[llvm] r306615 - [InstCombine] Retain TBAA when narrowing memory accesses
Keno Fischer via llvm-commits
llvm-commits at lists.llvm.org
Wed Jun 28 16:36:41 PDT 2017
Author: kfischer
Date: Wed Jun 28 16:36:40 2017
New Revision: 306615
URL: http://llvm.org/viewvc/llvm-project?rev=306615&view=rev
Log:
[InstCombine] Retain TBAA when narrowing memory accesses
Summary:
As discussed on the mailing list it is legal to propagate TBAA to loads/stores
from/to smaller regions of a larger load tagged with TBAA. Do so for
(load->extractvalue)=>(gep->load) and similar foldings.
Reviewed By: sanjoy
Differential Revision: https://reviews.llvm.org/D31954
Added:
llvm/trunk/test/Transforms/InstCombine/extractinsert-tbaa.ll
Modified:
llvm/trunk/lib/Transforms/InstCombine/InstCombineLoadStoreAlloca.cpp
llvm/trunk/lib/Transforms/InstCombine/InstructionCombining.cpp
Modified: llvm/trunk/lib/Transforms/InstCombine/InstCombineLoadStoreAlloca.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/InstCombine/InstCombineLoadStoreAlloca.cpp?rev=306615&r1=306614&r2=306615&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/InstCombine/InstCombineLoadStoreAlloca.cpp (original)
+++ llvm/trunk/lib/Transforms/InstCombine/InstCombineLoadStoreAlloca.cpp Wed Jun 28 16:36:40 2017
@@ -661,6 +661,9 @@ static Instruction *unpackLoadToAggregat
if (NumElements == 1) {
LoadInst *NewLoad = combineLoadToNewType(IC, LI, ST->getTypeAtIndex(0U),
".unpack");
+ AAMDNodes AAMD;
+ LI.getAAMetadata(AAMD);
+ NewLoad->setAAMetadata(AAMD);
return IC.replaceInstUsesWith(LI, IC.Builder->CreateInsertValue(
UndefValue::get(T), NewLoad, 0, Name));
}
@@ -690,6 +693,10 @@ static Instruction *unpackLoadToAggregat
Name + ".elt");
auto EltAlign = MinAlign(Align, SL->getElementOffset(i));
auto *L = IC.Builder->CreateAlignedLoad(Ptr, EltAlign, Name + ".unpack");
+ // Propagate AA metadata. It'll still be valid on the narrowed load.
+ AAMDNodes AAMD;
+ LI.getAAMetadata(AAMD);
+ L->setAAMetadata(AAMD);
V = IC.Builder->CreateInsertValue(V, L, i);
}
@@ -702,6 +709,9 @@ static Instruction *unpackLoadToAggregat
auto NumElements = AT->getNumElements();
if (NumElements == 1) {
LoadInst *NewLoad = combineLoadToNewType(IC, LI, ET, ".unpack");
+ AAMDNodes AAMD;
+ LI.getAAMetadata(AAMD);
+ NewLoad->setAAMetadata(AAMD);
return IC.replaceInstUsesWith(LI, IC.Builder->CreateInsertValue(
UndefValue::get(T), NewLoad, 0, Name));
}
@@ -734,6 +744,9 @@ static Instruction *unpackLoadToAggregat
Name + ".elt");
auto *L = IC.Builder->CreateAlignedLoad(Ptr, MinAlign(Align, Offset),
Name + ".unpack");
+ AAMDNodes AAMD;
+ LI.getAAMetadata(AAMD);
+ L->setAAMetadata(AAMD);
V = IC.Builder->CreateInsertValue(V, L, i);
Offset += EltSize;
}
@@ -1192,7 +1205,11 @@ static bool unpackStoreToAggregate(InstC
AddrName);
auto *Val = IC.Builder->CreateExtractValue(V, i, EltName);
auto EltAlign = MinAlign(Align, SL->getElementOffset(i));
- IC.Builder->CreateAlignedStore(Val, Ptr, EltAlign);
+ llvm::Instruction *NS =
+ IC.Builder->CreateAlignedStore(Val, Ptr, EltAlign);
+ AAMDNodes AAMD;
+ SI.getAAMetadata(AAMD);
+ NS->setAAMetadata(AAMD);
}
return true;
@@ -1239,7 +1256,10 @@ static bool unpackStoreToAggregate(InstC
AddrName);
auto *Val = IC.Builder->CreateExtractValue(V, i, EltName);
auto EltAlign = MinAlign(Align, Offset);
- IC.Builder->CreateAlignedStore(Val, Ptr, EltAlign);
