diff options
| author | Chris Lattner <sabre@nondot.org> | 2010-01-23 18:42:37 +0000 |
|---|---|---|
| committer | Chris Lattner <sabre@nondot.org> | 2010-01-23 18:42:37 +0000 |
| commit | a9cf5b3cc9082acee5b6e30e989a667fed286b05 (patch) | |
| tree | 4e4e777c5576255d0f9daf2d0896d747a02df8a2 /lib/Target/PowerPC/README.txt | |
| parent | aa306c2cc1945b3e68c8cf2925e9b1197126d54c (diff) | |
| download | llvm-a9cf5b3cc9082acee5b6e30e989a667fed286b05.tar.gz llvm-a9cf5b3cc9082acee5b6e30e989a667fed286b05.tar.bz2 llvm-a9cf5b3cc9082acee5b6e30e989a667fed286b05.tar.xz | |
add a note
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@94317 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'lib/Target/PowerPC/README.txt')
| -rw-r--r-- | lib/Target/PowerPC/README.txt | 29 |
1 files changed, 29 insertions, 0 deletions
diff --git a/lib/Target/PowerPC/README.txt b/lib/Target/PowerPC/README.txt index 060d6a5c5c..a243543cd4 100644 --- a/lib/Target/PowerPC/README.txt +++ b/lib/Target/PowerPC/README.txt @@ -635,6 +635,35 @@ This sort of thing occurs a lot due to globalopt. ===-------------------------------------------------------------------------=== +We compile: + +define i32 @bar(i32 %x) nounwind readnone ssp { +entry: + %0 = icmp eq i32 %x, 0 ; <i1> [#uses=1] + %neg = select i1 %0, i32 -1, i32 0 ; <i32> [#uses=1] + ret i32 %neg +} + +to: + +_bar: + cmplwi cr0, r3, 0 + li r3, -1 + beq cr0, LBB1_2 +; BB#1: ; %entry + li r3, 0 +LBB1_2: ; %entry + blr + +it would be much better to produce: + +_bar: + addic r3,r3,-1 + subfe r3,r3,r3 + blr + +===-------------------------------------------------------------------------=== + We currently compile 32-bit bswap: declare i32 @llvm.bswap.i32(i32 %A) |