[llvm-commits] [llvm] r54821 - in /llvm/trunk: lib/Transforms/Scalar/LoopStrengthReduce.cpp test/Transforms/LoopStrengthReduce/2008-08-14-ShadowIV.ll
Evan Cheng
evan.cheng at apple.com
Sun Aug 17 01:06:30 PDT 2008
Hi Devang,
Looks like this patch is miscompiling some tests. Please look into it.
New Test Failures:
SPEC/CFP2006/447.dealII/447.dealII [LLC compile, LLC-BETA compile, JIT
codegen, , LLC, LLC-BETA]
SPEC/CINT2000/252.eon/252.eon [LLC compile, LLC-BETA compile, JIT
codegen, LLC, LLC-BETA, JIT]
I'll revert it for now.
Evan
On Aug 15, 2008, at 2:21 PM, Devang Patel wrote:
> Author: dpatel
> Date: Fri Aug 15 16:21:34 2008
> New Revision: 54821
>
> URL: http://llvm.org/viewvc/llvm-project?rev=54821&view=rev
> Log:
> Reapply 54786. Add overflow and number of mantissa bits checks.
>
> Modified:
> llvm/trunk/lib/Transforms/Scalar/LoopStrengthReduce.cpp
> llvm/trunk/test/Transforms/LoopStrengthReduce/2008-08-14-
> ShadowIV.ll
>
> Modified: llvm/trunk/lib/Transforms/Scalar/LoopStrengthReduce.cpp
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Scalar/LoopStrengthReduce.cpp?rev=54821&r1=54820&r2=54821&view=diff
>
> =
> =
> =
> =
> =
> =
> =
> =
> ======================================================================
> --- llvm/trunk/lib/Transforms/Scalar/LoopStrengthReduce.cpp (original)
> +++ llvm/trunk/lib/Transforms/Scalar/LoopStrengthReduce.cpp Fri Aug
> 15 16:21:34 2008
> @@ -45,6 +45,7 @@
> STATISTIC(NumInserted, "Number of PHIs inserted");
> STATISTIC(NumVariable, "Number of PHIs with variable strides");
> STATISTIC(NumEliminated , "Number of strides eliminated");
> +STATISTIC(NumShadow , "Number of Shadow IVs optimized");
>
> namespace {
>
> @@ -177,8 +178,13 @@
> IVStrideUse* &CondUse,
> const SCEVHandle* &CondStride);
> void OptimizeIndvars(Loop *L);
> +
> + /// OptimizeShadowIV - If IV is used in a int-to-float cast
> + /// inside the loop then try to eliminate the cast opeation.
> + void OptimizeShadowIV(Loop *L, ICmpInst *Cond,
> + const SCEVHandle *&CondStride);
> bool FindIVUserForCond(ICmpInst *Cond, IVStrideUse *&CondUse,
> - const SCEVHandle *&CondStride);
> + const SCEVHandle *&CondStride);
> bool RequiresTypeConversion(const Type *Ty, const Type *NewTy);
> unsigned CheckForIVReuse(bool, bool, const SCEVHandle&,
> IVExpr&, const Type*,
> @@ -1689,6 +1695,115 @@
> return Cond;
> }
>
> +/// OptimizeShadowIV - If IV is used in a int-to-float cast
> +/// inside the loop then try to eliminate the cast opeation.
> +void LoopStrengthReduce::OptimizeShadowIV(Loop *L, ICmpInst *Cond,
> + const SCEVHandle
> *&CondStride) {
> +
> + const SCEVConstant *SC = dyn_cast<SCEVConstant>(*CondStride);
> + if (!SC) return;
> +
> + SCEVHandle IterationCount = SE->getIterationCount(L);
> + if (isa<SCEVCouldNotCompute>(IterationCount))
> + return;
> +
> + for (unsigned Stride = 0, e = StrideOrder.size(); Stride != e;
> + ++Stride) {
> + std::map<SCEVHandle, IVUsersOfOneStride>::iterator SI =
> + IVUsesByStride.find(StrideOrder[Stride]);
> + assert(SI != IVUsesByStride.end() && "Stride doesn't exist!");
> +
> + for (std::vector<IVStrideUse>::iterator UI = SI-
> >second.Users.begin(),
> + E = SI->second.Users.end(); UI != E; /* empty */) {
> + std::vector<IVStrideUse>::iterator CandidateUI = UI;
> + UI++;
> + Instruction *ShadowUse = CandidateUI->User;
> + const Type *DestTy = NULL;
> +
> + /* If shadow use is a int->float cast then insert a second IV
> + to elminate this cast.
