[llvm-commits] [llvm] r82864 - in /llvm/trunk: lib/Analysis/ScalarEvolutionExpander.cpp test/Transforms/IndVarSimplify/preserve-gep-loop-variant.ll
Dan Gohman
gohman at apple.com
Sat Sep 26 09:11:57 PDT 2009
Author: djg
Date: Sat Sep 26 11:11:57 2009
New Revision: 82864
URL: http://llvm.org/viewvc/llvm-project?rev=82864&view=rev
Log:
Fix a case where ScalarEvolution was expanding pointer arithmetic
to inttoptr/ptrtoint unnecessarily.
Added:
llvm/trunk/test/Transforms/IndVarSimplify/preserve-gep-loop-variant.ll
Modified:
llvm/trunk/lib/Analysis/ScalarEvolutionExpander.cpp
Modified: llvm/trunk/lib/Analysis/ScalarEvolutionExpander.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Analysis/ScalarEvolutionExpander.cpp?rev=82864&r1=82863&r2=82864&view=diff
==============================================================================
--- llvm/trunk/lib/Analysis/ScalarEvolutionExpander.cpp (original)
+++ llvm/trunk/lib/Analysis/ScalarEvolutionExpander.cpp Sat Sep 26 11:11:57 2009
@@ -508,20 +508,37 @@
}
Value *SCEVExpander::visitAddExpr(const SCEVAddExpr *S) {
+ int NumOperands = S->getNumOperands();
const Type *Ty = SE.getEffectiveSCEVType(S->getType());
- Value *V = expand(S->getOperand(S->getNumOperands()-1));
+
+ // Find the index of an operand to start with. Choose the operand with
+ // pointer type, if there is one, or the last operand otherwise.
+ int PIdx = 0;
+ for (; PIdx != NumOperands - 1; ++PIdx)
+ if (isa<PointerType>(S->getOperand(PIdx)->getType())) break;
+
+ // Expand code for the operand that we chose.
+ Value *V = expand(S->getOperand(PIdx));
// Turn things like ptrtoint+arithmetic+inttoptr into GEP. See the
// comments on expandAddToGEP for details.
if (const PointerType *PTy = dyn_cast<PointerType>(V->getType())) {
+ // Take the operand at PIdx out of the list.
const SmallVectorImpl<const SCEV *> &Ops = S->getOperands();
- return expandAddToGEP(&Ops[0], &Ops[Ops.size() - 1], PTy, Ty, V);
+ SmallVector<const SCEV *, 8> NewOps;
+ NewOps.insert(NewOps.end(), Ops.begin(), Ops.begin() + PIdx);
+ NewOps.insert(NewOps.end(), Ops.begin() + PIdx + 1, Ops.end());
+ // Make a GEP.
+ return expandAddToGEP(NewOps.begin(), NewOps.end(), PTy, Ty, V);
}
+ // Otherwise, we'll expand the rest of the SCEVAddExpr as plain integer
+ // arithmetic.
V = InsertNoopCastOfTo(V, Ty);
// Emit a bunch of add instructions
- for (int i = S->getNumOperands()-2; i >= 0; --i) {
+ for (int i = NumOperands-1; i >= 0; --i) {
+ if (i == PIdx) continue;
Value *W = expandCodeFor(S->getOperand(i), Ty);
V = InsertBinop(Instruction::Add, V, W);
}
Added: llvm/trunk/test/Transforms/IndVarSimplify/preserve-gep-loop-variant.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/IndVarSimplify/preserve-gep-loop-variant.ll?rev=82864&view=auto
==============================================================================
--- llvm/trunk/test/Transforms/IndVarSimplify/preserve-gep-loop-variant.ll (added)
+++ llvm/trunk/test/Transforms/IndVarSimplify/preserve-gep-loop-variant.ll Sat Sep 26 11:11:57 2009
@@ -0,0 +1,41 @@
+; RUN: opt < %s -indvars -S > %t
+; RUN: not grep inttoptr %t
+; RUN: not grep ptrtoint %t
+; RUN: grep scevgep %t
+
+; Indvars shouldn't need inttoptr/ptrtoint to expand an address here.
+
+define void @foo(i8* %p) nounwind {
+entry:
+ br i1 true, label %bb.nph, label %for.end
+
+for.cond:
+ %phitmp = icmp slt i64 %inc, 20
+ br i1 %phitmp, label %for.body, label %for.cond.for.end_crit_edge
+
+for.cond.for.end_crit_edge:
+ br label %for.end
+
+bb.nph:
+ br label %for.body
+
+for.body:
+ %storemerge1 = phi i64 [ %inc, %for.cond ], [ 0, %bb.nph ]
+ %call = tail call i64 @bar() nounwind
+ %call2 = tail call i64 @car() nounwind
+ %conv = trunc i64 %call2 to i8
+ %conv3 = sext i8 %conv to i64
+ %add = add nsw i64 %call, %storemerge1
+ %add4 = add nsw i64 %add, %conv3
+ %arrayidx = getelementptr inbounds i8* %p, i64 %add4
+ store i8 0, i8* %arrayidx
+ %inc = add nsw i64 %storemerge1, 1
+ br label %for.cond
+
+for.end:
+ ret void
+}
+
+declare i64 @bar()
+
+declare i64 @car()
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