From 98c4c5dd78f48542fb0712632fe9f4ebc0ae6da6 Mon Sep 17 00:00:00 2001 From: Adam Nemet Date: Tue, 10 Mar 2015 18:54:23 +0000 Subject: [LAA-memchecks 2/3] Move number of memcheck threshold checking to LV Now the analysis won't "fail" if the memchecks exceed the threshold. It is the transform pass' responsibility to perform the check. This allows the transform pass to further analyze/eliminate the memchecks. E.g. in Loop distribution we only need to check pointers that end up in different partitions. Note that there is a slight change of functionality here. The logic in analyzeLoop is that if dependence checking fails due to non-constant distance between the pointers, another attempt is made to prove safety of the dependences purely using run-time checks. Before this patch we could fail the loop due to exceeding the memcheck threshold after the first step, now we only check the threshold in the client after the full analysis. There is no measurable compile-time effect but I wanted to record this here. llvm-svn: 231817 --- llvm/lib/Transforms/Vectorize/LoopVectorize.cpp | 14 +++++++++++++- 1 file changed, 13 insertions(+), 1 deletion(-) (limited to 'llvm/lib/Transforms/Vectorize/LoopVectorize.cpp') diff --git a/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp b/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp index 18a456f611a..1abefd75c97 100644 --- a/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp +++ b/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp @@ -3874,7 +3874,19 @@ bool LoopVectorizationLegality::canVectorizeMemory() { auto &OptionalReport = LAI->getReport(); if (OptionalReport) emitAnalysis(VectorizationReport(*OptionalReport)); - return LAI->canVectorizeMemory(); + if (!LAI->canVectorizeMemory()) + return false; + + if (LAI->getNumRuntimePointerChecks() > + VectorizerParams::RuntimeMemoryCheckThreshold) { + emitAnalysis(VectorizationReport() + << LAI->getNumRuntimePointerChecks() << " exceeds limit of " + << VectorizerParams::RuntimeMemoryCheckThreshold + << " dependent memory operations checked at runtime"); + DEBUG(dbgs() << "LV: Too many memory checks needed.\n"); + return false; + } + return true; } static bool hasMultipleUsesOf(Instruction *I, -- cgit v1.2.3