[llvm-commits] [llvm] r151621 - in /llvm/trunk: lib/Transforms/Scalar/DeadStoreElimination.cpp test/Transforms/DeadStoreElimination/OverwriteStoreStart.ll
Pete Cooper
peter_cooper at apple.com
Mon Feb 27 21:06:24 PST 2012
Author: pete
Date: Mon Feb 27 23:06:24 2012
New Revision: 151621
URL: http://llvm.org/viewvc/llvm-project?rev=151621&view=rev
Log:
Reverted r152620 - DSE: Shorten memset when a later store overwrites the start of it. There were all sorts of buildbot issues
Removed:
llvm/trunk/test/Transforms/DeadStoreElimination/OverwriteStoreStart.ll
Modified:
llvm/trunk/lib/Transforms/Scalar/DeadStoreElimination.cpp
Modified: llvm/trunk/lib/Transforms/Scalar/DeadStoreElimination.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Scalar/DeadStoreElimination.cpp?rev=151621&r1=151620&r2=151621&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/Scalar/DeadStoreElimination.cpp (original)
+++ llvm/trunk/lib/Transforms/Scalar/DeadStoreElimination.cpp Mon Feb 27 23:06:24 2012
@@ -259,13 +259,6 @@
}
}
-
-/// isMemset - Returns true if this instruction is an intrinsic memset
-static bool isMemset(Instruction *I) {
- IntrinsicInst *II = dyn_cast<IntrinsicInst>(I);
- return II && II->getIntrinsicID() == Intrinsic::memset;
-}
-
/// getStoredPointerOperand - Return the pointer that is being written to.
static Value *getStoredPointerOperand(Instruction *I) {
if (StoreInst *SI = dyn_cast<StoreInst>(I))
@@ -317,17 +310,14 @@
{
OverwriteComplete,
OverwriteEnd,
- OverwriteStart,
OverwriteUnknown
};
}
/// isOverwrite - Return 'OverwriteComplete' if a store to the 'Later' location
/// completely overwrites a store to the 'Earlier' location.
-/// 'OverwriteEnd' if the end of the 'Earlier' location is completely
-/// overwritten by 'Later', 'OverWriteStart' if the start of 'Earlier'
-/// is completely overwritten by 'Later' or 'OverwriteUnknown' if nothing
-/// can be determined
+/// 'OverwriteEnd' if the end of the 'Earlier' location is completely
+/// overwritten by 'Later', or 'OverwriteUnknown' if nothing can be determined
static OverwriteResult isOverwrite(const AliasAnalysis::Location &Later,
const AliasAnalysis::Location &Earlier,
AliasAnalysis &AA,
@@ -428,21 +418,6 @@
LaterOff < int64_t(EarlierOff + Earlier.Size) &&
int64_t(LaterOff + Later.Size) >= int64_t(EarlierOff + Earlier.Size))
return OverwriteEnd;
-
- // The other interesting case is if the later store overwrites the end of
- // the earlier store
- //
- // |--earlier--|
- // |-- later --|
- //
- // In this case we may want to trim the size of earlier to avoid generating
- // writes to addresses which will definitely be overwritten later
- if (EarlierOff >= LaterOff &&
- EarlierOff < int64_t(LaterOff + Later.Size) &&
- int64_t(EarlierOff + Earlier.Size) >= int64_t(LaterOff + Later.Size)) {
- LaterOff = LaterOff + Later.Size;
- return OverwriteStart;
- }
// Otherwise, they don't completely overlap.
return OverwriteUnknown;
@@ -614,45 +589,6 @@
DepIntrinsic->setLength(TrimmedLength);
MadeChange = true;
}
- } else if (OR == OverwriteStart && isMemset(DepWrite)) {
- // TODO: base this on the target vector size so that if the earlier
- // store was too small to get vector writes anyway then its likely
- // a good idea to shorten it
- // Power of 2 vector writes are probably always a bad idea to optimize
- // as any store/memset/memcpy is likely using vector instructions so
- // shortening it to not vector size is likely to be slower
- // TODO: shorten memcpy and memmove by offsetting the source address.
- MemIntrinsic* DepIntrinsic = cast<MemIntrinsic>(DepWrite);
- unsigned DepWriteAlign = DepIntrinsic->getAlignment();
- if (llvm::isPowerOf2_64(InstWriteOffset) ||
- ((DepWriteAlign != 0) && InstWriteOffset % DepWriteAlign == 0)) {
-
- DEBUG(dbgs() << "DSE: Remove Dead Store:\n OW START: "
- << *DepWrite << "\n KILLER (offset "
- << InstWriteOffset << ", "
- << DepWriteOffset << ", "
- << DepLoc.Size << ")"
- << *Inst << '\n');
-
- Value* DepWriteLength = DepIntrinsic->getLength();
- Value* TrimmedLength = ConstantInt::get(DepWriteLength->getType(),
- DepLoc.Size -
- (InstWriteOffset -
- DepWriteOffset));
- DepIntrinsic->setLength(TrimmedLength);
- const TargetData *TD = AA->getTargetData();
- Type *IntPtrTy = TD->getIntPtrType(BB.getContext());
- Value* Offset = ConstantInt::get(IntPtrTy,
- InstWriteOffset - DepWriteOffset);
- // Offset the start of the memset with a GEP. As the memset type is
- // i8* a GEP will do this without needing to use ptrtoint, etc.
