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| author | Chris Lattner <sabre@nondot.org> | 2006-09-18 05:36:54 +0000 |
|---|---|---|
| committer | Chris Lattner <sabre@nondot.org> | 2006-09-18 05:36:54 +0000 |
| commit | f73fb88688e5cbc851596d7ad50e1f257048953a (patch) | |
| tree | e16dc195e6baecfecbc134d2c9c2f7bdfc1e283e | |
| parent | e695a3bd32443aa7da9f5d699f2ad763643d0032 (diff) | |
add a note. Our 64-bit shifts are ~30% slower than gcc's
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@30457 91177308-0d34-0410-b5e6-96231b3b80d8
| -rw-r--r-- | lib/Target/X86/README.txt | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/lib/Target/X86/README.txt b/lib/Target/X86/README.txt index 62c8ab1dcc..dd02948f87 100644 --- a/lib/Target/X86/README.txt +++ b/lib/Target/X86/README.txt @@ -59,7 +59,8 @@ One better solution for 1LL << x is: But that requires good 8-bit subreg support. - +64-bit shifts (in general) expand to really bad code. Instead of using +cmovs, we should expand to a conditional branch like GCC produces. //===---------------------------------------------------------------------===// |