From 2da70d1792abf0ad837578991f492a3dd0364118 Mon Sep 17 00:00:00 2001 From: Shuxin Yang Date: Fri, 5 Apr 2013 21:07:08 +0000 Subject: Disable the optimization about promoting vector-element-access with symbolic index. This optimization is unstable at this moment; it 1) block us on a very important application 2) PR15200 3) test6 and test7 in test/Transforms/ScalarRepl/dynamic-vector-gep.ll (the CHECK command compare the output against wrong result) I personally believe this optimization should not have any impact on the autovectorized code, as auto-vectorizer is supposed to put gather/scatter in a "right" way. Although in theory downstream optimizaters might reveal some gather/scatter optimization opportunities, the chance is quite slim. For the hand-crafted vectorizing code, in term of redundancy elimination, load-CSE, copy-propagation and DSE can collectively achieve the same result, but in much simpler way. On the other hand, these optimizers are able to improve the code in a incremental way; in contrast, SROA is sort of all-or-none approach. However, SROA might slighly win in stack size, as it tries to figure out a stretch of memory tightenly cover the area accessed by the dynamic index. rdar://13174884 PR15200 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@178912 91177308-0d34-0410-b5e6-96231b3b80d8 --- lib/Transforms/Scalar/ScalarReplAggregates.cpp | 13 ++----------- 1 file changed, 2 insertions(+), 11 deletions(-) (limited to 'lib') diff --git a/lib/Transforms/Scalar/ScalarReplAggregates.cpp b/lib/Transforms/Scalar/ScalarReplAggregates.cpp index e590a374ea..8a8fbd3c4e 100644 --- a/lib/Transforms/Scalar/ScalarReplAggregates.cpp +++ b/lib/Transforms/Scalar/ScalarReplAggregates.cpp @@ -1724,17 +1724,8 @@ void SROA::isSafeGEP(GetElementPtrInst *GEPI, continue; ConstantInt *IdxVal = dyn_cast(GEPIt.getOperand()); - if (!IdxVal) { - // Non constant GEPs are only a problem on arrays, structs, and pointers - // Vectors can be dynamically indexed. - // FIXME: Add support for dynamic indexing on arrays. This should be - // ok on any subarrays of the alloca array, eg, a[0][i] is ok, but a[i][0] - // isn't. - if (!(*GEPIt)->isVectorTy()) - return MarkUnsafe(Info, GEPI); - NonConstant = true; - NonConstantIdxSize = TD->getTypeAllocSize(*GEPIt); - } + if (!IdxVal) + return MarkUnsafe(Info, GEPI); } // Compute the offset due to this GEP and check if the alloca has a -- cgit v1.2.3