[VectorUtils] API for VFShape, update VFInfo.

Summary:
This patch introduces an API to build and modify vector shapes.

The validity of a VFShape can be checked with the
`hasValidParameterList` method, which is also run in an assertion each
time a VFShape is modified.

The field VFISAKind has been moved to VFInfo under the assumption that
different ISAs can map to the same VFShape (as it can be in the case
of vector extensions with the same registers size, for example AVX and
AVX2).

Reviewers: sdesmalen, jdoerfert, simoll, hsaito

Subscribers: hiraditya, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D70513

1 files changed, 44 insertions, 0 deletions

diff --git a/llvm/lib/Analysis/VectorUtils.cpp b/llvm/lib/Analysis/VectorUtils.cpp
index 44043bd582c..c45ab941a14 100644
--- a/llvm/lib/Analysis/VectorUtils.cpp
+++ b/llvm/lib/Analysis/VectorUtils.cpp
@@ -1182,3 +1182,47 @@ void VFABI::getVectorVariantNames(
     VariantMappings.push_back(S);
   }
 }
+
+bool VFShape::hasValidParameterList() const {
+  for (unsigned Pos = 0, NumParams = Parameters.size(); Pos < NumParams;
+       ++Pos) {
+    assert(Parameters[Pos].ParamPos == Pos && "Broken parameter list.");
+
+    switch (Parameters[Pos].ParamKind) {
+    default: // Nothing to check.
+      break;
+    case VFParamKind::OMP_Linear:
+    case VFParamKind::OMP_LinearRef:
+    case VFParamKind::OMP_LinearVal:
+    case VFParamKind::OMP_LinearUVal:
+      // Compile time linear steps must be non-zero.
+      if (Parameters[Pos].LinearStepOrPos == 0)
+        return false;
+      break;
+    case VFParamKind::OMP_LinearPos:
+    case VFParamKind::OMP_LinearRefPos:
+    case VFParamKind::OMP_LinearValPos:
+    case VFParamKind::OMP_LinearUValPos:
+      // The runtime linear step must be referring to some other
+      // parameters in the signature.
+      if (Parameters[Pos].LinearStepOrPos >= int(NumParams))
+        return false;
+      // The linear step parameter must be marked as uniform.
+      if (Parameters[Parameters[Pos].LinearStepOrPos].ParamKind !=
+          VFParamKind::OMP_Uniform)
+        return false;
+      // The linear step parameter can't point at itself.
+      if (Parameters[Pos].LinearStepOrPos == int(Pos))
+        return false;
+      break;
+    case VFParamKind::GlobalPredicate:
+      // The global predicate must be the unique. Can be placed anywhere in the
+      // signature.
+      for (unsigned NextPos = Pos + 1; NextPos < NumParams; ++NextPos)
+        if (Parameters[NextPos].ParamKind == VFParamKind::GlobalPredicate)
+          return false;
+      break;
+    }
+  }
+  return true;
+}