diff options
| -rw-r--r-- | lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp | 9 | ||||
| -rw-r--r-- | test/CodeGen/Generic/2010-11-11-ReturnBigBuffer.ll | 32 |
2 files changed, 6 insertions, 35 deletions
diff --git a/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp b/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp index a471aab..81efc0b 100644 --- a/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp +++ b/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp @@ -76,12 +76,15 @@ LimitFPPrecision("limit-float-precision", // load clustering may not complete in reasonable time. It is difficult to // recognize and avoid this situation within each individual analysis, and // future analyses are likely to have the same behavior. Limiting DAG width is -// the safe approach, and will be especially important with global DAGs. See -// 2010-11-11-ReturnBigBuffer.ll. +// the safe approach, and will be especially important with global DAGs. // // MaxParallelChains default is arbitrarily high to avoid affecting // optimization, but could be lowered to improve compile time. Any ld-ld-st-st -// sequence over this should have been converted to llvm.memcpy by the frontend. +// sequence over this should have been converted to llvm.memcpy by the +// frontend. It easy to induce this behavior with .ll code such as: +// %buffer = alloca [4096 x i8] +// %data = load [4096 x i8]* %argPtr +// store [4096 x i8] %data, [4096 x i8]* %buffer static cl::opt<unsigned> MaxParallelChains("dag-chain-limit", cl::desc("Max parallel isel dag chains"), cl::init(64), cl::Hidden); diff --git a/test/CodeGen/Generic/2010-11-11-ReturnBigBuffer.ll b/test/CodeGen/Generic/2010-11-11-ReturnBigBuffer.ll deleted file mode 100644 index bf5939d..0000000 --- a/test/CodeGen/Generic/2010-11-11-ReturnBigBuffer.ll +++ /dev/null @@ -1,32 +0,0 @@ -; RUN: llc < %s -; PR8287: SelectionDag scheduling time. -; Yes, some front end really produces this code. But that is a -; separate bug. This is more an example than a real test, because I -; don't know how give llvm-lit a timeout. - -define void @foo([4096 x i8]* %arg1, [4096 x i8]* %arg2) { - %buffer = alloca [4096 x i8] - %pbuf = alloca [4096 x i8]* - store [4096 x i8]* %buffer, [4096 x i8]** %pbuf - - %parg1 = alloca [4096 x i8]* - store [4096 x i8]* %arg1, [4096 x i8]** %parg1 - - %parg2 = alloca [4096 x i8]* - store [4096 x i8]* %arg2, [4096 x i8]** %parg2 - - ; The original test case has intermediate blocks. - ; Presumably something fills in "buffer". - - %bufferCopy1 = load [4096 x i8]** %pbuf - %dataCopy1 = load [4096 x i8]* %bufferCopy1 - %arg1Copy = load [4096 x i8]** %parg1 - store [4096 x i8] %dataCopy1, [4096 x i8]* %arg1Copy - - %bufferCopy2 = load [4096 x i8]** %pbuf - %dataCopy2 = load [4096 x i8]* %bufferCopy2 - %arg2Copy = load [4096 x i8]** %parg2 - store [4096 x i8] %dataCopy2, [4096 x i8]* %arg2Copy - - ret void -} |