Benjamin Kramer
3e4106105b
Remove some obsolete README items, add a new one off the top of my head.
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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@122495 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-23 15:07:02 +00:00
Benjamin Kramer
e915ff30cd
X86: Lower a select directly to a setcc_carry if possible.
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int test(unsigned long a, unsigned long b) { return -(a < b); }
compiles to
_test: ## @test
cmpq %rsi, %rdi ## encoding: [0x48,0x39,0xf7]
sbbl %eax, %eax ## encoding: [0x19,0xc0]
ret ## encoding: [0xc3]
instead of
_test: ## @test
xorl %ecx, %ecx ## encoding: [0x31,0xc9]
cmpq %rsi, %rdi ## encoding: [0x48,0x39,0xf7]
movl $-1, %eax ## encoding: [0xb8,0xff,0xff,0xff,0xff]
cmovael %ecx, %eax ## encoding: [0x0f,0x43,0xc1]
ret ## encoding: [0xc3]
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@122451 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-22 23:09:28 +00:00
Benjamin Kramer
20e3b4b380
Factor the (x & 2^n) ? 2^m : 0 instcombine into its own method and generalize it
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to catch cases where n != m with a shift.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@121608 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-11 09:42:59 +00:00
Evan Cheng
3d2125c9db
Enable sibling call optimization of libcalls which are expanded during
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legalization time. Since at legalization time there is no mapping from
SDNode back to the corresponding LLVM instruction and the return
SDNode is target specific, this requires a target hook to check for
eligibility. Only x86 and ARM support this form of sibcall optimization
right now.
rdar://8707777
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@120501 91177308-0d34-0410-b5e6-96231b3b80d8
2010-11-30 23:55:39 +00:00
Chris Lattner
8bc1e45295
apparently tailcalls are better on darwin/x86-64 than on linux?
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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@119947 91177308-0d34-0410-b5e6-96231b3b80d8
2010-11-21 18:59:20 +00:00
Dan Gohman
24bde5bce1
Don't narrow the load and store in a load+twiddle+store sequence unless
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there are clearly no stores between the load and the store. This fixes
this miscompile reported as PR7833.
This breaks the test/CodeGen/X86/narrow_op-2.ll optimization, which is
safe, but awkward to prove safe. Move it to X86's README.txt.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@112861 91177308-0d34-0410-b5e6-96231b3b80d8
2010-09-02 21:18:42 +00:00
Eli Friedman
5033f64694
A couple of small missed optimizations.
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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@112411 91177308-0d34-0410-b5e6-96231b3b80d8
2010-08-29 05:07:40 +00:00
Eric Christopher
9a9d275dc7
Custom lower the memory barrier instructions and add support
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for lowering without sse2. Add a couple of new testcases.
Fixes a few libgomp tests and latent bugs. Remove a few todos.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@109078 91177308-0d34-0410-b5e6-96231b3b80d8
2010-07-22 02:48:34 +00:00
Eli Friedman
2ad7e433c9
Remove a fixed item, update a couple partially-fixed items.
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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@105375 91177308-0d34-0410-b5e6-96231b3b80d8
2010-06-03 01:01:48 +00:00
Dan Gohman
85e9601862
This is now done.
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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@97450 91177308-0d34-0410-b5e6-96231b3b80d8
2010-03-01 17:43:57 +00:00
Eli Friedman
11d91e80b4
A few missed optimizations; the last one could have a significant impact on
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code with lots of bitfields.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@95809 91177308-0d34-0410-b5e6-96231b3b80d8
2010-02-10 21:26:04 +00:00
Chris Lattner
5350f78323
this is an SSE-specific issue.
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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@93373 91177308-0d34-0410-b5e6-96231b3b80d8
2010-01-13 23:29:11 +00:00
Chris Lattner
689339c50f
X86 if conversion + tail merging issues from PR6032.
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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@93372 91177308-0d34-0410-b5e6-96231b3b80d8
2010-01-13 23:28:40 +00:00
Dan Gohman
3c02c22ef9
Remove some README.txt entries which are now implemented.