+ Instruction *NS = IC.Builder->CreateAlignedStore(Val, Ptr, EltAlign);
+ AAMDNodes AAMD;
+ SI.getAAMetadata(AAMD);
+ NS->setAAMetadata(AAMD);
Offset += EltSize;
}
Modified: llvm/trunk/lib/Transforms/InstCombine/InstructionCombining.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/InstCombine/InstructionCombining.cpp?rev=306615&r1=306614&r2=306615&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/InstCombine/InstructionCombining.cpp (original)
+++ llvm/trunk/lib/Transforms/InstCombine/InstructionCombining.cpp Wed Jun 28 16:36:40 2017
@@ -2425,9 +2425,15 @@ Instruction *InstCombiner::visitExtractV
Builder->SetInsertPoint(L);
Value *GEP = Builder->CreateInBoundsGEP(L->getType(),
L->getPointerOperand(), Indices);
+ Instruction *NL = Builder->CreateLoad(GEP);
+ // Whatever aliasing information we had for the orignal load must also
+ // hold for the smaller load, so propagate the annotations.
+ AAMDNodes Nodes;
+ L->getAAMetadata(Nodes);
+ NL->setAAMetadata(Nodes);
// Returning the load directly will cause the main loop to insert it in
// the wrong spot, so use replaceInstUsesWith().
- return replaceInstUsesWith(EV, Builder->CreateLoad(GEP));
+ return replaceInstUsesWith(EV, NL);
}
// We could simplify extracts from other values. Note that nested extracts may
// already be simplified implicitly by the above: extract (extract (insert) )
Added: llvm/trunk/test/Transforms/InstCombine/extractinsert-tbaa.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/InstCombine/extractinsert-tbaa.ll?rev=306615&view=auto
==============================================================================
--- llvm/trunk/test/Transforms/InstCombine/extractinsert-tbaa.ll (added)
+++ llvm/trunk/test/Transforms/InstCombine/extractinsert-tbaa.ll Wed Jun 28 16:36:40 2017
@@ -0,0 +1,45 @@
+; RUN: opt -S -instcombine %s -o - | FileCheck %s
+
+%Complex = type { double, double }
+
+; Check that instcombine preserves TBAA when narrowing loads
+define double @teststructextract(%Complex *%val) {
+; CHECK: load double, {{.*}}, !tbaa
+; CHECK-NOT: load %Complex
+ %loaded = load %Complex, %Complex *%val, !tbaa !1
+ %real = extractvalue %Complex %loaded, 0
+ ret double %real
+}
+
+define double @testarrayextract([2 x double] *%val) {
+; CHECK: load double, {{.*}}, !tbaa
+; CHECK-NOT: load [2 x double]
+ %loaded = load [2 x double], [2 x double] *%val, !tbaa !1
+ %real = extractvalue [2 x double] %loaded, 0
+ ret double %real
+}
+
+; Check that inscombine preserves TBAA when breaking up stores
+define void @teststructinsert(%Complex *%loc, double %a, double %b) {
+; CHECK: store double %a, {{.*}}, !tbaa
+; CHECK: store double %b, {{.*}}, !tbaa
+; CHECK-NOT: store %Complex
+ %inserted = insertvalue %Complex undef, double %a, 0
+ %inserted2 = insertvalue %Complex %inserted, double %b, 1
+ store %Complex %inserted2, %Complex *%loc, !tbaa !1
+ ret void
+}
+
+define void @testarrayinsert([2 x double] *%loc, double %a, double %b) {
+; CHECK: store double %a, {{.*}}, !tbaa
+; CHECK: store double %b, {{.*}}, !tbaa
+; CHECK-NOT: store [2 x double]
+ %inserted = insertvalue [2 x double] undef, double %a, 0
+ %inserted2 = insertvalue [2 x double] %inserted, double %b, 1
+ store [2 x double] %inserted2, [2 x double] *%loc, !tbaa !1
+ ret void
+}
+
+!0 = !{!"tbaa_root"}
+!1 = !{!2, !2, i64 0}
+!2 = !{!"Complex", !0, i64 0}
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