diff --git a/llvm/lib/Transforms/Scalar/LoopUnrollPass.cpp b/llvm/lib/Transforms/Scalar/LoopUnrollPass.cpp index 03e1f4cbf60a..9f142a6b357e 100644 --- a/llvm/lib/Transforms/Scalar/LoopUnrollPass.cpp +++ b/llvm/lib/Transforms/Scalar/LoopUnrollPass.cpp @@ -402,14 +402,10 @@ class UnrollAnalyzer : public InstVisitor<UnrollAnalyzer, bool> { else SimpleV = SimplifyBinOp(I.getOpcode(), LHS, RHS, DL); - if (SimpleV) - NumberOfOptimizedInstructions += TTI.getUserCost(&I); - - if (Constant *C = dyn_cast_or_null<Constant>(SimpleV)) { + if (Constant *C = dyn_cast_or_null<Constant>(SimpleV)) SimplifiedValues[&I] = C; - return true; - } - return false; + + return SimpleV; } /// Try to fold load I. @@ -452,7 +448,6 @@ class UnrollAnalyzer : public InstVisitor<UnrollAnalyzer, bool> { assert(CV && "Constant expected."); SimplifiedValues[&I] = CV; - NumberOfOptimizedInstructions += TTI.getUserCost(&I); return true; } @@ -571,7 +566,13 @@ public: // opportunities. for (Instruction &I : *BB) { UnrolledLoopSize += TTI.getUserCost(&I); - Base::visit(I); + + // Visit the instruction to analyze its loop cost after unrolling, + // and if the visitor returns true, then we can optimize this + // instruction away. + if (Base::visit(I)) + NumberOfOptimizedInstructions += TTI.getUserCost(&I); + // If unrolled body turns out to be too big, bail out. if (UnrolledLoopSize - NumberOfOptimizedInstructions > MaxUnrolledLoopSize)