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| author | Michael J. Spencer <bigcheesegs@gmail.com> | 2017-02-09 21:46:49 +0000 |
|---|---|---|
| committer | Michael J. Spencer <bigcheesegs@gmail.com> | 2017-02-09 21:46:49 +0000 |
| commit | 714d9d22ad7bd19679a042239b9e384d38303610 (patch) | |
| tree | de174277a5036118fbc2fd14edc7d0b8d6676bb4 | |
| parent | 857aba44106ac543cbd8210cff56db46e7287c84 (diff) | |
| download | bcm5719-llvm-714d9d22ad7bd19679a042239b9e384d38303610.tar.gz bcm5719-llvm-714d9d22ad7bd19679a042239b9e384d38303610.zip | |
[LoadCombine] Fix combining of loads which span an aliasing store.
Fixes PR31517
Differential Revision: https://reviews.llvm.org/D28922
llvm-svn: 294632
| -rw-r--r-- | llvm/lib/Transforms/Scalar/LoadCombine.cpp | 6 | ||||
| -rw-r--r-- | llvm/test/Transforms/LoadCombine/load-combine-aa.ll | 21 |
2 files changed, 26 insertions, 1 deletions
diff --git a/llvm/lib/Transforms/Scalar/LoadCombine.cpp b/llvm/lib/Transforms/Scalar/LoadCombine.cpp index 389f1c595aa..61b7804b59b 100644 --- a/llvm/lib/Transforms/Scalar/LoadCombine.cpp +++ b/llvm/lib/Transforms/Scalar/LoadCombine.cpp @@ -245,13 +245,17 @@ bool LoadCombine::runOnBasicBlock(BasicBlock &BB) { bool Combined = false; unsigned Index = 0; for (auto &I : BB) { - if (I.mayThrow() || (I.mayWriteToMemory() && AST.containsUnknown(&I))) { + if (I.mayThrow() || AST.containsUnknown(&I)) { if (combineLoads(LoadMap)) Combined = true; LoadMap.clear(); AST.clear(); continue; } + if (I.mayWriteToMemory()) { + AST.add(&I); + continue; + } LoadInst *LI = dyn_cast<LoadInst>(&I); if (!LI) continue; diff --git a/llvm/test/Transforms/LoadCombine/load-combine-aa.ll b/llvm/test/Transforms/LoadCombine/load-combine-aa.ll index fc639c0bc05..ad66a1a6387 100644 --- a/llvm/test/Transforms/LoadCombine/load-combine-aa.ll +++ b/llvm/test/Transforms/LoadCombine/load-combine-aa.ll @@ -37,3 +37,24 @@ define i64 @test2(i32* nocapture readonly %a, i32* nocapture readonly %b) { ret i64 %add } +%rec11 = type { i16, i16, i16 } +@str = global %rec11 { i16 1, i16 2, i16 3 } + +; PR31517 - Check that loads which span an aliasing store are not combined. +define i16 @test3() { +; CHECK-LABEL: @test3 + +; CHECK: load i16, i16* +; CHECK: store i16 +; CHECK: ret i16 + + %_tmp9 = getelementptr %rec11, %rec11* @str, i16 0, i32 1 + %_tmp10 = load i16, i16* %_tmp9 + %_tmp12 = getelementptr %rec11, %rec11* @str, i16 0, i32 0 + store i16 %_tmp10, i16* %_tmp12 + %_tmp13 = getelementptr %rec11, %rec11* @str, i16 0, i32 0 + %_tmp14 = load i16, i16* %_tmp13 + %_tmp15 = icmp eq i16 %_tmp14, 3 + %_tmp16 = select i1 %_tmp15, i16 1, i16 0 + ret i16 %_tmp16 +} |
