Implement review feedback from Devang: make use
of mayReadFromMemory and mayWriteToMemory.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@56387 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Transforms/IPO/AddReadAttrs.cpp b/lib/Transforms/IPO/AddReadAttrs.cpp
index 1052e06..8f7fd6e 100644
--- a/lib/Transforms/IPO/AddReadAttrs.cpp
+++ b/lib/Transforms/IPO/AddReadAttrs.cpp
@@ -54,7 +54,7 @@
Function *F = SCC[i]->getFunction();
if (F == 0)
- // May write memory.
+ // External node - may write memory.
return false;
if (F->doesNotAccessMemory())
@@ -72,34 +72,19 @@
continue;
}
- // Scan the function body for explicit loads and stores, or calls to
- // functions that may read or write memory.
+ // Scan the function body for instructions that may read or write memory.
for (inst_iterator II = inst_begin(F), E = inst_end(F); II != E; ++II) {
- Instruction *I = &*II;
- if (LoadInst *LI = dyn_cast<LoadInst>(I)) {
- if (LI->isVolatile())
- // Volatile loads may have side-effects, so treat them as writing
- // memory.
- return false;
- ReadsMemory = true;
- } else if (isa<StoreInst>(I) || isa<MallocInst>(I) || isa<FreeInst>(I)) {
- // Writes memory.
+ CallSite CS = CallSite::get(&*II);
+
+ // Ignore calls to functions in the same SCC.
+ if (CS.getInstruction() &&
+ std::find(SCC.begin(), SCC.end(), CG[CS.getCalledFunction()]) !=
+ SCC.end())
+ continue;
+
+ if (II->mayWriteToMemory())
return false;
- } else if (isa<CallInst>(I) || isa<InvokeInst>(I)) {
- CallSite CS(I);
-
- if (std::find(SCC.begin(), SCC.end(), CG[CS.getCalledFunction()]) !=
- SCC.end())
- // The callee is inside our current SCC - ignore it.
- continue;
-
- if (!CS.onlyReadsMemory())
- // May write memory.
- return false;
-
- if (!CS.doesNotAccessMemory())
- ReadsMemory = true;
- }
+ ReadsMemory |= II->mayReadFromMemory();
}
}