Commit Graph

179 Commits

Author SHA1 Message Date
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