diff options
| -rw-r--r-- | llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp | 11 | ||||
| -rw-r--r-- | llvm/test/CodeGen/X86/pr33828.ll | 48 |
2 files changed, 58 insertions, 1 deletions
diff --git a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp index 7e766fb2a74..b733ce76c6a 100644 --- a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp +++ b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp @@ -5279,11 +5279,21 @@ SDValue DAGCombiner::visitRotate(SDNode *N) { SDValue N0 = N->getOperand(0); SDValue N1 = N->getOperand(1); EVT VT = N->getValueType(0); + unsigned Bitsize = VT.getScalarSizeInBits(); // fold (rot x, 0) -> x if (isNullConstantOrNullSplatConstant(N1)) return N0; + // fold (rot x, c) -> (rot x, c % BitSize) + if (ConstantSDNode *Cst = isConstOrConstSplat(N1)) { + if (Cst->getAPIntValue().uge(Bitsize)) { + uint64_t RotAmt = Cst->getAPIntValue().urem(Bitsize); + return DAG.getNode(N->getOpcode(), dl, VT, N0, + DAG.getConstant(RotAmt, dl, N1.getValueType())); + } + } + // fold (rot* x, (trunc (and y, c))) -> (rot* x, (and (trunc y), (trunc c))). if (N1.getOpcode() == ISD::TRUNCATE && N1.getOperand(0).getOpcode() == ISD::AND) { @@ -5302,7 +5312,6 @@ SDValue DAGCombiner::visitRotate(SDNode *N) { unsigned CombineOp = SameSide ? ISD::ADD : ISD::SUB; if (SDValue CombinedShift = DAG.FoldConstantArithmetic(CombineOp, dl, ShiftVT, C1, C2)) { - unsigned Bitsize = VT.getScalarSizeInBits(); SDValue BitsizeC = DAG.getConstant(Bitsize, dl, ShiftVT); SDValue CombinedShiftNorm = DAG.FoldConstantArithmetic( ISD::SREM, dl, ShiftVT, CombinedShift.getNode(), diff --git a/llvm/test/CodeGen/X86/pr33828.ll b/llvm/test/CodeGen/X86/pr33828.ll new file mode 100644 index 00000000000..1b7f44323b6 --- /dev/null +++ b/llvm/test/CodeGen/X86/pr33828.ll @@ -0,0 +1,48 @@ +; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py +; RUN: llc < %s -mtriple=i686-unknown-unknown -mcpu=haswell | FileCheck %s --check-prefix=X86 +; RUN: llc < %s -mtriple=x86_64-unknown-unknown -mcpu=haswell | FileCheck %s --check-prefix=X64 + +@var_580 = external local_unnamed_addr global i8, align 1 + +define void @foo() { +; X86-LABEL: foo: +; X86: # BB#0: # %entry +; X86-NEXT: movsbl var_580, %eax +; X86-NEXT: testl $-536870913, %eax # imm = 0xDFFFFFFF +; X86-NEXT: jne .LBB0_1 +; X86-NEXT: # BB#2: # %if.end13 +; X86-NEXT: retl +; X86-NEXT: .LBB0_1: # %if.then11 +; +; X64-LABEL: foo: +; X64: # BB#0: # %entry +; X64-NEXT: movsbl {{.*}}(%rip), %eax +; X64-NEXT: testl $-536870913, %eax # imm = 0xDFFFFFFF +; X64-NEXT: jne .LBB0_1 +; X64-NEXT: # BB#2: # %if.end13 +; X64-NEXT: retq +; X64-NEXT: .LBB0_1: # %if.then11 +entry: + %tmp = icmp ugt i8 undef, 60 + %phitmp = zext i1 %tmp to i16 + br label %if.end + +if.end: + %tmp1 = load i8, i8* @var_580, align 1 + %conv7 = sext i8 %tmp1 to i32 + %conv8 = zext i16 %phitmp to i32 + %mul = shl nuw nsw i32 %conv8, 1 + %div9 = udiv i32 %mul, 71 + %sub = add nsw i32 %div9, -3 + %shl = shl i32 1, %sub + %neg = xor i32 %shl, -1 + %and = and i32 %neg, %conv7 + %tobool10 = icmp eq i32 %and, 0 + br i1 %tobool10, label %if.end13, label %if.then11 + +if.then11: + unreachable + +if.end13: + ret void +} |
