Eli Friedman
97ab5803df
A bit more analysis of a memset-related README entry.
...
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@128107 91177308-0d34-0410-b5e6-96231b3b80d8
2011-03-22 20:49:53 +00:00
Eli Friedman
ddfa02ba24
This README entry was fixed recently.
...
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@127982 91177308-0d34-0410-b5e6-96231b3b80d8
2011-03-21 01:33:03 +00:00
Chris Lattner
d3e768ecab
add a note
...
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@126719 91177308-0d34-0410-b5e6-96231b3b80d8
2011-03-01 00:24:51 +00:00
Benjamin Kramer
7466678003
Add some DAGCombines for (adde 0, 0, glue), which are useful to optimize legalized code for large integer arithmetic.
...
1. Inform users of ADDEs with two 0 operands that it never sets carry
2. Fold other ADDs or ADDCs into the ADDE if possible
It would be neat if we could do the same thing for SETCC+ADD eventually, but we can't do that in target independent code.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@126557 91177308-0d34-0410-b5e6-96231b3b80d8
2011-02-26 22:48:07 +00:00
Chris Lattner
19310fc199
add a missed loop deletion case.
...
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@126103 91177308-0d34-0410-b5e6-96231b3b80d8
2011-02-21 02:13:39 +00:00
Chris Lattner
477a98824a
add an idiom that loop idiom could theoretically catch.
...
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@126101 91177308-0d34-0410-b5e6-96231b3b80d8
2011-02-21 01:33:38 +00:00
Duncan Sands
fe167c5a14
This has been implemented.
...
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@125738 91177308-0d34-0410-b5e6-96231b3b80d8
2011-02-17 08:16:56 +00:00
Chris Lattner
cb40195641
add some notes on compares + binops. Remove redundant entries.
...
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@125702 91177308-0d34-0410-b5e6-96231b3b80d8
2011-02-17 01:43:46 +00:00
Chris Lattner
5653f1f904
Add a few missed xforms from GCC PR14753
...
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@125681 91177308-0d34-0410-b5e6-96231b3b80d8
2011-02-16 19:16:34 +00:00
Eli Friedman
eb1dc98aa7
Remove outdated README entry.
...
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@125660 91177308-0d34-0410-b5e6-96231b3b80d8
2011-02-16 07:41:19 +00:00
Eli Friedman
fd51e95171
Remove outdated README entry.
...
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@125659 91177308-0d34-0410-b5e6-96231b3b80d8
2011-02-16 07:18:18 +00:00
Eli Friedman
c5cb996e9c
Update README entry.
...
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@125658 91177308-0d34-0410-b5e6-96231b3b80d8
2011-02-16 07:17:44 +00:00
Anders Carlsson
9c93d48b6b
Remove a virtual inheritance case that clang can devirtualize fully now.
...
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@124989 91177308-0d34-0410-b5e6-96231b3b80d8
2011-02-06 20:16:49 +00:00
Benjamin Kramer
56442dfdcf
SimplifyCFG: Turn switches into sub+icmp+branch if possible.
...
This makes the job of the later optzn passes easier, allowing the vast amount of
icmp transforms to chew on it.
We transform 840 switches in gcc.c, leading to a 16k byte shrink of the resulting
binary on i386-linux.
The testcase from README.txt now compiles into
decl %edi
cmpl $3, %edi
sbbl %eax, %eax
andl $1, %eax
ret
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@124724 91177308-0d34-0410-b5e6-96231b3b80d8
2011-02-02 15:56:22 +00:00
Chris Lattner
fd2ad8783c
add a note, progress unblocked by PR8575 being fixed.
...
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@124599 91177308-0d34-0410-b5e6-96231b3b80d8
2011-01-31 20:23:28 +00:00
Benjamin Kramer
9b108a338d
Teach DAGCombine to fold fold (sra (trunc (sr x, c1)), c2) -> (trunc (sra x, c1+c2) when c1 equals the amount of bits that are truncated off.
...
This happens all the time when a smul is promoted to a larger type.
On x86-64 we now compile "int test(int x) { return x/10; }" into
movslq %edi, %rax
imulq $1717986919, %rax, %rax
movq %rax, %rcx
shrq $63, %rcx
sarq $34, %rax <- used to be "shrq $32, %rax; sarl $2, %eax"
addl %ecx, %eax
This fires 96 times in gcc.c on x86-64.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@124559 91177308-0d34-0410-b5e6-96231b3b80d8
2011-01-30 16:38:43 +00:00
Chris Lattner
96c0771c01
this isn't a memset, we do convert dest[i] to one though :)
...
