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Diffstat (limited to 'lib/Target/PowerPC/README_ALTIVEC.txt')
| -rw-r--r-- | lib/Target/PowerPC/README_ALTIVEC.txt | 9 |
1 files changed, 9 insertions, 0 deletions
diff --git a/lib/Target/PowerPC/README_ALTIVEC.txt b/lib/Target/PowerPC/README_ALTIVEC.txt index 143804da07..461b4123c7 100644 --- a/lib/Target/PowerPC/README_ALTIVEC.txt +++ b/lib/Target/PowerPC/README_ALTIVEC.txt @@ -177,3 +177,12 @@ which prevents the vnot pattern from matching. //===----------------------------------------------------------------------===// + +An alternative to the store/store/load approach for illegal insert element +lowering would be: + +1. store element to any ol' slot +2. lvx the slot +3. lvsl 0; splat index; vcmpeq to generate a select mask +4. lvsl slot + x; vperm to rotate result into correct slot +5. vsel result together. |