- Value *Dest = GetElementPtrInst::Create(DepIntrinsic->getRawDest(),
- Offset,
- "",
- DepWrite);
- DepIntrinsic->setDest(Dest);
- MadeChange = true;
- }
}
}
Removed: llvm/trunk/test/Transforms/DeadStoreElimination/OverwriteStoreStart.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/DeadStoreElimination/OverwriteStoreStart.ll?rev=151620&view=auto
==============================================================================
--- llvm/trunk/test/Transforms/DeadStoreElimination/OverwriteStoreStart.ll (original)
+++ llvm/trunk/test/Transforms/DeadStoreElimination/OverwriteStoreStart.ll (removed)
@@ -1,71 +0,0 @@
-; RUN: opt < %s -basicaa -dse -S | FileCheck %s
-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"
-
-%struct.vec2 = type { <4 x i32>, <4 x i32> }
-%struct.vec2plusi = type { <4 x i32>, <4 x i32>, i32 }
-
- at glob1 = global %struct.vec2 zeroinitializer, align 16
- at glob2 = global %struct.vec2plusi zeroinitializer, align 16
-
-define void @write4to8(i32* nocapture %p) nounwind uwtable ssp {
-; CHECK: @write4to8
-entry:
- %arrayidx0 = getelementptr inbounds i32* %p, i64 1
- %p3 = bitcast i32* %arrayidx0 to i8*
-; CHECK: call void @llvm.memset.p0i8.i64(i8* %{{[0-9]+}}, i8 0, i64 24, i32 4, i1 false)
- call void @llvm.memset.p0i8.i64(i8* %p3, i8 0, i64 28, i32 4, i1 false)
- %arrayidx1 = getelementptr inbounds i32* %p, i64 1
- store i32 1, i32* %arrayidx1, align 4
- ret void
-}
-
-define void @write4to12(i32* nocapture %p) nounwind uwtable ssp {
-; CHECK: @write4to12
-entry:
-%arrayidx0 = getelementptr inbounds i32* %p, i64 1
-%p3 = bitcast i32* %arrayidx0 to i8*
-; CHECK: call void @llvm.memset.p0i8.i64(i8* %{{[0-9]+}}, i8 0, i64 20, i32 4, i1 false)
-call void @llvm.memset.p0i8.i64(i8* %p3, i8 0, i64 28, i32 4, i1 false)
-%arrayidx1 = bitcast i32* %arrayidx0 to i64*
-store i64 1, i64* %arrayidx1, align 4
-ret void
-}
-
-define void @write4to8_2(i32* nocapture %p) nounwind uwtable ssp {
-; CHECK: @write4to8_2
-entry:
-%arrayidx0 = getelementptr inbounds i32* %p, i64 1
-%p3 = bitcast i32* %arrayidx0 to i8*
-; CHECK: call void @llvm.memset.p0i8.i64(i8* %{{[0-9]+}}, i8 0, i64 24, i32 4, i1 false)
-call void @llvm.memset.p0i8.i64(i8* %p3, i8 0, i64 28, i32 4, i1 false)
-%arrayidx1 = bitcast i32* %p to i64*
-store i64 1, i64* %arrayidx1, align 4
-ret void
-}
-
-define void @dontwrite4to6(i32* nocapture %p) nounwind uwtable ssp {
-; CHECK: @dontwrite4to6
-entry:
-%arrayidx0 = getelementptr inbounds i32* %p, i64 1
-%p3 = bitcast i32* %arrayidx0 to i8*
-; CHECK: call void @llvm.memset.p0i8.i64(i8* %p3, i8 0, i64 28, i32 4, i1 false)
-call void @llvm.memset.p0i8.i64(i8* %p3, i8 0, i64 28, i32 4, i1 false)
-%arrayidx1 = bitcast i32* %arrayidx0 to i16*
-store i16 1, i16* %arrayidx1, align 4
-ret void
-}
-
-define void @write4to8_neg_gep(i32* nocapture %p) nounwind uwtable ssp {
-; CHECK: @write4to8_neg_gep
-entry:
-%arrayidx0 = getelementptr inbounds i32* %p, i64 -1
-%p3 = bitcast i32* %arrayidx0 to i8*
-; CHECK: call void @llvm.memset.p0i8.i64(i8* %{{[0-9]+}}, i8 0, i64 24, i32 4, i1 false)
-call void @llvm.memset.p0i8.i64(i8* %p3, i8 0, i64 28, i32 4, i1 false)
-%neg2 = getelementptr inbounds i32* %p, i64 -2
-%arrayidx1 = bitcast i32* %neg2 to i64*
-store i64 1, i64* %arrayidx1, align 4
-ret void
-}
-
-declare void @llvm.memset.p0i8.i64(i8* nocapture, i8, i64, i32, i1) nounwind
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