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| author | Chris Lattner <sabre@nondot.org> | 2002-09-23 23:39:43 +0000 |
|---|---|---|
| committer | Chris Lattner <sabre@nondot.org> | 2002-09-23 23:39:43 +0000 |
| commit | d06451f920a8927cd87d0a4af730015365151ffe (patch) | |
| tree | 6a74a7625371a89d8289778e1cf0c6982e3e0847 | |
| parent | a30b70f381e2a7342cdfdee05fba25c1b77a56eb (diff) | |
Optimize away cases like:
%cast109 = cast uint %cast212 to short ; <short> [#uses=1]
%cast214 = cast short %cast109 to uint ; <uint> [#uses=1]
%cast215 = cast uint %cast214 to short ; <short> [#uses=1]
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@3897 91177308-0d34-0410-b5e6-96231b3b80d8
| -rw-r--r-- | lib/Transforms/Scalar/InstructionCombining.cpp | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/lib/Transforms/Scalar/InstructionCombining.cpp b/lib/Transforms/Scalar/InstructionCombining.cpp index 082dc020b0..b60d1fa972 100644 --- a/lib/Transforms/Scalar/InstructionCombining.cpp +++ b/lib/Transforms/Scalar/InstructionCombining.cpp @@ -536,6 +536,12 @@ static inline bool isEliminableCastOfCast(const CastInst &CI, if (SrcSize >= MidSize && MidSize >= DstSize) return true; + // Cases where the source and destination type are the same, but the middle + // type is bigger are noops. + // + if (SrcSize == DstSize && MidSize > SrcSize) + return true; + // If we are monotonically growing, things are more complex. // if (SrcSize <= MidSize && MidSize <= DstSize) { |