[llvm] r323562 - [Hexagon] Make sure that offset on globals matches alignment requirements
Krzysztof Parzyszek via llvm-commits
llvm-commits at lists.llvm.org
Fri Jan 26 13:20:04 PST 2018
Author: kparzysz
Date: Fri Jan 26 13:20:04 2018
New Revision: 323562
URL: http://llvm.org/viewvc/llvm-project?rev=323562&view=rev
Log:
[Hexagon] Make sure that offset on globals matches alignment requirements
A correctly aligned address may happen to be separated into a variable
part and a constant part, where the constant part does not match the
alignment needed in a load/store that uses this address. Such a constant
cannot be used as an immediate offset in an indexed instruction.
When lowering a global address, make sure that if there is an offset
folded into the global, the offset is valid for all uses in load/store
instructions.
Added:
llvm/trunk/test/CodeGen/Hexagon/isel-global-offset-alignment.ll
Modified:
llvm/trunk/lib/Target/Hexagon/HexagonISelLowering.cpp
Modified: llvm/trunk/lib/Target/Hexagon/HexagonISelLowering.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/Hexagon/HexagonISelLowering.cpp?rev=323562&r1=323561&r2=323562&view=diff
==============================================================================
--- llvm/trunk/lib/Target/Hexagon/HexagonISelLowering.cpp (original)
+++ llvm/trunk/lib/Target/Hexagon/HexagonISelLowering.cpp Fri Jan 26 13:20:04 2018
@@ -1472,32 +1472,58 @@ HexagonTargetLowering::LowerGLOBALADDRES
SDLoc dl(Op);
auto *GAN = cast<GlobalAddressSDNode>(Op);
auto PtrVT = getPointerTy(DAG.getDataLayout());
- auto *GV = GAN->getGlobal();
- int64_t Offset = GAN->getOffset();
+ const GlobalValue *GV = GAN->getGlobal();
+ int32_t Offset = GAN->getOffset();
+ int32_t Addend = 0;
+
+ unsigned GlobAlign = GV->getAlignment();
+ if (GlobAlign != 0 && Offset % GlobAlign != 0) {
+ unsigned MinAlign = GlobAlign;
+ for (SDNode *U : GAN->uses()) {
+ if (auto *M = dyn_cast<MemSDNode>(U))
+ MinAlign = std::min(MinAlign, M->getAlignment());
+ }
+ assert(isPowerOf2_32(MinAlign));
+ if (Offset % MinAlign != 0) {
+ Addend = Offset & (MinAlign-1); // Always non-negative.
+ Offset -= Addend;
+ }
+ }
auto &HLOF = *HTM.getObjFileLowering();
Reloc::Model RM = HTM.getRelocationModel();
+ SDValue Res;
if (RM == Reloc::Static) {
SDValue GA = DAG.getTargetGlobalAddress(GV, dl, PtrVT, Offset);
const GlobalObject *GO = GV->getBaseObject();
if (GO && HLOF.isGlobalInSmallSection(GO, HTM))
- return DAG.getNode(HexagonISD::CONST32_GP, dl, PtrVT, GA);
- return DAG.getNode(HexagonISD::CONST32, dl, PtrVT, GA);
+ Res = DAG.getNode(HexagonISD::CONST32_GP, dl, PtrVT, GA);
+ else
+ Res = DAG.getNode(HexagonISD::CONST32, dl, PtrVT, GA);
+ } else {
+ bool UsePCRel = HTM.shouldAssumeDSOLocal(*GV->getParent(), GV);
+ if (UsePCRel) {
+ SDValue GA = DAG.getTargetGlobalAddress(GV, dl, PtrVT, Offset,
+ HexagonII::MO_PCREL);
+ Res = DAG.getNode(HexagonISD::AT_PCREL, dl, PtrVT, GA);
+ } else {
+ // Use GOT index.
+ SDValue GOT = DAG.getGLOBAL_OFFSET_TABLE(PtrVT);
+ SDValue GA = DAG.getTargetGlobalAddress(GV, dl, PtrVT, 0,
+ HexagonII::MO_GOT);
+ SDValue Off = DAG.getConstant(Offset, dl, MVT::i32);
+ Res = DAG.getNode(HexagonISD::AT_GOT, dl, PtrVT, GOT, GA, Off);
+ }
}
- bool UsePCRel = getTargetMachine().shouldAssumeDSOLocal(*GV->getParent(), GV);
- if (UsePCRel) {
- SDValue GA = DAG.getTargetGlobalAddress(GV, dl, PtrVT, Offset,
- HexagonII::MO_PCREL);
- return DAG.getNode(HexagonISD::AT_PCREL, dl, PtrVT, GA);
+ assert(Res.getNode() != nullptr);
+ if (Addend != 0) {
+ SDValue A = DAG.getConstant(Addend, dl, MVT::i32);
+ Res = DAG.getNode(ISD::ADD, dl, MVT::i32, Res, A);
}
- // Use GOT index.
- SDValue GOT = DAG.getGLOBAL_OFFSET_TABLE(PtrVT);
- SDValue GA = DAG.getTargetGlobalAddress(GV, dl, PtrVT, 0, HexagonII::MO_GOT);
- SDValue Off = DAG.getConstant(Offset, dl, MVT::i32);
- return DAG.getNode(HexagonISD::AT_GOT, dl, PtrVT, GOT, GA, Off);
+ return Res;
}
// Specifies that for loads and stores VT can be promoted to PromotedLdStVT.
Added: llvm/trunk/test/CodeGen/Hexagon/isel-global-offset-alignment.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/Hexagon/isel-global-offset-alignment.ll?rev=323562&view=auto
==============================================================================
--- llvm/trunk/test/CodeGen/Hexagon/isel-global-offset-alignment.ll (added)
+++ llvm/trunk/test/CodeGen/Hexagon/isel-global-offset-alignment.ll Fri Jan 26 13:20:04 2018
@@ -0,0 +1,32 @@
+; RUN: llc -march=hexagon < %s | FileCheck %s
+
+; This testcase checks that a valid offset is folded into a global address
+; when it's used in a load or a store instruction. The store in this code
+; is not really properly aligned (bugpoint output from a legal code), but
+; what's important is that the offset on the store instructions is a multiple
+; of the access size. In this case the actual address is @array+30, but that
+; value is not a multiple of 8, so it cannot appear as an immediate in memd.
+; Aside from the fact that @array+30 is not a valid address for memd, make
+; sure that in a memd instruction the offset field is a multiple of 8.
+
+; CHECK: r[[BASE:[0-9]+]] = #6
+; CHECK-DAG: memd(r[[BASE]]+##array+24)
+; CHECK-DAG: memd(r[[BASE]]+##array+32)
+
+
+target datalayout = "e-m:e-p:32:32:32-a:0-n16:32-i64:64:64-i32:32:32-i16:16:16-i1:8:8-f32:32:32-f64:64:64-v32:32:32-v64:64:64-v512:512:512-v1024:1024:1024-v2048:2048:2048"
+target triple = "hexagon"
+
+ at array = external global [1000000 x i16], align 8
+
+define void @fred() #0 {
+b0:
+ %v1 = add nsw i32 0, -1
+ %v2 = getelementptr inbounds [1000000 x i16], [1000000 x i16]* @array, i32 0, i32 %v1
+ %v3 = getelementptr i16, i16* %v2, i32 16
+ %v4 = bitcast i16* %v3 to <8 x i16>*
+ store <8 x i16> zeroinitializer, <8 x i16>* %v4, align 8
+ ret void
+}
+
+attributes #0 = { norecurse nounwind }
More information about the llvm-commits
mailing list