diff options
| -rw-r--r-- | lib/CodeGen/SelectionDAG/SelectionDAG.cpp | 28 | ||||
| -rw-r--r-- | test/CodeGen/ARM/zextload_demandedbits.ll | 35 |
2 files changed, 51 insertions, 12 deletions
diff --git a/lib/CodeGen/SelectionDAG/SelectionDAG.cpp b/lib/CodeGen/SelectionDAG/SelectionDAG.cpp index 35707e86ce..64244313a3 100644 --- a/lib/CodeGen/SelectionDAG/SelectionDAG.cpp +++ b/lib/CodeGen/SelectionDAG/SelectionDAG.cpp @@ -1917,7 +1917,8 @@ void SelectionDAG::ComputeMaskedBits(SDValue Op, APInt &KnownZero, } case ISD::LOAD: { LoadSDNode *LD = cast<LoadSDNode>(Op); - if (ISD::isZEXTLoad(Op.getNode())) { + // If this is a ZEXTLoad and we are looking at the loaded value. + if (ISD::isZEXTLoad(Op.getNode()) && Op.getResNo() == 0) { EVT VT = LD->getMemoryVT(); unsigned MemBits = VT.getScalarType().getSizeInBits(); KnownZero |= APInt::getHighBitsSet(BitWidth, BitWidth - MemBits); @@ -2287,17 +2288,20 @@ unsigned SelectionDAG::ComputeNumSignBits(SDValue Op, unsigned Depth) const{ break; } - // Handle LOADX separately here. EXTLOAD case will fallthrough. - if (LoadSDNode *LD = dyn_cast<LoadSDNode>(Op)) { - unsigned ExtType = LD->getExtensionType(); - switch (ExtType) { - default: break; - case ISD::SEXTLOAD: // '17' bits known - Tmp = LD->getMemoryVT().getScalarType().getSizeInBits(); - return VTBits-Tmp+1; - case ISD::ZEXTLOAD: // '16' bits known - Tmp = LD->getMemoryVT().getScalarType().getSizeInBits(); - return VTBits-Tmp; + // If we are looking at the loaded value of the SDNode. + if (Op.getResNo() == 0) { + // Handle LOADX separately here. EXTLOAD case will fallthrough. + if (LoadSDNode *LD = dyn_cast<LoadSDNode>(Op)) { + unsigned ExtType = LD->getExtensionType(); + switch (ExtType) { + default: break; + case ISD::SEXTLOAD: // '17' bits known + Tmp = LD->getMemoryVT().getScalarType().getSizeInBits(); + return VTBits-Tmp+1; + case ISD::ZEXTLOAD: // '16' bits known + Tmp = LD->getMemoryVT().getScalarType().getSizeInBits(); + return VTBits-Tmp; + } } } diff --git a/test/CodeGen/ARM/zextload_demandedbits.ll b/test/CodeGen/ARM/zextload_demandedbits.ll new file mode 100644 index 0000000000..3d3269cae2 --- /dev/null +++ b/test/CodeGen/ARM/zextload_demandedbits.ll @@ -0,0 +1,35 @@ +; RUN: llc < %s -march=arm -mtriple="thumbv7-apple-ios3.0.0" | FileCheck %s + +target datalayout = "e-p:32:32:32-i1:8:32-i8:8:32-i16:16:32-i32:32:32-i64:32:64-f32:32:32-f64:32:64-v64:32:64-v128:32:128-a0:0:32-n32-S32" + +%struct.eggs = type { %struct.spam, i16 } +%struct.spam = type { [3 x i32] } +%struct.barney = type { [2 x i32], [2 x i32] } + +; Make sure that the sext op does not get lost due to ComputeMaskedBits. +; CHECK: quux +; CHECK: lsl +; CHECK: asr +; CHECK: bl +; CHECK: pop +define void @quux(%struct.eggs* %arg) { +bb: + %tmp1 = getelementptr inbounds %struct.eggs* %arg, i32 0, i32 1 + %0 = load i16* %tmp1, align 2 + %tobool = icmp eq i16 %0, 0 + br i1 %tobool, label %bb16, label %bb3 + +bb3: ; preds = %bb + %tmp4 = bitcast i16* %tmp1 to i8* + %tmp5 = ptrtoint i16* %tmp1 to i32 + %tmp6 = shl i32 %tmp5, 20 + %tmp7 = ashr exact i32 %tmp6, 20 + %tmp14 = getelementptr inbounds %struct.barney* undef, i32 %tmp7 + %tmp15 = tail call i32 @widget(%struct.barney* %tmp14, i8* %tmp4, i32 %tmp7) + br label %bb16 + +bb16: ; preds = %bb3, %bb + ret void +} + +declare i32 @widget(%struct.barney*, i8*, i32) |