Commit Graph

19 Commits

Author SHA1 Message Date
Shuxin Yang
00fab97c01 fix a typo
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@169345 91177308-0d34-0410-b5e6-96231b3b80d8
2012-12-05 00:33:16 +00:00
Shuxin Yang
a09e18fcfa For rdar://12329730, last piece.
This change attempts to simplify (X^Y) -> X or Y in the user's context if we know that
only bits from X or Y are demanded.

  A minimized case is provided bellow. This change will simplify "t>>16" into "var1 >>16".

  =============================================================
  unsigned foo (unsigned val1, unsigned val2) {
    unsigned t = val1 ^ 1234;
    return (t >> 16) | t; // NOTE: t is used more than once.
  }
  =============================================================

  Note that if the "t" were used only once, the expression would be finally optimized as well.
However, with with this change, the optimization will take place earlier.

  Reviewed by Nadav, Thanks a lot!


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@169317 91177308-0d34-0410-b5e6-96231b3b80d8
2012-12-04 22:15:32 +00:00
Shuxin Yang
b30e256993 rdar://12329730 (defect 2)
Enhancement to InstCombine. Try to catch this opportunity:
  
 ---------------------------------------------------------------
 ((X^C1) >> C2) ^ C3  => (X>>C2) ^ ((C1>>C2)^C3)
  where the subexpression "X ^ C1" has more than one uses, and
  "(X^C1) >> C2" has single use. 
 ---------------------------------------------------------------- 

 Reviewed by Nadav (with minor change per his request).


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@168615 91177308-0d34-0410-b5e6-96231b3b80d8
2012-11-26 21:44:25 +00:00
Owen Anderson
2c5f19db2e Re-apply r113679, which was reverted in r113720, which added a paid of new instcombine transforms
to expose greater opportunities for store narrowing in codegen.  This patch fixes a potential
infinite loop in instcombine caused by one of the introduced transforms being overly aggressive.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@113763 91177308-0d34-0410-b5e6-96231b3b80d8
2010-09-13 17:59:27 +00:00
Eric Christopher
298c45e845 Revert 113679, it was causing an infinite loop in a testcase that I've sent
on to Owen.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@113720 91177308-0d34-0410-b5e6-96231b3b80d8
2010-09-12 06:09:23 +00:00
Owen Anderson
26c5663283 Invert and-of-or into or-of-and when doing so would allow us to clear bits of the and's mask.
This can result in increased opportunities for store narrowing in code generation.  Update a number of
tests for this change.  This fixes <rdar://problem/8285027>.

Additionally, because this inverts the order of ors and ands, some patterns for optimizing or-of-and-of-or
no longer fire in instances where they did originally.  Add a simple transform which recaptures most of these
opportunities: if we have an or-of-constant-or and have failed to fold away the inner or, commute the order 
of the two ors, to give the non-constant or a chance for simplification instead.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@113679 91177308-0d34-0410-b5e6-96231b3b80d8
2010-09-11 05:48:06 +00:00
Benjamin Kramer
e2d07b5208 Revert r108141 again, sigh.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@108148 91177308-0d34-0410-b5e6-96231b3b80d8
2010-07-12 14:42:04 +00:00
Benjamin Kramer
98a8206e58 Reapply 108136 with an ugly pasto fixed.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@108141 91177308-0d34-0410-b5e6-96231b3b80d8
2010-07-12 13:44:00 +00:00
Benjamin Kramer
0cc4ed1ca5 Revert r108136 until I figure out why it broke selfhost.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@108139 91177308-0d34-0410-b5e6-96231b3b80d8
2010-07-12 12:35:49 +00:00
Benjamin Kramer
4fc719e607 instcombine: fold (x & y) | (~x & z) and (x & y) ^ (~x & z) into ((y ^ z) & x) ^ z which is one instruction shorter. (PR6773)
before:
  %and = and i32 %y, %x
  %neg = xor i32 %x, -1
  %and4 = and i32 %z, %neg
  %xor = xor i32 %and4, %and

after:
  %xor1 = xor i32 %z, %y
  %and2 = and i32 %xor1, %x
  %xor = xor i32 %and2, %z


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@108136 91177308-0d34-0410-b5e6-96231b3b80d8
2010-07-12 11:54:45 +00:00
Bill Wendling
7d9f2b93a3 This test case:
long test(long x) { return (x & 123124) | 3; }

Currently compiles to:

_test:
        orl     $3, %edi
        movq    %rdi, %rax
        andq    $123127, %rax
        ret

This is because instruction and DAG combiners canonicalize

  (or (and x, C), D) -> (and (or, D), (C | D))

However, this is only profitable if (C & D) != 0. It gets in the way of the
3-addressification because the input bits are known to be zero.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@97616 91177308-0d34-0410-b5e6-96231b3b80d8
2010-03-03 00:35:56 +00:00
Chris Lattner
c0404b3715 optimize ~(~X >>s Y) --> (X >>s Y), patch by Edmund Grimley
Evans!


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@93884 91177308-0d34-0410-b5e6-96231b3b80d8
2010-01-19 18:16:19 +00:00
Chris Lattner
d088314998 teach instcombine to simplify xor's harder, catching the
new testcase.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@83799 91177308-0d34-0410-b5e6-96231b3b80d8
2009-10-11 22:22:13 +00:00
Chris Lattner
833f0cc57f convert xor2 to filecheck, merge in a random regtest
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@83796 91177308-0d34-0410-b5e6-96231b3b80d8
2009-10-11 21:42:08 +00:00
Dan Gohman
f2f6ce65b7 Change tests from "opt %s" to "opt < %s" so that opt doesn't see the
input filename so that opt doesn't print the input filename in the
output so that grep lines in the tests don't unintentionally match
strings in the input filename.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@81537 91177308-0d34-0410-b5e6-96231b3b80d8
2009-09-11 18:01:28 +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
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
Chris Lattner
08a3fbe42e new testcase for PR1253
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@35611 91177308-0d34-0410-b5e6-96231b3b80d8
2007-04-03 01:45:32 +00:00