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| -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: |