Don't try to pull vector bitcasts that change the number of elements through

a select. A vector select is pairwise on each element so we'd need a new
condition with the right number of elements to select on. Fixes PR8994.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@123963 91177308-0d34-0410-b5e6-96231b3b80d8

test/Transforms/InstCombine/select.ll

@@ -689,3 +689,14 @@ define i64 @test50(i32 %a) nounwind {
 ; CHECK-NEXT: %min = select i1 %is_a_nonpositive, i64 %a_ext, i64 2
 ; CHECK-NEXT: ret i64 %min
 }
+
+; PR8994
+
+; Theis select instruction can't be eliminated because trying to do so would
+; change the number of vector elements. This used to assert.
+define i48 @test51(<3 x i1> %icmp, <3 x i16> %tmp) {
+  %select = select <3 x i1> %icmp, <3 x i16> zeroinitializer, <3 x i16> %tmp
+; CHECK: select <3 x i1>
+  %tmp2 = bitcast <3 x i16> %select to i48
+  ret i48 %tmp2
+}