From d8499c9b7fae7c5afbb81dc7e7cf957abbafdb54 Mon Sep 17 00:00:00 2001 From: Bill Wendling Date: Tue, 27 Oct 2009 22:40:45 +0000 Subject: [PATCH] Modify note. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@85331 91177308-0d34-0410-b5e6-96231b3b80d8 --- lib/Target/X86/README.txt | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/lib/Target/X86/README.txt b/lib/Target/X86/README.txt index 5967fd55c09..75dde2d28aa 100644 --- a/lib/Target/X86/README.txt +++ b/lib/Target/X86/README.txt @@ -1969,9 +1969,17 @@ LBB1_2: movsbl %al, %eax Better: + movl %esi, %eax orl $-128, %eax andl $-128, %esi testb %dil, %dil cmovns %esi, %eax movsbl %al,%eax + +Best (recognize this as 'b = (b & ~0x80) | (a & 0x80)'): + + andb $-128, %dil + andb $127, %sil + orb %dil, %sil + movsbl %sil, %eax