diff options
author | Chris Lattner <sabre@nondot.org> | 2006-09-21 06:14:54 +0000 |
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committer | Chris Lattner <sabre@nondot.org> | 2006-09-21 06:14:54 +0000 |
commit | b13f83eb23ad08cdee76b1ef6c2ae85782dd2dd4 (patch) | |
tree | 8b7f2826bf0446b782256502794175ce5c0f42e7 | |
parent | 111c22824115ed77a8f14e555c10880d07a45eb4 (diff) |
implemented
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@30559 91177308-0d34-0410-b5e6-96231b3b80d8
-rw-r--r-- | lib/Target/X86/README.txt | 35 |
1 files changed, 0 insertions, 35 deletions
diff --git a/lib/Target/X86/README.txt b/lib/Target/X86/README.txt index cc689c4a85..4a0be7bbb0 100644 --- a/lib/Target/X86/README.txt +++ b/lib/Target/X86/README.txt @@ -642,41 +642,6 @@ sequence)? //===---------------------------------------------------------------------===// -Compile: -int %test(ulong *%tmp) { - %tmp = load ulong* %tmp ; <ulong> [#uses=1] - %tmp.mask = shr ulong %tmp, ubyte 50 ; <ulong> [#uses=1] - %tmp.mask = cast ulong %tmp.mask to ubyte - %tmp2 = and ubyte %tmp.mask, 3 ; <ubyte> [#uses=1] - %tmp2 = cast ubyte %tmp2 to int ; <int> [#uses=1] - ret int %tmp2 -} - -to: - -_test: - movl 4(%esp), %eax - movl 4(%eax), %eax - shrl $18, %eax - andl $3, %eax - ret - -instead of: - -_test: - movl 4(%esp), %eax - movl 4(%eax), %eax - shrl $18, %eax - # TRUNCATE movb %al, %al - andb $3, %al - movzbl %al, %eax - ret - -This saves a movzbl, and saves a truncate if it doesn't get coallesced right. -This is a simple DAGCombine to propagate the zext through the and. - -//===---------------------------------------------------------------------===// - GCC's ix86_expand_int_movcc function (in i386.c) has a ton of interesting simplifications for integer "x cmp y ? a : b". For example, instead of: |