diff options
Diffstat (limited to 'llvm')
| -rw-r--r-- | llvm/lib/Transforms/InstCombine/InstCombineCasts.cpp | 36 | ||||
| -rw-r--r-- | llvm/test/Transforms/InstCombine/bswap.ll | 2 |
2 files changed, 2 insertions, 36 deletions
diff --git a/llvm/lib/Transforms/InstCombine/InstCombineCasts.cpp b/llvm/lib/Transforms/InstCombine/InstCombineCasts.cpp index 4d44cc97704..cea510967fe 100644 --- a/llvm/lib/Transforms/InstCombine/InstCombineCasts.cpp +++ b/llvm/lib/Transforms/InstCombine/InstCombineCasts.cpp @@ -628,7 +628,6 @@ Instruction *InstCombiner::commonIntCastTransforms(CastInst &CI) { return 0; } - Instruction *InstCombiner::visitTrunc(TruncInst &CI) { if (Instruction *Result = commonIntCastTransforms(CI)) return Result; @@ -646,41 +645,6 @@ Instruction *InstCombiner::visitTrunc(TruncInst &CI) { return new ICmpInst(ICmpInst::ICMP_NE, Src, Zero); } - // Optimize trunc(lshr(x, c)) to pull the shift through the truncate. - ConstantInt *ShAmtV = 0; - Value *ShiftOp = 0; - if (Src->hasOneUse() && - match(Src, m_LShr(m_Value(ShiftOp), m_ConstantInt(ShAmtV)))) { - uint32_t ShAmt = ShAmtV->getLimitedValue(SrcBitWidth); - - // Get a mask for the bits shifting in. - APInt Mask(APInt::getLowBitsSet(SrcBitWidth, ShAmt).shl(DestBitWidth)); - if (MaskedValueIsZero(ShiftOp, Mask)) { - if (ShAmt >= DestBitWidth) // All zeros. - return ReplaceInstUsesWith(CI, Constant::getNullValue(DestTy)); - - // Okay, we can shrink this. Truncate the input, then return a new - // shift. - Value *V1 = Builder->CreateTrunc(ShiftOp, DestTy, ShiftOp->getName()); - Value *V2 = ConstantExpr::getTrunc(ShAmtV, DestTy); - return BinaryOperator::CreateLShr(V1, V2); - } - } - - // Transform trunc(shl(X, C)) -> shl(trunc(X), C) - if (Src->hasOneUse() && - match(Src, m_Shl(m_Value(ShiftOp), m_ConstantInt(ShAmtV)))) { - uint32_t ShAmt = ShAmtV->getLimitedValue(SrcBitWidth); - if (ShAmt >= DestBitWidth) // All zeros. - return ReplaceInstUsesWith(CI, Constant::getNullValue(DestTy)); - - // Okay, we can shrink this. Truncate the input, then return a new - // shift. - Value *V1 = Builder->CreateTrunc(ShiftOp, DestTy, ShiftOp->getName()); - Value *V2 = ConstantExpr::getTrunc(ShAmtV, DestTy); - return BinaryOperator::CreateShl(V1, V2); - } - return 0; } diff --git a/llvm/test/Transforms/InstCombine/bswap.ll b/llvm/test/Transforms/InstCombine/bswap.ll index c5aa8bede17..168b3e83330 100644 --- a/llvm/test/Transforms/InstCombine/bswap.ll +++ b/llvm/test/Transforms/InstCombine/bswap.ll @@ -1,3 +1,5 @@ +target datalayout = "e-p:32:32:32-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:32:64-f32:32:32-f64:32:64-v64:64:64-v128:128:128-a0:0:64-f80:128:128-n8:16:32" + ; RUN: opt < %s -instcombine -S | \ ; RUN: grep {call.*llvm.bswap} | count 6 |
