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| author | Duncan Sands <baldrick@free.fr> | 2008-09-13 12:45:50 +0000 |
|---|---|---|
| committer | Duncan Sands <baldrick@free.fr> | 2008-09-13 12:45:50 +0000 |
| commit | b8ca4ff6439c1543a0c6729cbcd6c70c3be7dc3c (patch) | |
| tree | 465c96bbb30ed24cef5f2e406f3a71e348b47148 | |
| parent | 2aa0e649bfc0157ea08a1ba8f8c9e905ddb581b1 (diff) | |
| download | llvm-b8ca4ff6439c1543a0c6729cbcd6c70c3be7dc3c.tar.gz llvm-b8ca4ff6439c1543a0c6729cbcd6c70c3be7dc3c.tar.bz2 llvm-b8ca4ff6439c1543a0c6729cbcd6c70c3be7dc3c.tar.xz | |
Fix PR2792: treat volatile loads as writing memory somewhere.
Treat stores as reading memory, just to play safe.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@56188 91177308-0d34-0410-b5e6-96231b3b80d8
| -rw-r--r-- | lib/Analysis/IPA/GlobalsModRef.cpp | 14 | ||||
| -rw-r--r-- | test/Analysis/GlobalsModRef/2008-09-13-VolatileRead.ll | 9 |
2 files changed, 20 insertions, 3 deletions
diff --git a/lib/Analysis/IPA/GlobalsModRef.cpp b/lib/Analysis/IPA/GlobalsModRef.cpp index 390a6028eb..74327d5c60 100644 --- a/lib/Analysis/IPA/GlobalsModRef.cpp +++ b/lib/Analysis/IPA/GlobalsModRef.cpp @@ -431,12 +431,20 @@ void GlobalsModRef::AnalyzeCallGraph(CallGraph &CG, Module &M) { for (inst_iterator II = inst_begin(SCC[i]->getFunction()), E = inst_end(SCC[i]->getFunction()); II != E && FunctionEffect != ModRef; ++II) - if (isa<LoadInst>(*II)) + if (isa<LoadInst>(*II)) { FunctionEffect |= Ref; - else if (isa<StoreInst>(*II)) + if (cast<LoadInst>(*II).isVolatile()) + // Volatile loads may have side-effects, so mark them as writing + // memory (for example, a flag inside the processor). + FunctionEffect |= Mod; + } else if (isa<StoreInst>(*II)) { FunctionEffect |= Mod; - else if (isa<MallocInst>(*II) || isa<FreeInst>(*II)) + if (cast<StoreInst>(*II).isVolatile()) + // Treat volatile stores as reading memory somewhere. + FunctionEffect |= Ref; + } else if (isa<MallocInst>(*II) || isa<FreeInst>(*II)) { FunctionEffect |= ModRef; + } if ((FunctionEffect & Mod) == 0) ++NumReadMemFunctions; diff --git a/test/Analysis/GlobalsModRef/2008-09-13-VolatileRead.ll b/test/Analysis/GlobalsModRef/2008-09-13-VolatileRead.ll new file mode 100644 index 0000000000..8ac9637a86 --- /dev/null +++ b/test/Analysis/GlobalsModRef/2008-09-13-VolatileRead.ll @@ -0,0 +1,9 @@ +; RUN: llvm-as < %s | opt -globalsmodref-aa -markmodref | llvm-dis | not grep read +; PR2792 + +@g = global i32 0 ; <i32*> [#uses=1] + +define i32 @f() { + %t = volatile load i32* @g ; <i32> [#uses=1] + ret i32 %t +} |