From 3fa842d791ff114d13159282933c7c15c5579cd7 Mon Sep 17 00:00:00 2001 From: Chandler Carruth Date: Mon, 27 Jan 2014 11:12:14 +0000 Subject: [PATCH] [vectorizer] Fix a trivial oversight where we always requested the number of vector registers rather than toggling between vector and scalar register number based on VF. I don't have a test case as I spotted this by inspection and on X86 it only makes a difference if your target is lacking SSE and thus has *no* vector registers. If someone wants to add a test case for this for ARM or somewhere else where this is more significant, that would be awesome. Also made the variable name a bit more sensible while I'm here. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@200211 91177308-0d34-0410-b5e6-96231b3b80d8 --- lib/Transforms/Vectorize/LoopVectorize.cpp | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/lib/Transforms/Vectorize/LoopVectorize.cpp b/lib/Transforms/Vectorize/LoopVectorize.cpp index 66134bd95d0..f904765f41e 100644 --- a/lib/Transforms/Vectorize/LoopVectorize.cpp +++ b/lib/Transforms/Vectorize/LoopVectorize.cpp @@ -4962,9 +4962,9 @@ LoopVectorizationCostModel::selectUnrollFactor(bool OptForSize, if (TC > 1 && TC < TinyTripCountUnrollThreshold) return 1; - unsigned TargetVectorRegisters = TTI.getNumberOfRegisters(true); - DEBUG(dbgs() << "LV: The target has " << TargetVectorRegisters << - " vector registers\n"); + unsigned TargetNumRegisters = TTI.getNumberOfRegisters(VF > 1); + DEBUG(dbgs() << "LV: The target has " << TargetNumRegisters << + " registers\n"); LoopVectorizationCostModel::RegisterUsage R = calculateRegisterUsage(); // We divide by these constants so assume that we have at least one @@ -4978,7 +4978,7 @@ LoopVectorizationCostModel::selectUnrollFactor(bool OptForSize, // Next, divide the remaining registers by the number of registers that is // required by the loop, in order to estimate how many parallel instances // fit without causing spills. - unsigned UF = (TargetVectorRegisters - R.LoopInvariantRegs) / R.MaxLocalUsers; + unsigned UF = (TargetNumRegisters - R.LoopInvariantRegs) / R.MaxLocalUsers; // Clamp the unroll factor ranges to reasonable factors. unsigned MaxUnrollSize = TTI.getMaximumUnrollFactor();