[PATCH] D71743: [ARM][MVE] Enable masked gathers from vector of pointers

[Dave Green via Phabricator via llvm-commits]

dmgreen added inline comments.


================
Comment at: llvm/lib/Target/ARM/ARMTargetTransformInfo.cpp:547
+  // Do only allow non-extending v4i32 gathers for now
+  return NumElements == 4 && ElemSize == 32 && Alignment == 4;
+}
----------------
Alignment >= 4


================
Comment at: llvm/lib/Target/ARM/ARMTargetTransformInfo.cpp:552
+                                            bool &ModifiedDT) const {
+  if (!EnableMaskedGatherScatters)
+    return false;
----------------
We should add the "ST->hasMVEIntegerOps()" check here too.


================
Comment at: llvm/lib/Target/ARM/ARMTargetTransformInfo.cpp:568
+                        Ty->getScalarSizeInBits(), Alignment))
+    return false;
+
----------------
I think it would be useful to add debug comments for what is happening, which will become more useful as we add more variants in here. Especially around why and where we have decided not to transform.


================
Comment at: llvm/lib/Target/ARM/ARMTargetTransformInfo.cpp:598
+
+  if (Load && !isa<UndefValue>(PassThru) && !match(PassThru, m_Zero())) {
+    Load = Builder.CreateSelect(Mask, Load, PassThru);
----------------
You can drop the brackets if there is only a single statement in the if block.


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  https://reviews.llvm.org/D71743/new/

https://reviews.llvm.org/D71743