Chris Lattner
9484689f14
add a note
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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
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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.
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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.
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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.
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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
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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.
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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.
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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
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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.
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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.
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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
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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
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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
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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)
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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
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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.
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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
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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.
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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
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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.
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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.
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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
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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.
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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
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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].
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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
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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
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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.
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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
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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
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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
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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.
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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
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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.
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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.
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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.
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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.
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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.
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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
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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.
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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.
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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.
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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#
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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.
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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.
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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.
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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,
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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.
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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