> +
> + for (unsigned i = 0; i < n; ++i)
> + foo((double)i);
> +
> + is trnasformed into
> +
> + double d = 0.0;
> + for (unsigned i = 0; i < n; ++i, ++d)
> + foo(d);
> + */
> + UIToFPInst *UCast = dyn_cast<UIToFPInst>(CandidateUI->User);
> + if (UCast)
> + DestTy = UCast->getDestTy();
> + else {
> + SIToFPInst *SCast = dyn_cast<SIToFPInst>(CandidateUI->User);
> + if (!SCast) continue;
> + DestTy = SCast->getDestTy();
> + }
> +
> + PHINode *PH = dyn_cast<PHINode>(ShadowUse->getOperand(0));
> + if (!PH) continue;
> + if (PH->getNumIncomingValues() != 2) continue;
> +
> + const Type *SrcTy = PH->getType();
> + int Mantissa = DestTy->getFPMantissaWidth();
> + if (Mantissa == -1) continue;
> + if ((int)TD->getTypeSizeInBits(SrcTy) > Mantissa)
> + continue;
> +
> + unsigned Entry, Latch;
> + if (PH->getIncomingBlock(0) == L->getLoopPreheader()) {
> + Entry = 0;
> + Latch = 1;
> + } else {
> + Entry = 1;
> + Latch = 0;
> + }
> +
> + ConstantInt *Init = dyn_cast<ConstantInt>(PH-
> >getIncomingValue(Entry));
> + if (!Init) continue;
> + ConstantFP *NewInit = ConstantFP::get(DestTy, Init-
> >getZExtValue());
> +
> + BinaryOperator *Incr =
> + dyn_cast<BinaryOperator>(PH->getIncomingValue(Latch));
> + if (!Incr) continue;
> + if (Incr->getOpcode() != Instruction::Add
> + && Incr->getOpcode() != Instruction::Sub)
> + continue;
> +
> + /* Initialize new IV, double d = 0.0 in above example. */
> + ConstantInt *C = NULL;
> + if (Incr->getOperand(0) == PH)
> + C = dyn_cast<ConstantInt>(Incr->getOperand(1));
> + else if (Incr->getOperand(1) == PH)
> + C = dyn_cast<ConstantInt>(Incr->getOperand(0));
> + else
> + continue;
> +
> + if (!C) continue;
> +
> + /* Add new PHINode. */
> + PHINode *NewPH = PHINode::Create(DestTy, "IV.S.", PH);
> +
> + /* create new icnrement. '++d' in above example. */
> + ConstantFP *CFP = ConstantFP::get(DestTy, C->getZExtValue());
> + BinaryOperator *NewIncr =
> + BinaryOperator::Create(Incr->getOpcode(),
> + NewPH, CFP, "IV.S.next.", Incr);
> +
> + NewPH->addIncoming(NewInit, PH->getIncomingBlock(Entry));
> + NewPH->addIncoming(NewIncr, PH->getIncomingBlock(Latch));
> +
> + /* Remove cast operation */
> + ShadowUse->replaceAllUsesWith(NewPH);
> + ShadowUse->eraseFromParent();
> + SI->second.Users.erase(CandidateUI);
> + NumShadow++;
> + break;
> + }
> + }
> +}
> +
> // OptimizeIndvars - Now that IVUsesByStride is set up with all of
> the indvar
> // uses in the loop, look to see if we can eliminate some, in favor
> of using
> // common indvars for the different uses.
> @@ -1716,6 +1831,8 @@
> if (!FindIVUserForCond(Cond, CondUse, CondStride))
> return; // setcc doesn't use the IV.
>
> + OptimizeShadowIV(L, Cond, CondStride);
> +
> // If possible, change stride and operands of the compare
> instruction to
> // eliminate one stride.
> Cond = ChangeCompareStride(L, Cond, CondUse, CondStride);
>
> Modified: llvm/trunk/test/Transforms/LoopStrengthReduce/2008-08-14-
> ShadowIV.ll
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/LoopStrengthReduce/2008-08-14-ShadowIV.ll?rev=54821&r1=54820&r2=54821&view=diff
>
> =
> =
> =
> =
> =
> =
> =
> =
> ======================================================================
> --- llvm/trunk/test/Transforms/LoopStrengthReduce/2008-08-14-
> ShadowIV.ll (original)
> +++ llvm/trunk/test/Transforms/LoopStrengthReduce/2008-08-14-
> ShadowIV.ll Fri Aug 15 16:21:34 2008
> @@ -0,0 +1,99 @@
> +; RUN: llvm-as < %s | opt -loop-reduce | llvm-dis | grep "phi
> double" | count 1
> +
> +define void @foobar(i32 %n) nounwind {
> +entry:
> + icmp eq i32 %n, 0 ; <i1>:0 [#uses=2]
> + br i1 %0, label %return, label %bb.nph
> +
> +bb.nph: ; preds = %entry
> + %umax = select i1 %0, i32 1, i32 %n ; <i32> [#uses=1]
> + br label %bb
> +
> +bb: ; preds = %bb, %bb.nph
> + %i.03 = phi i32 [ 0, %bb.nph ], [ %indvar.next, %bb ] ; <i32>
> [#uses=3]
> + tail call void @bar( i32 %i.03 ) nounwind
> + uitofp i32 %i.03 to double ; <double>:1 [#uses=1]
> + tail call void @foo( double %1 ) nounwind
> + %indvar.next = add i32 %i.03, 1 ; <i32> [#uses=2]
> + %exitcond = icmp eq i32 %indvar.next, %umax ; <i1> [#uses=1]
> + br i1 %exitcond, label %return, label %bb
> +
> +return: ; preds = %bb, %entry
> + ret void
> +}
> +
> +; Unable to eliminate cast because the mantissa bits for double are
> not enough
> +; to hold all of i64 IV bits.
