nick Lewycky
df563ca1f3 Add a synthetic missed optimization. 
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@60186 91177308-0d34-0410-b5e6-96231b3b80d8
 2008-11-27 22:12:22 +00:00
Torok Edwin
61df3b751a move the note to the correct README 
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@58104 91177308-0d34-0410-b5e6-96231b3b80d8
 2008-10-24 19:23:07 +00:00
Torok Edwin
db1b3bc276 add note about va_arg code on x86 and x86-64 
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@58103 91177308-0d34-0410-b5e6-96231b3b80d8
 2008-10-24 19:20:05 +00:00
Dan Gohman
cb747c558c This is now partly done. 
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@57734 91177308-0d34-0410-b5e6-96231b3b80d8
 2008-10-17 21:39:27 +00:00
Chris Lattner
3b364cb986 move PR1941 here. 
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@57586 91177308-0d34-0410-b5e6-96231b3b80d8
 2008-10-15 16:33:52 +00:00
Chris Lattner
db03983238 move PR1604 here. 
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@57582 91177308-0d34-0410-b5e6-96231b3b80d8
 2008-10-15 16:06:03 +00:00
Chris Lattner
f4fee2a976 move PR1488 into this file. 
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@57579 91177308-0d34-0410-b5e6-96231b3b80d8
 2008-10-15 16:02:15 +00:00
Chris Lattner
b7fe708b32 add a note 
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@57557 91177308-0d34-0410-b5e6-96231b3b80d8
 2008-10-15 05:53:25 +00:00
Chris Lattner
b1ac769873 this case is matched now. 
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@57096 91177308-0d34-0410-b5e6-96231b3b80d8
 2008-10-05 02:16:12 +00:00
Chris Lattner
23f35bc3ae add a note 
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@54985 91177308-0d34-0410-b5e6-96231b3b80d8
 2008-08-19 06:22:16 +00:00
Chris Lattner
26e150f361 move some more stuff out of my email into readme.txt 
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@54603 91177308-0d34-0410-b5e6-96231b3b80d8
 2008-08-10 01:14:08 +00:00
Chris Lattner
c90b866797 add a note 
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@54602 91177308-0d34-0410-b5e6-96231b3b80d8
 2008-08-10 00:47:21 +00:00
Chris Lattner
10c5d36ca9 Add a note. 
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@53535 91177308-0d34-0410-b5e6-96231b3b80d8
 2008-07-14 00:19:59 +00:00
Nick Lewycky
517e1f5cd7 Peer through sext/zext when looking for not(cmp). 
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@51819 91177308-0d34-0410-b5e6-96231b3b80d8
 2008-05-31 19:01:33 +00:00
Nick Lewycky
4914db09a5 Yay us! Every one of these examples turns into icmp/zext/ret. 
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@51818 91177308-0d34-0410-b5e6-96231b3b80d8
 2008-05-31 18:20:26 +00:00
Chris Lattner
b5783106c4 trip count computation deficiency 
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@51222 91177308-0d34-0410-b5e6-96231b3b80d8
 2008-05-17 15:37:38 +00:00
Nick Lewycky
8dd6505868 Moved from PR1570. 
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@48965 91177308-0d34-0410-b5e6-96231b3b80d8
 2008-03-30 19:07:11 +00:00
Chris Lattner
f70107fe1c add a note. 
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@48583 91177308-0d34-0410-b5e6-96231b3b80d8
 2008-03-20 04:46:13 +00:00
Chris Lattner
349155b671 various rotate fun. 
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@48438 91177308-0d34-0410-b5e6-96231b3b80d8
 2008-03-17 01:47:51 +00:00
Chris Lattner
53b7277917 another random note 
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@47831 91177308-0d34-0410-b5e6-96231b3b80d8
 2008-03-02 19:29:42 +00:00
Chris Lattner
a11deb0392 Move pr717 to here. 
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@47803 91177308-0d34-0410-b5e6-96231b3b80d8
 2008-03-02 02:51:40 +00:00
Chris Lattner
e29536ca8d add a note 
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@47720 91177308-0d34-0410-b5e6-96231b3b80d8
 2008-02-28 17:21:27 +00:00
Chris Lattner
48840f8db9 target-indep codegen memcpy lowering issue. 
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@47705 91177308-0d34-0410-b5e6-96231b3b80d8
 2008-02-28 05:34:27 +00:00
Chris Lattner
7c4e9a44a4 upgrade some tests. 
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@47280 91177308-0d34-0410-b5e6-96231b3b80d8
 2008-02-18 18:46:39 +00:00
Nate Begeman
e9fe65c973 Add a note 
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@47279 91177308-0d34-0410-b5e6-96231b3b80d8
 2008-02-18 18:39:23 +00:00
Chris Lattner
65844fbd84 clarify a note 
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@45914 91177308-0d34-0410-b5e6-96231b3b80d8
 2008-01-12 18:58:46 +00:00
Chris Lattner
497b7e97c0 add some notes. 
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@45854 91177308-0d34-0410-b5e6-96231b3b80d8
 2008-01-11 06:17:47 +00:00
Chris Lattner
8372601521 add a note 
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@45837 91177308-0d34-0410-b5e6-96231b3b80d8
 2008-01-10 18:25:41 +00:00
Chris Lattner
f61b63ec5b add a note 
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@45766 91177308-0d34-0410-b5e6-96231b3b80d8
 2008-01-09 00:17:57 +00:00
Chris Lattner
b3041948eb possible switch lowering improvement. 
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@45720 91177308-0d34-0410-b5e6-96231b3b80d8
 2008-01-07 21:38:14 +00:00
Chris Lattner
4e4e46143a add a note 
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@45698 91177308-0d34-0410-b5e6-96231b3b80d8
 2008-01-07 07:46:23 +00:00
Chris Lattner
a5e90d7b74 this is done. 
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@45408 91177308-0d34-0410-b5e6-96231b3b80d8
 2007-12-29 19:38:02 +00:00
Chris Lattner
92c06a01de expand note. 
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@45393 91177308-0d34-0410-b5e6-96231b3b80d8
 2007-12-29 01:05:01 +00:00
Chris Lattner
a1643ba71a add a note. 
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@45388 91177308-0d34-0410-b5e6-96231b3b80d8
 2007-12-28 22:30:05 +00:00
Chris Lattner
166a268656 add a note 
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@45377 91177308-0d34-0410-b5e6-96231b3b80d8
 2007-12-28 04:42:05 +00:00
Christopher Lamb
30f017ad89 Fold certain additions through selects (and their compares) so as to eliminate subtractions. This code is often produced by the SMAX expansion in SCEV. 
This implements test/Transforms/InstCombine/2007-12-18-AddSelCmpSub.ll


