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| author | Chris Lattner <sabre@nondot.org> | 2006-04-17 17:29:41 +0000 |
|---|---|---|
| committer | Chris Lattner <sabre@nondot.org> | 2006-04-17 17:29:41 +0000 |
| commit | 966083fd1ad5adf801b767bba008ebaf0b9e06fa (patch) | |
| tree | cd817f3b1b7d461ebc3c4efcabe0c454be3a1e5d /lib/Target/PowerPC/README_ALTIVEC.txt | |
| parent | 5001ea1078e300fab8d26d183249522b4c4edd98 (diff) | |
| download | external_llvm-966083fd1ad5adf801b767bba008ebaf0b9e06fa.zip external_llvm-966083fd1ad5adf801b767bba008ebaf0b9e06fa.tar.gz external_llvm-966083fd1ad5adf801b767bba008ebaf0b9e06fa.tar.bz2 | |
add a note
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@27758 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'lib/Target/PowerPC/README_ALTIVEC.txt')
| -rw-r--r-- | lib/Target/PowerPC/README_ALTIVEC.txt | 10 |
1 files changed, 10 insertions, 0 deletions
diff --git a/lib/Target/PowerPC/README_ALTIVEC.txt b/lib/Target/PowerPC/README_ALTIVEC.txt index 5d7ecd5..2887b79 100644 --- a/lib/Target/PowerPC/README_ALTIVEC.txt +++ b/lib/Target/PowerPC/README_ALTIVEC.txt @@ -110,3 +110,13 @@ vec_ste(&destloc,0,vTemp); We can do an arbitrary non-constant value by using lvsr/perm/ste. //===----------------------------------------------------------------------===// + +If we want to tie instruction selection into the scheduler, we can do some +constant formation with different instructions. For example, we can generate +"vsplti -1" with "vcmpequw R,R" and 1,1,1,1 with "vsubcuw R,R", both of which +use different execution units, thus could help scheduling. + +This is probably only reasonable for a post-pass scheduler. + +//===----------------------------------------------------------------------===// + |