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Diffstat (limited to 'docs/ReleaseNotes.html')
| -rw-r--r-- | docs/ReleaseNotes.html | 16 |
1 files changed, 15 insertions, 1 deletions
diff --git a/docs/ReleaseNotes.html b/docs/ReleaseNotes.html index a752e53bca..3ee762a01a 100644 --- a/docs/ReleaseNotes.html +++ b/docs/ReleaseNotes.html @@ -219,7 +219,21 @@ LLVM 2.3 optimizers support a few major enhancements:</p> <ul> -<li>Loop index set splitting on by default: describe me.</li> +<li>Loop index set splitting on by default.<p> +This transformation hoists conditions from loop bodies and reduces loop's +iteration space to improve performance. For example, <p> +<pre> +for (i = LB; i < UB; ++i) + if (i <= NV) + LOOP_BODY +</pre> +is transformed into +<pre> +NUB = min(NV+1, UB) +for (i = LB; i < NUB; ++i) + LOOP_BODY +</pre> +</li> <li>LLVM includes a new <tt>memcpy</tt> optimization pass which optimizes out dead <tt>memcpy</tt> calls, unneeded copies of aggregates, and handles the return slot optimization. The LLVM optimizer now notices long sequences of consequtive |