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@124097 91177308-0d34-0410-b5e6-96231b3b80d8
2011-01-24 02:32:00 +00:00
Chris Lattner
7ea7d32de6
with recent work, we now optimize this into:
...
define i32 @foo(i32 %x) nounwind readnone ssp {
entry:
%tobool = icmp eq i32 %x, 0
%tmp5 = select i1 %tobool, i32 2, i32 1
ret i32 %tmp5
}
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@124091 91177308-0d34-0410-b5e6-96231b3b80d8
2011-01-24 01:12:18 +00:00
Anders Carlsson
f330b3227a
Add a memset loop that LoopIdiomRecognize doesn't recognize.
...
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@124082 91177308-0d34-0410-b5e6-96231b3b80d8
2011-01-23 20:31:00 +00:00
Chris Lattner
908d8e82b5
add a note
...
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@123752 91177308-0d34-0410-b5e6-96231b3b80d8
2011-01-18 07:47:48 +00:00
Anders Carlsson
5822b86e4d
Update README.txt to remove the DAE enhancement.
...
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@123597 91177308-0d34-0410-b5e6-96231b3b80d8
2011-01-16 21:26:15 +00:00
Chris Lattner
b0daffc609
add some commentary
...
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@123572 91177308-0d34-0410-b5e6-96231b3b80d8
2011-01-16 06:39:44 +00:00
Chandler Carruth
cad33c624e
Simplify a README.txt entry significantly to expose the core issue.
...
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@123556 91177308-0d34-0410-b5e6-96231b3b80d8
2011-01-16 01:40:23 +00:00
Chris Lattner
4c5456a56f
typo
...
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@123406 91177308-0d34-0410-b5e6-96231b3b80d8
2011-01-13 22:11:56 +00:00
Chris Lattner
4cd18f98f7
memcpy + metadata = bliss :)
...
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@123405 91177308-0d34-0410-b5e6-96231b3b80d8
2011-01-13 22:08:15 +00:00
Chandler Carruth
15ed90c859
Teach constant folding to perform conversions from constant floating
...
point values to their integer representation through the SSE intrinsic
calls. This is the last part of a README.txt entry for which I have real
world examples.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@123206 91177308-0d34-0410-b5e6-96231b3b80d8
2011-01-11 01:07:24 +00:00
Owen Anderson
da1c122da5
Fix a random missed optimization by making InstCombine more aggressive when determining which bits are demanded by
...
a comparison against a constant.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@123203 91177308-0d34-0410-b5e6-96231b3b80d8
2011-01-11 00:36:45 +00:00
Chris Lattner
4a6fb94c40
+0.0 vs -0.0 differences can be handled by looking at the user of the
...
operation in some cases.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@123190 91177308-0d34-0410-b5e6-96231b3b80d8
2011-01-10 21:01:17 +00:00
Chris Lattner
00a35d0f14
expand on a note
...
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@123145 91177308-0d34-0410-b5e6-96231b3b80d8
2011-01-10 00:33:01 +00:00
Chris Lattner
66d7a5793c
typo
...
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@123142 91177308-0d34-0410-b5e6-96231b3b80d8
2011-01-09 23:48:41 +00:00
Chris Lattner
7cc4e304a6
xref a PR #
...
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@123141 91177308-0d34-0410-b5e6-96231b3b80d8
2011-01-09 23:42:22 +00:00
Chandler Carruth
fb00e2715b
Add a note about the inability to model FP -> int conversions which
...
perform rounding other than truncation in the IR. Common C code for this
turns into really an LLVM intrinsic call that blocks a lot of further
optimizations.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@123135 91177308-0d34-0410-b5e6-96231b3b80d8
2011-01-09 22:36:18 +00:00
Chandler Carruth
96b1b6c135
Add a note about a missed FP optimization.
...
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@123126 91177308-0d34-0410-b5e6-96231b3b80d8
2011-01-09 21:00:19 +00:00
Chandler Carruth
694d753b09
Another missed memset in std::vector initialization.
...
