diff options
-rw-r--r-- | lib/Transforms/Scalar/IndVarSimplify.cpp | 34 | ||||
-rw-r--r-- | test/Transforms/IndVarSimplify/no-iv-rewrite.ll | 33 |
2 files changed, 52 insertions, 15 deletions
diff --git a/lib/Transforms/Scalar/IndVarSimplify.cpp b/lib/Transforms/Scalar/IndVarSimplify.cpp index 919da35..2a3e472 100644 --- a/lib/Transforms/Scalar/IndVarSimplify.cpp +++ b/lib/Transforms/Scalar/IndVarSimplify.cpp @@ -609,8 +609,7 @@ protected: const SCEVAddRecExpr *GetWideRecurrence(Instruction *NarrowUse); - Instruction *WidenIVUse(Instruction *NarrowUse, - Instruction *NarrowDef, + Instruction *WidenIVUse(Use &NarrowDefUse, Instruction *NarrowDef, Instruction *WideDef); }; } // anonymous namespace @@ -724,9 +723,10 @@ static bool HoistStep(Instruction *IncV, Instruction *InsertPos, /// WidenIVUse - Determine whether an individual user of the narrow IV can be /// widened. If so, return the wide clone of the user. -Instruction *WidenIV::WidenIVUse(Instruction *NarrowUse, - Instruction *NarrowDef, +Instruction *WidenIV::WidenIVUse(Use &NarrowDefUse, Instruction *NarrowDef, Instruction *WideDef) { + Instruction *NarrowUse = cast<Instruction>(NarrowDefUse.getUser()); + // To be consistent with IVUsers, stop traversing the def-use chain at // inner-loop phis or post-loop phis. if (isa<PHINode>(NarrowUse) && LI->getLoopFor(NarrowUse->getParent()) != L) @@ -744,7 +744,7 @@ Instruction *WidenIV::WidenIVUse(Instruction *NarrowUse, unsigned IVWidth = SE->getTypeSizeInBits(WideType); if (CastWidth < IVWidth) { // The cast isn't as wide as the IV, so insert a Trunc. - IRBuilder<> Builder(NarrowUse); + IRBuilder<> Builder(NarrowDefUse); NewDef = Builder.CreateTrunc(WideDef, NarrowUse->getType()); } else { @@ -778,11 +778,15 @@ Instruction *WidenIV::WidenIVUse(Instruction *NarrowUse, // This user does not evaluate to a recurence after widening, so don't // follow it. Instead insert a Trunc to kill off the original use, // eventually isolating the original narrow IV so it can be removed. - IRBuilder<> Builder(NarrowUse); + IRBuilder<> Builder(NarrowDefUse); Value *Trunc = Builder.CreateTrunc(WideDef, NarrowDef->getType()); NarrowUse->replaceUsesOfWith(NarrowDef, Trunc); return 0; } + // We assume that block terminators are not SCEVable. + assert(NarrowUse != NarrowUse->getParent()->getTerminator() && + "can't split terminators"); + // Reuse the IV increment that SCEVExpander created as long as it dominates // NarrowUse. Instruction *WideUse = 0; @@ -876,20 +880,20 @@ PHINode *WidenIV::CreateWideIV(SCEVExpander &Rewriter) { NarrowIVUsers.push_back(std::make_pair(&UI.getUse(), WidePhi)); } while (!NarrowIVUsers.empty()) { - Use *NarrowDefUse; + Use *UsePtr; Instruction *WideDef; - tie(NarrowDefUse, WideDef) = NarrowIVUsers.pop_back_val(); + tie(UsePtr, WideDef) = NarrowIVUsers.pop_back_val(); + Use &NarrowDefUse = *UsePtr; // Process a def-use edge. This may replace the use, so don't hold a // use_iterator across it. - Instruction *NarrowDef = cast<Instruction>(NarrowDefUse->get()); - Instruction *NarrowUse = cast<Instruction>(NarrowDefUse->getUser()); - Instruction *WideUse = WidenIVUse(NarrowUse, NarrowDef, WideDef); + Instruction *NarrowDef = cast<Instruction>(NarrowDefUse.get()); + Instruction *WideUse = WidenIVUse(NarrowDefUse, NarrowDef, WideDef); // Follow all def-use edges from the previous narrow use. if (WideUse) { - for (Value::use_iterator UI = NarrowUse->use_begin(), - UE = NarrowUse->use_end(); UI != UE; ++UI) { + for (Value::use_iterator UI = NarrowDefUse.getUser()->use_begin(), + UE = NarrowDefUse.getUser()->use_end(); UI != UE; ++UI) { NarrowIVUsers.push_back(std::make_pair(&UI.getUse(), WideUse)); } } @@ -1051,6 +1055,10 @@ bool IndVarSimplify::isSimpleIVUser(Instruction *I, const Loop *L) { // Get the symbolic expression for this instruction. const SCEV *S = SE->getSCEV(I); + // We assume that terminators are not SCEVable. + assert((!S || I != I->getParent()->getTerminator()) && + "can't fold terminators"); + // Only consider affine recurrences. const SCEVAddRecExpr *AR = dyn_cast<SCEVAddRecExpr>(S); if (AR && AR->getLoop() == L) diff --git a/test/Transforms/IndVarSimplify/no-iv-rewrite.ll b/test/Transforms/IndVarSimplify/no-iv-rewrite.ll index 462ff58..3395be2 100644 --- a/test/Transforms/IndVarSimplify/no-iv-rewrite.ll +++ b/test/Transforms/IndVarSimplify/no-iv-rewrite.ll @@ -153,8 +153,37 @@ loop: br i1 %cond, label %loop, label %exit exit: - br label %return + ret void +} -return: +define void @maxvisitor(i32 %limit, i32* %base) nounwind { +entry: br label %loop + +; CHECK: loop: +; CHECK: phi i64 +; CHECK: trunc +; CHECK: exit +loop: + %idx = phi i32 [ 0, %entry ], [ %idx.next, %loop.inc ] + %max = phi i32 [ 0, %entry ], [ %max.next, %loop.inc ] + %idxprom = sext i32 %idx to i64 + %adr = getelementptr inbounds i32* %base, i64 %idxprom + %val = load i32* %adr + %cmp19 = icmp sgt i32 %val, %max + br i1 %cmp19, label %if.then, label %if.else + +if.then: + br label %loop.inc + +if.else: + br label %loop.inc + +loop.inc: + %max.next = phi i32 [ %idx, %if.then ], [ %max, %if.else ] + %idx.next = add nsw i32 %idx, 1 + %cmp = icmp slt i32 %idx.next, %limit + br i1 %cmp, label %loop, label %exit + +exit: ret void }
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