[PATCH] D69627: [SLP]Fix PR43799: Crash on different sizes of GEP indices.

[Alexey Bataev via Phabricator via llvm-commits]

ABataev created this revision.
ABataev added reviewers: RKSimon, spatel.
Herald added a subscriber: hiraditya.
Herald added a project: LLVM.

If the GEP instructions are going to be vectorized, the indices in those
GEP instructions must be of the same type. Otherwise, the compiler may
crash when trying to build the vector constant.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D69627

Files:
  llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp
  llvm/test/Transforms/SLPVectorizer/X86/crash_gep.ll


Index: llvm/test/Transforms/SLPVectorizer/X86/crash_gep.ll
===================================================================
--- llvm/test/Transforms/SLPVectorizer/X86/crash_gep.ll
+++ llvm/test/Transforms/SLPVectorizer/X86/crash_gep.ll
@@ -29,3 +29,26 @@
   store i64 %2, i64* %add.ptr, align 8
   ret i32 undef
 }
+
+define void @PR43799() {
+; CHECK-LABEL: @PR43799(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    br label [[BODY:%.*]]
+; CHECK:       body:
+; CHECK-NEXT:    br label [[BODY]]
+; CHECK:       epilog:
+; CHECK-NEXT:    ret void
+;
+entry:
+  br label %body
+
+body:
+  %p.1.i19 = phi i8* [ undef, %entry ], [ %incdec.ptr.i.7, %body ]
+  %lsr.iv17 = phi i8* [ undef, %entry ], [ %scevgep113.7, %body ]
+  %incdec.ptr.i.7 = getelementptr inbounds i8, i8* undef, i32 1
+  %scevgep113.7 = getelementptr i8, i8* undef, i64 1
+  br label %body
+
+epilog:
+  ret void
+}
Index: llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp
===================================================================
--- llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp
+++ llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp
@@ -4089,7 +4089,16 @@
       std::vector<Value *> OpVecs;
       for (int j = 1, e = cast<GetElementPtrInst>(VL0)->getNumOperands(); j < e;
            ++j) {
-        Value *OpVec = vectorizeTree(E->getOperand(j));
+        ValueList &VL = E->getOperand(j);
+        // Need to cast all elements to the same type before vectorization to
+        // avoid crash.
+        Type *Ty = DL->getIntPtrType(F->getContext());
+        for (Value *&V : VL) {
+          auto *CI = cast<ConstantInt>(V);
+          V = ConstantExpr::getIntegerCast(CI, Ty,
+                                           CI->getValue().isSignBitSet());
+        }
+        Value *OpVec = vectorizeTree(VL);
         OpVecs.push_back(OpVec);
       }
 


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