Merge pull request #10487 from gita-omr/v0.22.0-release

Disable AutoSIMD for problematic IV increment
eclipse-openj9 · Aug 28, 2020 · 53e0b10 · 53e0b10
2 parents 88c59f8 + b613b24
commit 53e0b10
Showing 1 changed file with 14 additions and 0 deletions.
diff --git a/runtime/compiler/optimizer/SPMDParallelizer.cpp b/runtime/compiler/optimizer/SPMDParallelizer.cpp
@@ -386,6 +386,20 @@ bool TR_SPMDKernelParallelizer::visitTreeTopToSIMDize(TR::TreeTop *tt, TR_SPMDKe
                int32_t pivStride = INVALID_STRIDE;
                bool isAffine = isAffineAccess(comp, node->getFirstChild(), loop, piv, pivStride);
 
+               // if the induction variable is not incremented after the soon to be vectorized instructions, then we bail out (see: openj9/issues/9331)
+               if (isCheckMode)
+                  {
+                  if (!(tt->getNextTreeTop()->getNode()->getOpCode().isBooleanCompare() &&
+                      tt->getNextTreeTop()->getNode()->getOpCode().isBranch() &&
+                      hasPIV(tt->getNextTreeTop()->getNode(), piv)) ||
+                      tt->getNextTreeTop()->getNextTreeTop()->getNode()->getOpCodeValue() != TR::BBEnd)
+                     {
+                     traceMsg(comp, "   Induction variable may be incremented before vectorized operations, "
+                      "this may cause functionally incorrect result. Vectorization not performed. see: openj9/issues/9331.\n");
+                     return false;
+                     }
+                  }
+
                // if this is transformation mode and this PIV is used by a vectorized expression and satisfies
                // affine access conditions, duplicate the trees to create a vectorized loop increment
                // for the vectorized version of the PIV