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| author | Shuxin Yang <shuxin.llvm@gmail.com> | 2012-12-04 00:04:54 +0000 |
|---|---|---|
| committer | Shuxin Yang <shuxin.llvm@gmail.com> | 2012-12-04 00:04:54 +0000 |
| commit | c811976b0400257511f2a255ec70538c3614f85e (patch) | |
| tree | 1f1290d99a7f23d2c7d49d1e7c8a290589361ae8 /lib/Transforms/InstCombine/InstCombine.h | |
| parent | fc6374439edf2f74da4026f4cea8e341d092be5c (diff) | |
rdar://12329730 (2nd part)
This change tries to simmplify E1 = " X >> C1 << C2" into :
- E2 = "X << (C2 - C1)" if C2 > C1, or
- E2 = "X >> (C1 - C2)" if C1 > C2, or
- E2 = X if C1 == C2.
Reviewed by Nadav. Thanks!
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@169182 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'lib/Transforms/InstCombine/InstCombine.h')
| -rw-r--r-- | lib/Transforms/InstCombine/InstCombine.h | 5 |
1 files changed, 5 insertions, 0 deletions
diff --git a/lib/Transforms/InstCombine/InstCombine.h b/lib/Transforms/InstCombine/InstCombine.h index 90637a9d7b..ff5eeb6192 100644 --- a/lib/Transforms/InstCombine/InstCombine.h +++ b/lib/Transforms/InstCombine/InstCombine.h @@ -327,6 +327,11 @@ private: bool SimplifyDemandedBits(Use &U, APInt DemandedMask, APInt& KnownZero, APInt& KnownOne, unsigned Depth=0); + /// Helper routine of SimplifyDemandedUseBits. It tries to simplify demanded + /// bit for "r1 = shr x, c1; r2 = shl r1, c2" instruction sequence. + Value *SimplifyShrShlDemandedBits(Instruction *Lsr, Instruction *Sftl, + APInt DemandedMask, APInt &KnownZero, + APInt &KnownOne); /// SimplifyDemandedInstructionBits - Inst is an integer instruction that /// SimplifyDemandedBits knows about. See if the instruction has any |