[PATCH] D86989: [InstCombine] Fix a couple crahses with extractelement on a scalable vector.

[Eli Friedman via Phabricator via llvm-commits]

efriedma created this revision.
efriedma added reviewers: ctetreau, sdesmalen, spatel, lebedev.ri, david-arm, fpetrogalli.
Herald added a subscriber: hiraditya.
Herald added a project: LLVM.
efriedma requested review of this revision.

Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D86989

Files:
  llvm/lib/Analysis/ValueTracking.cpp
  llvm/lib/Transforms/InstCombine/InstCombineCasts.cpp
  llvm/test/Transforms/InstCombine/vscale_extractelement.ll


Index: llvm/test/Transforms/InstCombine/vscale_extractelement.ll
===================================================================
--- llvm/test/Transforms/InstCombine/vscale_extractelement.ll
+++ llvm/test/Transforms/InstCombine/vscale_extractelement.ll
@@ -146,3 +146,27 @@
   %4 = insertelement <vscale x 4 x i32> %3, i32 %vec.e3, i32 3
   ret <vscale x 4 x i32> %4
 }
+
+define i32 @bitcast_of_extractelement( <vscale x 2 x float> %d) {
+; CHECK-LABEL: @bitcast_of_extractelement(
+; CHECK-NEXT:    [[BC:%.*]] = bitcast <vscale x 2 x float> [[D:%.*]] to <vscale x 2 x i32>
+; CHECK-NEXT:    [[CAST:%.*]] = extractelement <vscale x 2 x i32> [[BC]], i32 0
+; CHECK-NEXT:    ret i32 [[CAST]]
+;
+  %ext = extractelement <vscale x 2 x float> %d, i32 0
+  %cast = bitcast float %ext to i32
+  ret i32 %cast
+}
+
+define i1 @extractelement_is_zero(<vscale x 2 x i32> %d, i1 %b, i32 %z) {
+; CHECK-LABEL: @extractelement_is_zero(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    [[EXT:%.*]] = extractelement <vscale x 2 x i32> [[D:%.*]], i32 0
+; CHECK-NEXT:    [[BB:%.*]] = icmp eq i32 [[EXT]], 0
+; CHECK-NEXT:    ret i1 [[BB]]
+;
+entry:
+  %ext = extractelement <vscale x 2 x i32> %d, i32 0
+  %bb = icmp eq i32 %ext, 0
+  ret i1 %bb
+}
Index: llvm/lib/Transforms/InstCombine/InstCombineCasts.cpp
===================================================================
--- llvm/lib/Transforms/InstCombine/InstCombineCasts.cpp
+++ llvm/lib/Transforms/InstCombine/InstCombineCasts.cpp
@@ -2222,8 +2222,7 @@
   if (!VectorType::isValidElementType(DestType))
     return nullptr;
 
-  unsigned NumElts = ExtElt->getVectorOperandType()->getNumElements();
-  auto *NewVecType = FixedVectorType::get(DestType, NumElts);
+  auto *NewVecType = VectorType::get(DestType, ExtElt->getVectorOperandType());
   auto *NewBC = IC.Builder.CreateBitCast(ExtElt->getVectorOperand(),
                                          NewVecType, "bc");
   return ExtractElementInst::Create(NewBC, ExtElt->getIndexOperand());
Index: llvm/lib/Analysis/ValueTracking.cpp
===================================================================
--- llvm/lib/Analysis/ValueTracking.cpp
+++ llvm/lib/Analysis/ValueTracking.cpp
@@ -2568,11 +2568,13 @@
     const Value *Vec = EEI->getVectorOperand();
     const Value *Idx = EEI->getIndexOperand();
     auto *CIdx = dyn_cast<ConstantInt>(Idx);
-    unsigned NumElts = cast<FixedVectorType>(Vec->getType())->getNumElements();
-    APInt DemandedVecElts = APInt::getAllOnesValue(NumElts);
-    if (CIdx && CIdx->getValue().ult(NumElts))
-      DemandedVecElts = APInt::getOneBitSet(NumElts, CIdx->getZExtValue());
-    return isKnownNonZero(Vec, DemandedVecElts, Depth, Q);
+    if (auto *VecTy = dyn_cast<FixedVectorType>(Vec->getType())) {
+      unsigned NumElts = VecTy->getNumElements();
+      APInt DemandedVecElts = APInt::getAllOnesValue(NumElts);
+      if (CIdx && CIdx->getValue().ult(NumElts))
+        DemandedVecElts = APInt::getOneBitSet(NumElts, CIdx->getZExtValue());
+      return isKnownNonZero(Vec, DemandedVecElts, Depth, Q);
+    }
   }
 
   KnownBits Known(BitWidth);


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