Commit Graph

4 Commits

Author SHA1 Message Date
Evan Cheng
aaf414c92c Favors generating "not" over "xor -1". For example.
unsigned test(unsigned a) {
  return ~a;
}
llvm used to generate:
movl    $4294967295, %eax
xorl    4(%esp), %eax

Now it generates:
movl      4(%esp), %eax
notl      %eax

It's 3 bytes shorter.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@62661 91177308-0d34-0410-b5e6-96231b3b80d8
2009-01-21 02:09:05 +00:00
Dan Gohman
a779a9899a Add AsmPrinter support for emitting a directive to declare that
the code being generated does not require an executable stack.

Also, add target-specific code to make use of this on Linux
on x86. 


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@50634 91177308-0d34-0410-b5e6-96231b3b80d8
2008-05-05 00:28:39 +00:00
Chris Lattner
eeb939accb fix this testcase to pass and remove a duplicate instance of itself.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@49281 91177308-0d34-0410-b5e6-96231b3b80d8
2008-04-06 21:39:17 +00:00
Torok Edwin
4fea2e982d Prefer to expand mask for xor to -1, so we have a chance to turn it into a not.
If it cannot be expanded, it will keep the old behaviour and try to shrink the constant.
Part of enhancement for PR2191.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@49280 91177308-0d34-0410-b5e6-96231b3b80d8
2008-04-06 21:23:02 +00:00