47 Commits

Author SHA1 Message Date
Nick Lewycky
148fd55ef3 Teach instcombine all sorts of great stuff about shifts that have exact, nuw or
nsw bits on them.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@147528 91177308-0d34-0410-b5e6-96231b3b80d8
2012-01-04 09:28:29 +00:00
Nick Lewycky
57ed0948b8 Make use of the exact bit when optimizing '(X >>exact 3) << 1' to eliminate the
'and' that would zero out the trailing bits, and to produce an exact shift
ourselves.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@147391 91177308-0d34-0410-b5e6-96231b3b80d8
2011-12-31 21:30:22 +00:00
Eli Friedman
ef71597242 Make sure to correctly clear the exact/nuw/nsw flags off of shifts when they are combined together. <rdar://problem/9859829>
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@136435 91177308-0d34-0410-b5e6-96231b3b80d8
2011-07-29 00:18:19 +00:00
Chris Lattner
05cd886561 Transform any logical shift of a power of two into an exact/NUW shift when
in a known-non-zero context.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@131887 91177308-0d34-0410-b5e6-96231b3b80d8
2011-05-23 00:21:50 +00:00
Benjamin Kramer
c2e31c1461 InstCombine: turn (C1 << A) << C2) into (C1 << C2) << A)
Fixes PR9809.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@130485 91177308-0d34-0410-b5e6-96231b3b80d8
2011-04-29 08:15:41 +00:00
Chris Lattner
7a6aa1a391 Enhance a bunch of transformations in instcombine to start generating
exact/nsw/nuw shifts and have instcombine infer them when it can prove
that the relevant properties are true for a given shift without them.

Also, a variety of refactoring to use the new patternmatch logic thrown
in for good luck.  I believe that this takes care of a bunch of related
code quality issues attached to PR8862.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@125267 91177308-0d34-0410-b5e6-96231b3b80d8
2011-02-10 05:36:31 +00:00
Duncan Sands
c43cee3fbb Move some shift transforms out of instcombine and into InstructionSimplify.
While there, I noticed that the transform "undef >>a X -> undef" was wrong.
For example if X is 2 then the top two bits must be equal, so the result can
not be anything.  I fixed this in the constant folder as well.  Also, I made
the transform for "X << undef" stronger: it now folds to undef always, even
though X might be zero.  This is in accordance with the LangRef, but I must
admit that it is fairly aggressive.  Also, I added "i32 X << 32 -> undef"
following the LangRef and the constant folder, likewise fairly aggressive.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@123417 91177308-0d34-0410-b5e6-96231b3b80d8
2011-01-14 00:37:45 +00:00
Owen Anderson
ec3953ff95 When determining if we can fold (x >> C1) << C2, the bits that we need to verify are zero
are not the low bits of x, but the bits that WILL be the low bits after the operation completes.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@122529 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-23 23:56:24 +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
Chris Lattner
11493aa471 tidy up test.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@112321 91177308-0d34-0410-b5e6-96231b3b80d8
2010-08-27 23:15:21 +00:00
Chris Lattner
4ece577019 Enhance the shift propagator to handle the case when you have:
A = shl x, 42
...
B = lshr ..., 38

which can be transformed into:
A = shl x, 4
...

iff we can prove that the would-be-shifted-in bits
are already zero.  This eliminates two shifts in the testcase
and allows eliminate of the whole i128 chain in the real example.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@112314 91177308-0d34-0410-b5e6-96231b3b80d8
2010-08-27 22:53:44 +00:00
Chris Lattner
29cc0b3660 Implement a pretty general logical shift propagation
framework, which is good at ripping through bitfield
operations.  This generalize a bunch of the existing
xforms that instcombine does, such as 
  (x << c) >> c -> and
to handle intermediate logical nodes.  This is useful for
ripping up the "promote to large integer" code produced by
SRoA.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@112304 91177308-0d34-0410-b5e6-96231b3b80d8
2010-08-27 22:24:38 +00:00
Chris Lattner
d07ad66791 merge and filecheckize test
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@112289 91177308-0d34-0410-b5e6-96231b3b80d8
2010-08-27 20:44:45 +00:00
Chris Lattner
7673290a96 merge two tests
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@112288 91177308-0d34-0410-b5e6-96231b3b80d8
2010-08-27 20:42:10 +00:00
Chris Lattner
90d4f3a077 merge test into shift.ll, this also eliminates awful grepping on -stats output
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@83802 91177308-0d34-0410-b5e6-96231b3b80d8
2009-10-11 22:39:58 +00:00
Chris Lattner
490ff6310a convert to filecheck.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@83801 91177308-0d34-0410-b5e6-96231b3b80d8
2009-10-11 22:36:59 +00:00
Dan Gohman
3e054fe9ef Use opt -S instead of piping bitcode output through llvm-dis.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@81257 91177308-0d34-0410-b5e6-96231b3b80d8
2009-09-08 22:34:10 +00:00
Dan Gohman
b1e1e82c54 Change these tests to feed the assembly files to opt directly, instead
of using llvm-as, now that opt supports this.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@81226 91177308-0d34-0410-b5e6-96231b3b80d8
2009-09-08 16:50:01 +00:00
Chris Lattner
4f9797d683 two changes:
1. Make instcombine always canonicalize trunc x to i1 into an icmp(x&1).  This 
   exposes the AND to other instcombine xforms and is more of what the code
   generator expects.
2. Rewrite the remaining trunc pattern match to use 'match', which 
   simplifies it a lot.
   