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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@92511 91177308-0d34-0410-b5e6-96231b3b80d8
2010-01-04 20:55:05 +00:00
Eli Friedman
1f1b0f748d
A couple minor README updates.
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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@91823 91177308-0d34-0410-b5e6-96231b3b80d8
2009-12-21 08:03:16 +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
Bill Wendling
de020736c0
Note corrected.
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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@85332 91177308-0d34-0410-b5e6-96231b3b80d8
2009-10-27 22:43:24 +00:00
Bill Wendling
d8499c9b7f
Modify note.
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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@85331 91177308-0d34-0410-b5e6-96231b3b80d8
2009-10-27 22:40:45 +00:00
Bill Wendling
1ff2c485e2
Add a note.
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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@85329 91177308-0d34-0410-b5e6-96231b3b80d8
2009-10-27 22:34:43 +00:00
Evan Cheng
7216920791
Add a note.
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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@77584 91177308-0d34-0410-b5e6-96231b3b80d8
2009-07-30 08:56:19 +00:00
Chris Lattner
e3821c79bc
remove a bogus note.
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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@74509 91177308-0d34-0410-b5e6-96231b3b80d8
2009-06-30 05:22:31 +00:00
Chris Lattner
a05ec61684
add a note
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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@74508 91177308-0d34-0410-b5e6-96231b3b80d8
2009-06-30 04:20:46 +00:00
Chris Lattner
b42e20be77
another xform that is target-independent (should be done in instcombine).
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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@73472 91177308-0d34-0410-b5e6-96231b3b80d8
2009-06-16 06:15:56 +00:00
Chris Lattner
d23fffeb16
I think instcombine should unconditionally do this xform.
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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@73471 91177308-0d34-0410-b5e6-96231b3b80d8
2009-06-16 06:11:35 +00:00
Eli Friedman
7161cb1dad
Misc x86 README updates: remove a couple of already-fixed issues,
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add a few suggestions from looking at some assembly code.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@73210 91177308-0d34-0410-b5e6-96231b3b80d8
2009-06-11 23:07:04 +00:00
Chris Lattner
d9b77159d6
add some late optimizations that GCC does. It thinks these are a win
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even on Core2, not just AMD processors which was a surprise to me.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@72396 91177308-0d34-0410-b5e6-96231b3b80d8
2009-05-25 20:28:19 +00:00
Chris Lattner
f9dc644936
we should eventually add -march=atom and the new atom movbe instruction.
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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@72387 91177308-0d34-0410-b5e6-96231b3b80d8
2009-05-25 16:34:44 +00:00
Chris Lattner
d1980a5acd
Move 3 "(add (select cc, 0, c), x) -> (select cc, x, (add, x, c))"
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related transformations out of target-specific dag combine into the
ARM backend. These were added by Evan in r37685 with no testcases
and only seems to help ARM (e.g. test/CodeGen/ARM/select_xform.ll).
Add some simple X86-specific (for now) DAG combines that turn things
like cond ? 8 : 0 -> (zext(cond) << 3). This happens frequently
with the recently added cp constant select optimization, but is a
very general xform. For example, we now compile the second example
in const-select.ll to:
_test:
movsd LCPI2_0, %xmm0
ucomisd 8(%esp), %xmm0
seta %al
movzbl %al, %eax
movl 4(%esp), %ecx
movsbl (%ecx,%eax,4), %eax
ret
instead of:
_test:
movl 4(%esp), %eax
leal 4(%eax), %ecx
movsd LCPI2_0, %xmm0
ucomisd 8(%esp), %xmm0
cmovbe %eax, %ecx
movsbl (%ecx), %eax
ret
This passes multisource and dejagnu.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@66779 91177308-0d34-0410-b5e6-96231b3b80d8
2009-03-12 06:52:53 +00:00
Dan Gohman
3328adda6b
Add more information to the EFLAGS note.
