diff options
| author | Nick Lewycky <nicholas@mxc.ca> | 2011-01-22 22:06:21 +0000 |
|---|---|---|
| committer | Nick Lewycky <nicholas@mxc.ca> | 2011-01-22 22:06:21 +0000 |
| commit | 9b8d2c26bce15d47a54718a50b44dd0a65eb88f4 (patch) | |
| tree | b65faf512a3f5705bd4324466bd1ac5a680cb3d5 /lib/Analysis/ScalarEvolution.cpp | |
| parent | 7ea118de46ec81a139e5e56cbcefd5936593a8db (diff) | |
Have SCEV turn sext(x) into zext(x) when x is s>= 0. This applies many times in
"make check" alone.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@124046 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'lib/Analysis/ScalarEvolution.cpp')
| -rw-r--r-- | lib/Analysis/ScalarEvolution.cpp | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/lib/Analysis/ScalarEvolution.cpp b/lib/Analysis/ScalarEvolution.cpp index 424f74427b..63602ffaa7 100644 --- a/lib/Analysis/ScalarEvolution.cpp +++ b/lib/Analysis/ScalarEvolution.cpp @@ -1035,6 +1035,10 @@ const SCEV *ScalarEvolution::getSignExtendExpr(const SCEV *Op, void *IP = 0; if (const SCEV *S = UniqueSCEVs.FindNodeOrInsertPos(ID, IP)) return S; + // If the input value is provably positive, build a zext instead. + if (isKnownNonNegative(Op)) + return getZeroExtendExpr(Op, Ty); + // If the input value is a chrec scev, and we can prove that the value // did not overflow the old, smaller, value, we can sign extend all of the // operands (often constants). This allows analysis of something like |