[llvm] r323798 - Revert: [Hexagon] Make sure that offset on globals matches alignment requirements

Krzysztof Parzyszek via llvm-commits llvm-commits at lists.llvm.org
Tue Jan 30 10:10:27 PST 2018


Author: kparzysz
Date: Tue Jan 30 10:10:27 2018
New Revision: 323798

URL: http://llvm.org/viewvc/llvm-project?rev=323798&view=rev
Log:
Revert: [Hexagon] Make sure that offset on globals matches alignment requirements

This reverts r323562, since it wasn't actually necessary. Constant-
extended offsets do not need to be aligned, as long as the effective
address is aligned.

Keep the testcase, with a modification which checks that such offsets
are not unnecessarily avoided.

Modified:
    llvm/trunk/lib/Target/Hexagon/HexagonConstExtenders.cpp
    llvm/trunk/lib/Target/Hexagon/HexagonISelLowering.cpp
    llvm/trunk/test/CodeGen/Hexagon/isel-global-offset-alignment.ll

Modified: llvm/trunk/lib/Target/Hexagon/HexagonConstExtenders.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/Hexagon/HexagonConstExtenders.cpp?rev=323798&r1=323797&r2=323798&view=diff
==============================================================================
--- llvm/trunk/lib/Target/Hexagon/HexagonConstExtenders.cpp (original)
+++ llvm/trunk/lib/Target/Hexagon/HexagonConstExtenders.cpp Tue Jan 30 10:10:27 2018
@@ -57,7 +57,6 @@ namespace {
       return *this;
     }
     OffsetRange &shift(int32_t S) {
-      assert(alignTo(std::abs(S), Align) == uint64_t(std::abs(S)));
       Min += S;
       Max += S;
       return *this;

Modified: llvm/trunk/lib/Target/Hexagon/HexagonISelLowering.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/Hexagon/HexagonISelLowering.cpp?rev=323798&r1=323797&r2=323798&view=diff
==============================================================================
--- llvm/trunk/lib/Target/Hexagon/HexagonISelLowering.cpp (original)
+++ llvm/trunk/lib/Target/Hexagon/HexagonISelLowering.cpp Tue Jan 30 10:10:27 2018
@@ -1472,58 +1472,32 @@ HexagonTargetLowering::LowerGLOBALADDRES
   SDLoc dl(Op);
   auto *GAN = cast<GlobalAddressSDNode>(Op);
   auto PtrVT = getPointerTy(DAG.getDataLayout());
-  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 *GV = GAN->getGlobal();
+  int64_t Offset = GAN->getOffset();
 
   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))
-      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);
-    }
+      return DAG.getNode(HexagonISD::CONST32_GP, dl, PtrVT, GA);
+    return DAG.getNode(HexagonISD::CONST32, 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);
+  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);
   }
 
-  return Res;
+  // 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);
 }
 
 // Specifies that for loads and stores VT can be promoted to PromotedLdStVT.

Modified: 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=323798&r1=323797&r2=323798&view=diff
==============================================================================
--- llvm/trunk/test/CodeGen/Hexagon/isel-global-offset-alignment.ll (original)
+++ llvm/trunk/test/CodeGen/Hexagon/isel-global-offset-alignment.ll Tue Jan 30 10:10:27 2018
@@ -1,18 +1,10 @@
 ; 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)
-
+; This should compile without errors, and the offsets with respect to the
+; beginning of the global "array" don't need to be multiples of 8.
+;
+; CHECK-DAG: memd(r0+##array+174)
+; CHECK-DAG: memd(r0+##array+182)
 
 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"
@@ -21,12 +13,21 @@ target triple = "hexagon"
 
 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
+  br i1 undef, label %b3, label %b1
+
+b1:                                               ; preds = %b0
+  %v2 = add i32 0, 512
+  br label %b3
+
+b3:                                               ; preds = %b1, %b0
+  %v4 = phi i32 [ 0, %b0 ], [ %v2, %b1 ]
+  %v5 = or i32 %v4, 1
+  %v6 = add nsw i32 %v5, -1
+  %v7 = getelementptr inbounds [1000000 x i16], [1000000 x i16]* @array, i32 0, i32 %v6
+  %v8 = getelementptr i16, i16* %v7, i32 88
+  %v9 = bitcast i16* %v8 to <8 x i16>*
+  store <8 x i16> zeroinitializer, <8 x i16>* %v9, align 8
+  unreachable
 }
 
 attributes #0 = { norecurse nounwind }




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