[PATCH] D48128: [ARM] Parallel DSP IR Pass

[Eli Friedman via Phabricator via llvm-commits]

efriedma added inline comments.


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Comment at: lib/Target/ARM/ARMParallelDSP.cpp:259
+    LLVM_DEBUG(dbgs() << "OK: loads are consecutive.\n");
+    return true;
+  }
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SjoerdMeijer wrote:
> efriedma wrote:
> > Do you need to check that the memory isn't modified between the two loads?
> Yes, we check this a bit earlier with AreNoAliases() in CreateParallelMACPairs().
> The store and alias checks are tested in tests smlad6.ll and smlad7.ll, but please let me know if I've missed something here.
The AreNoAliases check only looks for "store" instructions; other instructions can write to memory.  Maybe you want AliasAnalysis::getModRefInfo()?


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Comment at: lib/Target/ARM/ARMParallelDSP.cpp:254
+
+  if (Ld0->isVolatile() || Ld1->isVolatile()) {
+    LLVM_DEBUG(dbgs() << "No, not touching volatile loads\n");
----------------
Please check isSimple() instead.


https://reviews.llvm.org/D48128