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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@66515 91177308-0d34-0410-b5e6-96231b3b80d8
2009-03-10 00:26:23 +00:00
Dan Gohman
ad93e1e5fc
Add a note about EFLAGS optimization.
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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@66508 91177308-0d34-0410-b5e6-96231b3b80d8
2009-03-09 23:47:02 +00:00
Chris Lattner
ff9dcee534
add a note.
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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@66360 91177308-0d34-0410-b5e6-96231b3b80d8
2009-03-08 03:04:26 +00:00
Chris Lattner
b34487dcba
add a note.
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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@66359 91177308-0d34-0410-b5e6-96231b3b80d8
2009-03-08 01:54:43 +00:00
Chris Lattner
a66878b881
add a horrible note
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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@64719 91177308-0d34-0410-b5e6-96231b3b80d8
2009-02-17 01:16:14 +00:00
Dan Gohman
35188eb54d
MachineLICM now handles these cases.
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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@64620 91177308-0d34-0410-b5e6-96231b3b80d8
2009-02-15 23:24:52 +00:00
Chris Lattner
be685cc72a
add a note.
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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@64093 91177308-0d34-0410-b5e6-96231b3b80d8
2009-02-08 20:44:19 +00:00
Chris Lattner
f96ca79cf3
add a note
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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@60632 91177308-0d34-0410-b5e6-96231b3b80d8
2008-12-06 22:49:05 +00:00
Eli Friedman
91db5271d2
A couple small cleanups, plus a new potential optimization.
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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@60286 91177308-0d34-0410-b5e6-96231b3b80d8
2008-11-30 07:52:27 +00:00
Evan Cheng
86d77337fc
Add a README entry.
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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@59052 91177308-0d34-0410-b5e6-96231b3b80d8
2008-11-11 17:35:52 +00:00
Torok Edwin
61df3b751a
move the note to the correct README
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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
Dan Gohman
97b38270cf
This is done.
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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@57733 91177308-0d34-0410-b5e6-96231b3b80d8
2008-10-17 21:38:40 +00:00
Evan Cheng
b09c25ebf0
This is done.
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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@55348 91177308-0d34-0410-b5e6-96231b3b80d8
2008-08-26 01:13:44 +00:00
Nate Begeman
29681a5385
Remove unnecessary readme entry
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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@53722 91177308-0d34-0410-b5e6-96231b3b80d8
2008-07-17 17:21:14 +00:00
Dan Gohman
2d0d59380a
Add a note about a potential PIC optimization.
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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@52663 91177308-0d34-0410-b5e6-96231b3b80d8
2008-06-24 00:53:07 +00:00
Chris Lattner
88c1baa50c
add a micro optzn.
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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@50681 91177308-0d34-0410-b5e6-96231b3b80d8
2008-05-05 23:19:45 +00:00
Chris Lattner
7d717a0b70
Add an ugly note.
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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@50029 91177308-0d34-0410-b5e6-96231b3b80d8
2008-04-21 04:46:30 +00:00
Evan Cheng
ddf0a06580
New entry.
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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@48912 91177308-0d34-0410-b5e6-96231b3b80d8
2008-03-28 07:07:06 +00:00
Evan Cheng
3d5cd6118d
Remove duplicated entries.
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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@48714 91177308-0d34-0410-b5e6-96231b3b80d8
2008-03-23 22:56:07 +00:00
Christopher Lamb
15cbde3cf6
Fix X86's isTruncateFree to not claim that truncate to i1 is free. This fixes Bill's testcase that failed for r48491.
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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@48542 91177308-0d34-0410-b5e6-96231b3b80d8
2008-03-19 08:30:06 +00:00
Chris Lattner
69a74ab421
Add an issue that is preventing instcombine from doing a simplification.
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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@48356 91177308-0d34-0410-b5e6-96231b3b80d8
2008-03-14 06:00:19 +00:00
Chris Lattner
f658ad10f6
move these to the appropriate file
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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@48054 91177308-0d34-0410-b5e6-96231b3b80d8
2008-03-08 22:28:45 +00:00