[SLP]Fix PR58863: Mask index beyond mask size for non-power-2 insertelement analysis.

[ABataev]

Summary

Need to check if the insertelement mask size is reached during cost analysis to avoid compiler crash.

[RKSimon]

llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp

6705–6706

Is this any better?

Mask[I] = ((I >= InMask.size()) || InMask.test(I)) ? UndefMaskElem : I;

[ABataev]

Address comment

[RKSimon]

LGTM

llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp

if (!InMask.all() && NumScalars != NumElts && !IsWholeSubvector) {
       } else {
         for (unsigned I = 0, End = OffsetBeg - Offset; I < End; ++I)
           Mask[I] = InMask.test(I) ? UndefMaskElem : I;
         for (unsigned I = OffsetBeg - Offset, End = OffsetEnd - Offset;
              I <= End; ++I)
           if (Mask[I] != UndefMaskElem)
             Mask[I] = I + VecSz;
         for (unsigned I = OffsetEnd + 1 - Offset; I < VecSz; ++I)
-          Mask[I] = InMask.test(I) ? UndefMaskElem : I;
+          Mask[I] =
+              ((I >= InMask.size()) || InMask.test(I)) ? UndefMaskElem : I;
         Cost += TTI->getShuffleCost(TTI::SK_PermuteTwoSrc, InsertVecTy, Mask);
       }
     }
     return Cost;
   }
   case Instruction::ZExt:
   case Instruction::SExt:
   case Instruction::FPToUI:

llvm/test/Transforms/SLPVectorizer/slp-non-pow-2-insertelement.ll

+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
+; RUN: opt -S -passes=slp-vectorizer < %s | FileCheck %s
+
+define void @PR58863() {
+; CHECK-LABEL: @PR58863(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    [[MUL_I:%.*]] = fmul float poison, poison
+; CHECK-NEXT:    [[MUL11_I:%.*]] = fmul float poison, poison
+; CHECK-NEXT:    [[I:%.*]] = insertelement <3 x float> <float poison, float 0.000000e+00, float poison>, float [[MUL_I]], i64 0
+; CHECK-NEXT:    [[I1:%.*]] = insertelement <3 x float> [[I]], float [[MUL11_I]], i64 2
+; CHECK-NEXT:    ret void
+;
+entry:
+  %mul.i = fmul float poison, poison
+  %mul11.i = fmul float poison, poison
+  %i = insertelement <3 x float> <float poison, float 0.000000e+00, float poison>, float %mul.i, i64 0
+  %i1 = insertelement <3 x float> %i, float %mul11.i, i64 2
+  ret void
+}