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@45158 91177308-0d34-0410-b5e6-96231b3b80d8
 2007-12-18 09:34:41 +00:00
Chris Lattner
fd2025e9db add a missed case. 
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@45141 91177308-0d34-0410-b5e6-96231b3b80d8
 2007-12-18 01:19:18 +00:00
Chris Lattner
e70da20f9a implement a readme entry, compiling the code into: 
_foo:
	movl	$12, %eax
	andl	4(%esp), %eax
	movl	_array(%eax), %eax
	ret

instead of:

_foo:
	movl	4(%esp), %eax
	shrl	$2, %eax
	andl	$3, %eax
	movl	_array(,%eax,4), %eax
	ret

As it turns out, this triggers all the time, in a wide variety of
situations, for example, I see diffs like this in various programs:

-       movl    8(%eax), %eax
-       shll    $2, %eax
-       andl    $1020, %eax
-       movl    (%esi,%eax), %eax
+       movzbl  8(%eax), %eax
+       movl    (%esi,%eax,4), %eax


-       shll    $2, %edx
-       andl    $1020, %edx
-       movl    (%edi,%edx), %edx
+       andl    $255, %edx
+       movl    (%edi,%edx,4), %edx

Unfortunately, I also see stuff like this, which can be fixed in the
X86 backend:

-       andl    $85, %ebx
-       addl    _bit_count(,%ebx,4), %ebp
+       shll    $2, %ebx
+       andl    $340, %ebx
+       addl    _bit_count(%ebx), %ebp



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@44656 91177308-0d34-0410-b5e6-96231b3b80d8
 2007-12-06 07:33:36 +00:00
Chris Lattner
81f2d71d52 add a note 
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@44638 91177308-0d34-0410-b5e6-96231b3b80d8
 2007-12-05 23:05:06 +00:00
Chris Lattner
e1bb6ab7b0 add a note 
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@42573 91177308-0d34-0410-b5e6-96231b3b80d8
 2007-10-03 06:10:59 +00:00
Chris Lattner
f110a2bdb6 add a note 
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@36811 91177308-0d34-0410-b5e6-96231b3b80d8
 2007-05-05 22:44:08 +00:00
Chris Lattner
5e14b0d3e6 the mason example is implemented. Move some examples out of llvm/test, 
upgrade the syntax of some other examples.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@36806 91177308-0d34-0410-b5e6-96231b3b80d8
 2007-05-05 22:29:06 +00:00
Chris Lattner
1a77a556cd add a bad case evan though of. 
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@35296 91177308-0d34-0410-b5e6-96231b3b80d8
 2007-03-24 06:01:32 +00:00
Chris Lattner
11a3a9d27d minor updates 
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@35143 91177308-0d34-0410-b5e6-96231b3b80d8
 2007-03-18 22:41:33 +00:00
Nick Lewycky
7f4ba44f37 This is implemented. We now generate: 
entry:
        icmp ugt i32 %x, 4              ; <i1>:0 [#uses=1]
        br i1 %0, label %cond_true, label %cond_false

cond_true:              ; preds = %entry
        %tmp1 = tail call i32 (...)* @bar( i32 12 )             ; <i32> [#uses=0]
        ret void

cond_false:             ; preds = %entry
        switch i32 %x, label %cond_true15 [
                 i32 4, label %cond_true3
                 i32 3, label %cond_true7
                 i32 2, label %cond_true11
                 i32 0, label %cond_false17
        ]

...