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@67635 91177308-0d34-0410-b5e6-96231b3b80d8
2009-03-24 18:15:30 +00:00
Tanya Lattner
76806b6a43 Remove llvm-upgrade and update tests.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@48103 91177308-0d34-0410-b5e6-96231b3b80d8
2008-03-09 08:16:40 +00:00
Tanya Lattner
ec9a35a6f9 Remove llvm-upgrade and update test cases.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@47793 91177308-0d34-0410-b5e6-96231b3b80d8
2008-03-01 09:15:35 +00:00
Reid Spencer
2b544beda3 For PR1319:
Upgrade tests to work with new llvm.exp version of llvm_runtest.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@36013 91177308-0d34-0410-b5e6-96231b3b80d8
2007-04-14 20:13:02 +00:00
Reid Spencer
69ccadd753 Use the llvm-upgrade program to upgrade llvm assembly.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@32115 91177308-0d34-0410-b5e6-96231b3b80d8
2006-12-02 04:23:10 +00:00
Chris Lattner
82b98a0646 Make these tests fail if opt crashes.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@26127 91177308-0d34-0410-b5e6-96231b3b80d8
2006-02-12 01:32:58 +00:00
Chris Lattner
6c7fbb8503 A case that instcombine is not catching.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@25127 91177308-0d34-0410-b5e6-96231b3b80d8
2006-01-06 07:48:28 +00:00
Chris Lattner
ab4ea6e980 new testcase
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@23380 91177308-0d34-0410-b5e6-96231b3b80d8
2005-09-18 05:10:39 +00:00
Chris Lattner
a9c83c73da new testcase
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@21774 91177308-0d34-0410-b5e6-96231b3b80d8
2005-05-08 17:31:24 +00:00
Chris Lattner
1b50d062c8 new testcase
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@21714 91177308-0d34-0410-b5e6-96231b3b80d8
2005-05-06 04:11:32 +00:00
Chris Lattner
59359f1e84 New testcases
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@16547 91177308-0d34-0410-b5e6-96231b3b80d8
2004-09-28 18:18:35 +00:00
Chris Lattner
907c7c7dd1 Testcases for rev 250 of InstructionCombining.cpp
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@16522 91177308-0d34-0410-b5e6-96231b3b80d8
2004-09-27 16:21:26 +00:00
Chris Lattner
256b7a452b New testcase
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@13739 91177308-0d34-0410-b5e6-96231b3b80d8
2004-05-25 06:30:49 +00:00
Chris Lattner
1c48527330 Testcase to make sure we can apply the shift to the operands of the select,
eliminating the shifts


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@12801 91177308-0d34-0410-b5e6-96231b3b80d8
2004-04-09 23:47:24 +00:00
Misha Brukman
e78760e179 Renamed as' => llvm-as', dis' => llvm-dis', link' => llvm-link'.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@8558 91177308-0d34-0410-b5e6-96231b3b80d8
2003-09-16 15:29:54 +00:00
Chris Lattner
ab04c365b8 Update test to represent new cannonicalization rules for multiplies
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@7804 91177308-0d34-0410-b5e6-96231b3b80d8
2003-08-13 04:20:06 +00:00
Chris Lattner
dc20a3e7d3 Right, instcombine cannot remove ((X >> C) << C) if it's signed.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@7790 91177308-0d34-0410-b5e6-96231b3b80d8
2003-08-12 21:22:51 +00:00
Chris Lattner
b310196abc New testcases
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@7789 91177308-0d34-0410-b5e6-96231b3b80d8
2003-08-12 21:20:49 +00:00
Chris Lattner
709ad40dc8 New testcases for signed shifts
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@7294 91177308-0d34-0410-b5e6-96231b3b80d8
2003-07-24 18:38:09 +00:00
Chris Lattner
060c1f816c Remove usage of grep-not script
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@6966 91177308-0d34-0410-b5e6-96231b3b80d8
2003-06-28 23:32:04 +00:00
Chris Lattner
c6cab24151 Convert scripts from using explicit control flow to use the new grep-not script
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@6955 91177308-0d34-0410-b5e6-96231b3b80d8
2003-06-28 22:44:42 +00:00
Chris Lattner
c232870b6f Add a bunch of new tests
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@5730 91177308-0d34-0410-b5e6-96231b3b80d8
2003-03-10 19:16:20 +00:00
Chris Lattner
a66e2fa195 Modernize testcase
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@5726 91177308-0d34-0410-b5e6-96231b3b80d8
2003-03-10 18:20:53 +00:00
Chris Lattner
af1b4ad24c Add new testcase for arithmetic shr of -1
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@4069 91177308-0d34-0410-b5e6-96231b3b80d8
2002-10-08 16:10:35 +00:00
Chris Lattner
dabb94adc1 Check for cannonicalization of shl X, 1 -> add X, X
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@3670 91177308-0d34-0410-b5e6-96231b3b80d8
2002-09-10 23:03:10 +00:00
Chris Lattner
4a6e4b30b4 These tests should not run -dce pass to cleanup instcombine.
If instcombine is making dead instructions, ALL that should be used is -die


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@3221 91177308-0d34-0410-b5e6-96231b3b80d8
2002-08-02 19:27:58 +00:00
Chris Lattner
79a31b1782 Fix testcase, the 'shift out all bits' doesn't apply to signed types.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@2482 91177308-0d34-0410-b5e6-96231b3b80d8
2002-05-06 16:11:31 +00:00
Chris Lattner
33a90b18e0 New testcases so I don't forget about these algebraic simplifications
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@2479 91177308-0d34-0410-b5e6-96231b3b80d8
2002-05-06 05:43:36 +00:00