LoopVectorize: Don't assume pointees are sized

A pointer's pointee might not be sized: the pointee could be a function.

Report this as IK_NoInduction when calculating isInductionVariable.

This fixes PR21508.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@221501 91177308-0d34-0410-b5e6-96231b3b80d8

test/Transforms/LoopVectorize/unsized-pointee-crash.ll

@@ -0,0 +1,24 @@
+; RUN: opt -S -loop-vectorize < %s | FileCheck %s
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+; CHECK-LABEL: @fn1
+define void @fn1() {
+entry:
+  br label %for.body
+
+for.body:
+  %b.05 = phi i32 (...)* [ undef, %entry ], [ %1, %for.body ]
+  %a.04 = phi i32 [ 0, %entry ], [ %inc, %for.body ]
+  %0 = bitcast i32 (...)* %b.05 to i8*
+  %add.ptr = getelementptr i8* %0, i64 1
+  %1 = bitcast i8* %add.ptr to i32 (...)*
+; CHECK:      %[[cst:.*]] = bitcast i32 (...)* {{.*}} to i8*
+; CHECK-NEXT: %[[gep:.*]] = getelementptr i8* %[[cst]], i64 1
+  %inc = add nsw i32 %a.04, 1
+  %exitcond = icmp eq i32 %a.04, 63
+  br i1 %exitcond, label %for.end, label %for.body
+
+for.end:
+  ret void
+}