Hello,
Attached patch fixes a severe regression caused by LoopVectorizer when
vectorizing loops with memory accesses to non-zero address spaces. It
simply drops the AS info. It's a rather nasty problem as there is no
way (at least known to me) to disable the loop vectorizer *only* from
clang/opt command line.
Seems like an obvious fix.
http://llvm.org/bugs/show_bug.cgi?id=16306
The patch applies to trunk and 3.3 branches. Tom, could you apply
this to the (upcoming?) 3.3 maintenance branch as well?
Thanks,
--
--Pekka
Index: test/Transforms/LoopVectorize/multiple-address-spaces.ll
===================================================================
--- test/Transforms/LoopVectorize/multiple-address-spaces.ll (revision 0)
+++ test/Transforms/LoopVectorize/multiple-address-spaces.ll (revision 0)
@@ -0,0 +1,47 @@
+; RUN: opt < %s -loop-vectorize -force-vector-unroll=1 -force-vector-width=4 -dce -instcombine -S | FileCheck %s
+
+; From a simple program with two address spaces:
+; char Y[4*10000] __attribute__((address_space(1)));
+; char X[4*10000];
+; int main() {
+; for (int i = 0; i < 4*10000; ++i)
+; X[i] = Y[i] + 1;
+; return 0;
+;}
+
+
+target datalayout = "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-s0:64:64-f80:128:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+@Y = common addrspace(1) global [40000 x i8] zeroinitializer, align 16
+@X = common global [40000 x i8] zeroinitializer, align 16
+
+;CHECK: @main
+;CHECK: bitcast i8 addrspace(1)* %{{.*}} to <4 x i8> addrspace(1)*
+;CHECK: bitcast i8* %{{.*}} to <4 x i8>*
+
+; Function Attrs: nounwind uwtable
+define i32 @main() #0 {
+entry:
+ br label %for.body
+
+for.body: ; preds = %for.body, %entry
+ %indvars.iv = phi i64 [ 0, %entry ], [ %indvars.iv.next, %for.body ]
+ %arrayidx = getelementptr inbounds [40000 x i8] addrspace(1)* @Y, i64 0, i64 %indvars.iv
+ %0 = load i8 addrspace(1)* %arrayidx, align 1, !tbaa !0
+ %add = add i8 %0, 1
+ %arrayidx3 = getelementptr inbounds [40000 x i8]* @X, i64 0, i64 %indvars.iv
+ store i8 %add, i8* %arrayidx3, align 1, !tbaa !0
+ %indvars.iv.next = add i64 %indvars.iv, 1
+ %lftr.wideiv = trunc i64 %indvars.iv.next to i32
+ %exitcond = icmp eq i32 %lftr.wideiv, 40000
+ br i1 %exitcond, label %for.end, label %for.body
+
+for.end: ; preds = %for.body
+ ret i32 0
+}
+
+attributes #0 = { nounwind uwtable "less-precise-fpmad"="false" "no-frame-pointer-elim"="false" "no-frame-pointer-elim-non-leaf"="false" "no-infs-fp-math"="false" "no-nans-fp-math"="false" "unsafe-fp-math"="false" "use-soft-float"="false" }
+
+!0 = metadata !{metadata !"omnipotent char", metadata !1}
+!1 = metadata !{metadata !"Simple C/C++ TBAA"}
Index: lib/Transforms/Vectorize/LoopVectorize.cpp
===================================================================
--- lib/Transforms/Vectorize/LoopVectorize.cpp (revision 183898)
+++ lib/Transforms/Vectorize/LoopVectorize.cpp (working copy)
@@ -964,7 +964,7 @@
Type *DataTy = VectorType::get(ScalarDataTy, VF);
Value *Ptr = LI ? LI->getPointerOperand() : SI->getPointerOperand();
unsigned Alignment = LI ? LI->getAlignment() : SI->getAlignment();
-
+ unsigned AddressSpace = Ptr->getType()->getPointerAddressSpace();
unsigned ScalarAllocatedSize = DL->getTypeAllocSize(ScalarDataTy);
unsigned VectorElementSize = DL->getTypeStoreSize(DataTy)/VF;
@@ -1039,7 +1039,7 @@
PartPtr = Builder.CreateGEP(PartPtr, Builder.getInt32(1 - VF));
}
- Value *VecPtr = Builder.CreateBitCast(PartPtr, DataTy->getPointerTo());
+ Value *VecPtr = Builder.CreateBitCast(PartPtr, DataTy->getPointerTo(AddressSpace));
Builder.CreateStore(StoredVal[Part], VecPtr)->setAlignment(Alignment);
}
}
@@ -1055,7 +1055,7 @@
PartPtr = Builder.CreateGEP(PartPtr, Builder.getInt32(1 - VF));
}
- Value *VecPtr = Builder.CreateBitCast(PartPtr, DataTy->getPointerTo());
+ Value *VecPtr = Builder.CreateBitCast(PartPtr, DataTy->getPointerTo(AddressSpace));
Value *LI = Builder.CreateLoad(VecPtr, "wide.load");
cast<LoadInst>(LI)->setAlignment(Alignment);
Entry[Part] = Reverse ? reverseVector(LI) : LI;
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