Commit Graph

240 Commits

Author SHA1 Message Date
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
Duncan Sands
7cf85e74e3 Fix a README item by having InstructionSimplify do a mild form of value
numbering, in which it considers (for example) "%a = add i32 %x, %y" and
"%b = add i32 %x, %y" to be equal because the operands are equal and the
result of the instructions only depends on the values of the operands.
This has almost no effect (it removes 4 instructions from gcc-as-one-file),
and perhaps slows down compilation: I measured a 0.4% slowdown on the large
gcc-as-one-file testcase, but it wasn't statistically significant.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@122654 91177308-0d34-0410-b5e6-96231b3b80d8
2011-01-01 16:12:09 +00:00
Chris Lattner
1dc5db2beb add a note from llvmdev
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@122603 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-28 18:45:02 +00:00
Benjamin Kramer
9d071cbb92 Remove/fix invalid README entries. The well thought out strcpy function doesn't return a pointer to the end of the string.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@122496 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-23 15:32:07 +00:00
Chris Lattner
e5cbdca3bd recognize an unsigned add with overflow idiom into uadd.
This resolves a README entry and technically resolves PR4916,
but we still get poor code for the testcase in that PR because
GVN isn't CSE'ing uadd with add, filed as PR8817.

Previously we got:

_test7:                                 ## @test7
	addq	%rsi, %rdi
	cmpq	%rdi, %rsi
	movl	$42, %eax
	cmovaq	%rsi, %rax
	ret

Now we get:

_test7:                                 ## @test7
	addq	%rsi, %rdi
	movl	$42, %eax
	cmovbq	%rsi, %rax
	ret



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@122182 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-19 19:37:52 +00:00
Chris Lattner
9448184b99 add another overflow idiom
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@121854 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-15 07:28:58 +00:00
Chris Lattner
08859ffa63 add a note about overflow idiom recognition.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@121853 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-15 07:25:55 +00:00
Chris Lattner
ef17f08dbc add a shift/imul missed optimization
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@121850 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-15 07:10:43 +00:00
Chris Lattner
2fc36e19b1 add a note about a SPEC hack that gcc mainline does.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@121849 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-15 06:38:24 +00:00
Chris Lattner
a97c91f014 add a note
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@121656 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-13 00:15:25 +00:00
Benjamin Kramer
2f7228b80c Generalize the and-icmp-select instcombine further by allowing selects of the form
(x & 2^n) ? 2^m+C : C

we can offset both arms by C to get the "(x & 2^n) ? 2^m : 0" form, optimize the
select to a shift and apply the offset afterwards.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@121609 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-11 10:49:22 +00:00
Benjamin Kramer
c21a821e9f The srem -> urem transform is not safe for any divisor that's not a power of two.
E.g. -5 % 5 is 0 with srem and 1 with urem.

Also addresses Frits van Bommel's comments.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@120049 91177308-0d34-0410-b5e6-96231b3b80d8
2010-11-23 20:33:57 +00:00
Benjamin Kramer
b70ebd2aa3 InstCombine: Reduce "X shift (A srem B)" to "X shift (A urem B)" iff B is positive.
This allows to transform the rem in "1 << ((int)x % 8);" to an and.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@120028 91177308-0d34-0410-b5e6-96231b3b80d8
2010-11-23 18:52:42 +00:00
Benjamin Kramer
93f8455d73 InstCombine: Implement X - A*-B -> X + A*B.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@119984 91177308-0d34-0410-b5e6-96231b3b80d8
2010-11-22 20:31:27 +00:00
Benjamin Kramer
ce750f0332 Implement the "if (X == 6 || X == 4)" -> "if ((X|2) == 6)" optimization.
This currently only catches the most basic case, a two-case switch, but can be
extended later.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@119964 91177308-0d34-0410-b5e6-96231b3b80d8
2010-11-22 09:45:38 +00:00
Chris Lattner
3e41106de4 add some random notes.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@119925 91177308-0d34-0410-b5e6-96231b3b80d8
2010-11-21 07:05:31 +00:00
Chris Lattner
75d8f599e7 optimize:
void a(int x) { if (((1<<x)&8)==0) b(); }

into "x != 3", which occurs over 100 times in 403.gcc but in no
other program in llvm-test.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@119922 91177308-0d34-0410-b5e6-96231b3b80d8
2010-11-21 06:44:42 +00:00
Chris Lattner
79a980ad85 tail calls on x86 are implemented.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@119920 91177308-0d34-0410-b5e6-96231b3b80d8
2010-11-21 06:10:27 +00:00
Chris Lattner
af510f16ec add a note
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@118806 91177308-0d34-0410-b5e6-96231b3b80d8
2010-11-11 18:23:57 +00:00
Chris Lattner
1e68fdb946 add pr#
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@118797 91177308-0d34-0410-b5e6-96231b3b80d8
2010-11-11 17:17:56 +00:00
Chris Lattner
274191fa70 add a case we fail to devirt.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@118608 91177308-0d34-0410-b5e6-96231b3b80d8
2010-11-09 19:37:28 +00:00
Duncan Sands
1ac7c9979a Fix a README item: when doing a comparison with the result
of a select instruction, see if doing the compare with the
true and false values of the select gives the same result.
If so, that can be used as the value of the comparison.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@118378 91177308-0d34-0410-b5e6-96231b3b80d8
2010-11-07 16:12:23 +00:00
Benjamin Kramer
019e378754 Add a note.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@118337 91177308-0d34-0410-b5e6-96231b3b80d8
2010-11-06 10:37:16 +00:00
Benjamin Kramer
9510a2538b Add constant folding for strspn and strcspn to SimplifyLibCalls.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@115116 91177308-0d34-0410-b5e6-96231b3b80d8
2010-09-30 00:58:35 +00:00