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| author | Chris Lattner <sabre@nondot.org> | 2006-09-13 03:54:54 +0000 |
|---|---|---|
| committer | Chris Lattner <sabre@nondot.org> | 2006-09-13 03:54:54 +0000 |
| commit | 95af34e33f9918dc8a399f8414ce6a9673bd5ffb (patch) | |
| tree | 0555baba029f5dfeca63234a36dd3f29907cb9e3 | |
| parent | 79980b07dab50da1a8f572f9504674bfa853d484 (diff) | |
new note
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@30285 91177308-0d34-0410-b5e6-96231b3b80d8
| -rw-r--r-- | lib/Target/X86/README.txt | 13 |
1 files changed, 13 insertions, 0 deletions
diff --git a/lib/Target/X86/README.txt b/lib/Target/X86/README.txt index 8994569ea9..5e2ab199ad 100644 --- a/lib/Target/X86/README.txt +++ b/lib/Target/X86/README.txt @@ -45,6 +45,19 @@ http://gcc.gnu.org/ml/gcc-patches/2004-09/msg01136.html Another useful one would be ~0ULL >> X and ~0ULL << X. +One better solution for 1LL << x is: + xorl %eax, %eax + xorl %edx, %edx + testb $32, %cl + sete %al + setne %dl + sall %cl, %eax + sall %cl, %edx + +But that requires good 8-bit subreg support. + + + //===---------------------------------------------------------------------===// Compile this: |