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@35142 91177308-0d34-0410-b5e6-96231b3b80d8
 2007-03-18 14:37:20 +00:00
Reid Spencer
ac9dcb94dd For PR1195: 
Change use of "packed" term to "vector" in comments, strings, variable
names, etc.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@34300 91177308-0d34-0410-b5e6-96231b3b80d8
 2007-02-15 03:39:18 +00:00
Chris Lattner
36e37d2944 add a note 
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@34249 91177308-0d34-0410-b5e6-96231b3b80d8
 2007-02-13 21:44:43 +00:00
Chris Lattner
03a6d96d32 add a note: we need whole-function selectiondags :) 
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@33252 91177308-0d34-0410-b5e6-96231b3b80d8
 2007-01-16 06:39:48 +00:00
Reid Spencer
e4d87aa2de For PR950: 
This patch removes the SetCC instructions and replaces them with the ICmp
and FCmp instructions. The SetCondInst instruction has been removed and
been replaced with ICmpInst and FCmpInst.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@32751 91177308-0d34-0410-b5e6-96231b3b80d8
 2006-12-23 06:05:41 +00:00
Chris Lattner
a5546fbd10 Evan implemented the machineinstr improvements. 
The rot example works if the type is cast to ubyte.

Move sroa examples together and upgrade them to HEAD syntax.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@32423 91177308-0d34-0410-b5e6-96231b3b80d8
 2006-12-11 00:44:03 +00:00
Chris Lattner
f9bae438aa add a note 
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@32347 91177308-0d34-0410-b5e6-96231b3b80d8
 2006-12-08 02:01:32 +00:00
Chris Lattner
641c523599 done 
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@32013 91177308-0d34-0410-b5e6-96231b3b80d8
 2006-11-29 07:21:46 +00:00
Chris Lattner
9b62b458c5 add a note 
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@31719 91177308-0d34-0410-b5e6-96231b3b80d8
 2006-11-14 01:57:53 +00:00
Nick Lewycky
bf63734a1b Cute example from Chris Lattner. 
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@31696 91177308-0d34-0410-b5e6-96231b3b80d8
 2006-11-13 00:23:28 +00:00
Chris Lattner
578d2df84b add a note about viterbi 
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@31612 91177308-0d34-0410-b5e6-96231b3b80d8
 2006-11-10 00:23:26 +00:00
Chris Lattner
8c97c07040 add a note 
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@31477 91177308-0d34-0410-b5e6-96231b3b80d8
 2006-11-06 21:26:49 +00:00
Chris Lattner
d7c628de89 add a note 
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@31429 91177308-0d34-0410-b5e6-96231b3b80d8
 2006-11-03 22:27:39 +00:00
Reid Spencer
1628cec4d7 For PR950: 
Make necessary changes to support DIV -> [SUF]Div. This changes llvm to
have three division instructions: signed, unsigned, floating point. The
bytecode and assembler are bacwards compatible, however.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@31195 91177308-0d34-0410-b5e6-96231b3b80d8
 2006-10-26 06:15:43 +00:00
Chris Lattner
cf10391a72 new bad case 
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@31156 91177308-0d34-0410-b5e6-96231b3b80d8
 2006-10-24 16:12:47 +00:00
Chris Lattner
f308ea01d5 add a note about a general improvement to the code generator 
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@30642 91177308-0d34-0410-b5e6-96231b3b80d8
 2006-09-28 06:01:17 +00:00
Chris Lattner
fb981f3fee more notes 
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@30598 91177308-0d34-0410-b5e6-96231b3b80d8
 2006-09-25 17:12:14 +00:00
Chris Lattner
f529b08c0d item done 
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@30483 91177308-0d34-0410-b5e6-96231b3b80d8
 2006-09-19 06:19:03 +00:00
Chris Lattner
b33a42a21f This is closer to what we really want. 
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@30451 91177308-0d34-0410-b5e6-96231b3b80d8
 2006-09-18 04:54:35 +00:00
Chris Lattner
7ed96abc09 add a note noticed through source inspection 
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@30418 91177308-0d34-0410-b5e6-96231b3b80d8
 2006-09-16 23:57:51 +00:00
Chris Lattner
cbce2f6c1b add a nate note 
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@30399 91177308-0d34-0410-b5e6-96231b3b80d8
 2006-09-15 20:31:36 +00:00
Chris Lattner
bf16982e86 We compile this into: 
_swap_16:
        slwi r2, r3, 24
        rlwimi r2, r3, 8, 8, 15
        srwi r3, r2, 16
        blr

now.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@29864 91177308-0d34-0410-b5e6-96231b3b80d8
 2006-08-24 23:06:02 +00:00
Chris Lattner
ad69970c4a Owen implemented this. 
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@29863 91177308-0d34-0410-b5e6-96231b3b80d8
 2006-08-24 23:03:33 +00:00
Chris Lattner
9e18ef5262 Add a note 
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@28572 91177308-0d34-0410-b5e6-96231b3b80d8
 2006-05-30 21:29:15 +00:00