| commit | a9dba968259e1bf3c400d2578cda0def65800923 | |
| author | Dan Gohman <gohman@apple.com> | |
| Mon, 27 Apr 2009 20:16:15 +0000 (27 20:16 +0000) | ||
| committer | Dan Gohman <gohman@apple.com> | |
| Mon, 27 Apr 2009 20:16:15 +0000 (27 20:16 +0000) | ||
| tree | 95d2dd1b8018daf6d158d81191912652e7b8e41d | treesnapshot (tar.gz zip) |
| parent | fe9f9c1ae3a9dd8a0ea4ce35944d7779aaac58d2 | commitdiff |
Teach getZeroExtendExpr and getSignExtendExpr to use trip-count
information to simplify [sz]ext({a,+,b}) to {zext(a),+,[zs]ext(b)},
as appropriate.
These functions and the trip count code each call into the other, so
this requires careful handling to avoid infinite recursion. During
the initial trip count computation, conservative SCEVs are used,
which are subsequently discarded once the trip count is actually
known.
Among other benefits, this change lets LSR automatically eliminate
some unnecessary zext-inreg and sext-inreg operation where the
operand is an induction variable.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@70241 91177308-0d34-0410-b5e6-96231b3b80d8
information to simplify [sz]ext({a,+,b}) to {zext(a),+,[zs]ext(b)},
as appropriate.
These functions and the trip count code each call into the other, so
this requires careful handling to avoid infinite recursion. During
the initial trip count computation, conservative SCEVs are used,
which are subsequently discarded once the trip count is actually
known.
Among other benefits, this change lets LSR automatically eliminate
some unnecessary zext-inreg and sext-inreg operation where the
operand is an induction variable.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@70241 91177308-0d34-0410-b5e6-96231b3b80d8
| lib/Analysis/ScalarEvolution.cpp | diffblobblamehistory | |
| test/CodeGen/X86/masked-iv-safe.ll | [new file with mode: 0644] | blob |
| test/CodeGen/X86/masked-iv-unsafe.ll | [new file with mode: 0644] | blob |
| test/Transforms/LoopStrengthReduce/change-compare-stride-trickiness-1.ll | diffblobblamehistory |