> +define void @foobar2(i64 %n) nounwind {
> +entry:
> + icmp eq i64 %n, 0 ; <i1>:0 [#uses=2]
> + br i1 %0, label %return, label %bb.nph
> +
> +bb.nph: ; preds = %entry
> + %umax = select i1 %0, i64 1, i64 %n ; <i64> [#uses=1]
> + br label %bb
> +
> +bb: ; preds = %bb, %bb.nph
> + %i.03 = phi i64 [ 0, %bb.nph ], [ %indvar.next, %bb ] ; <i64>
> [#uses=3]
> + trunc i64 %i.03 to i32 ; <i32>:1 [#uses=1]
> + tail call void @bar( i32 %1 ) nounwind
> + uitofp i64 %i.03 to double ; <double>:2 [#uses=1]
> + tail call void @foo( double %2 ) nounwind
> + %indvar.next = add i64 %i.03, 1 ; <i64> [#uses=2]
> + %exitcond = icmp eq i64 %indvar.next, %umax ; <i1> [#uses=1]
> + br i1 %exitcond, label %return, label %bb
> +
> +return: ; preds = %bb, %entry
> + ret void
> +}
> +
> +; Unable to eliminate cast due to potentional overflow.
> +define void @foobar3() nounwind {
> +entry:
> + tail call i32 (...)* @nn( ) nounwind ; <i32>:0 [#uses=1]
> + icmp eq i32 %0, 0 ; <i1>:1 [#uses=1]
> + br i1 %1, label %return, label %bb
> +
> +bb: ; preds = %bb, %entry
> + %i.03 = phi i32 [ 0, %entry ], [ %3, %bb ] ; <i32> [#uses=3]
> + tail call void @bar( i32 %i.03 ) nounwind
> + uitofp i32 %i.03 to double ; <double>:2 [#uses=1]
> + tail call void @foo( double %2 ) nounwind
> + add i32 %i.03, 1 ; <i32>:3 [#uses=2]
> + tail call i32 (...)* @nn( ) nounwind ; <i32>:4 [#uses=1]
> + icmp ugt i32 %4, %3 ; <i1>:5 [#uses=1]
> + br i1 %5, label %bb, label %return
> +
> +return: ; preds = %bb, %entry
> + ret void
> +}
> +
> +; Unable to eliminate cast due to overflow.
> +define void @foobar4() nounwind {
> +entry:
> + br label %bb.nph
> +
> +bb.nph: ; preds = %entry
> + br label %bb
> +
> +bb: ; preds = %bb, %bb.nph
> + %i.03 = phi i8 [ 0, %bb.nph ], [ %indvar.next, %bb ] ; <i32>
> [#uses=3]
> + %tmp2 = sext i8 %i.03 to i32 ; <i32>:0 [#uses=1]
> + tail call void @bar( i32 %tmp2 ) nounwind
> + %tmp3 = uitofp i8 %i.03 to double ; <double>:1 [#uses=1]
> + tail call void @foo( double %tmp3 ) nounwind
> + %indvar.next = add i8 %i.03, 1 ; <i32> [#uses=2]
> + %tmp = sext i8 %indvar.next to i32
> + %exitcond = icmp eq i32 %tmp, 32767 ; <i1> [#uses=1]
> + br i1 %exitcond, label %return, label %bb
> +
> +return: ; preds = %bb, %entry
> + ret void
> +}
> +
> +declare void @bar(i32)
> +
> +declare void @foo(double)
> +
> +declare i32 @nn(...)
> +
>
>
> _______________________________________________
> llvm-commits mailing list
> llvm-commits at cs.uiuc.edu
> http://lists.cs.uiuc.edu/mailman/listinfo/llvm-commits
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.llvm.org/pipermail/llvm-commits/attachments/20080817/8e65f858/attachment.html>
More information about the llvm-commits
mailing list