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@123116 91177308-0d34-0410-b5e6-96231b3b80d8
2011-01-09 11:29:57 +00:00
Chandler Carruth
27a2a13b62
Fix a cut-paste-o so that the sample code is correct for my last note.
...
Also, switch to a more clear 'sink' function with its declaration to
avoid any confusion about 'g'. Thanks for the suggestion Frits.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@123113 91177308-0d34-0410-b5e6-96231b3b80d8
2011-01-09 10:10:59 +00:00
Chandler Carruth
e5ca494ae6
Another missed optimization of trivial vector code.
...
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@123112 91177308-0d34-0410-b5e6-96231b3b80d8
2011-01-09 09:58:36 +00:00
Chandler Carruth
d8723a9b55
Add a note about vector's size-constructor producing dead stores.
...
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@123111 91177308-0d34-0410-b5e6-96231b3b80d8
2011-01-09 09:58:33 +00:00
Chandler Carruth
75fbd3793f
Add a note about a missed memset optimization from std::fill.
...
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@123103 91177308-0d34-0410-b5e6-96231b3b80d8
2011-01-09 01:32:55 +00:00
Benjamin Kramer
eaff66a895
Revert 122959, it needs more thought. Add it back to README.txt with additional notes.
...
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@123030 91177308-0d34-0410-b5e6-96231b3b80d8
2011-01-07 20:42:20 +00:00
Chris Lattner
01cdc2016d
With Benjamin's recent amazing patches, we should be able to do even better things :)
...
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@122978 91177308-0d34-0410-b5e6-96231b3b80d8
2011-01-06 22:25:00 +00:00
Benjamin Kramer
fa36680076
Add a note from llvmdev, this time with more info.
...
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@122966 91177308-0d34-0410-b5e6-96231b3b80d8
2011-01-06 17:35:50 +00:00
Benjamin Kramer
7d9f51f4b5
EarlyCSE does this now (and GVN always did it).
...
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@122960 91177308-0d34-0410-b5e6-96231b3b80d8
2011-01-06 13:19:46 +00:00
Benjamin Kramer
240d42d185
InstCombine: If we call llvm.objectsize on a malloc call we can replace it with the size passed to malloc.
...
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@122959 91177308-0d34-0410-b5e6-96231b3b80d8
2011-01-06 13:11:05 +00:00
Chris Lattner
cce240d26b
add a note about object size from drystone, add a poorly optimized loop from 179.art.
...
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@122954 91177308-0d34-0410-b5e6-96231b3b80d8
2011-01-06 07:41:22 +00:00
Chris Lattner
c1853e4a03
add a trivial instcombine missed in Dhrystone
...
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@122953 91177308-0d34-0410-b5e6-96231b3b80d8
2011-01-06 07:09:23 +00:00
Chris Lattner
527b47d189
update a bunch of entries.
...
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@122700 91177308-0d34-0410-b5e6-96231b3b80d8
2011-01-02 18:31:38 +00:00
Chris Lattner
cf078f2b20
Allow loop-idiom to run on multiple BB loops, but still only scan the loop
...
header for now for memset/memcpy opportunities. It turns out that loop-rotate
is successfully rotating loops, but *DOESN'T MERGE THE BLOCKS*, turning "for
loops" into 2 basic block loops that loop-idiom was ignoring.
With this fix, we form many *many* more memcpy and memsets than before, including
on the "history" loops in the viterbi benchmark, which look like this:
for (j=0; j<MAX_history; ++j) {
history_new[i][j+1] = history[2*i][j];
}
Transforming these loops into memcpy's speeds up the viterbi benchmark from
11.98s to 3.55s on my machine. Woo.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@122685 91177308-0d34-0410-b5e6-96231b3b80d8
2011-01-02 07:58:36 +00:00
Chris Lattner
15df04472a
a missed __builtin_object_size case.
...
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@122676 91177308-0d34-0410-b5e6-96231b3b80d8
2011-01-01 22:57:31 +00:00
Chris Lattner
9c8fb9e820
various updates.
...
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@122675 91177308-0d34-0410-b5e6-96231b3b80d8
2011-01-01 22:52:11 +00:00
Duncan Sands
124708d9b4
Revert commit 122654 at the request of Chris, who reckons that instsimplify
...
is the wrong hammer for this nail, and is probably right.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@122661 91177308-0d34-0410-b5e6-96231b3b80d8
2011-01-01 20:08:02 +00:00