fix infinite loop in instcombine in the presence of a (malformed) self-referencing select inst.
This can happen as long as the instruction is not reachable. Instcombine does generate these unreachable malformed selects when doing RAUW
llvm-svn: 160874
diff --git a/llvm/test/Transforms/InstCombine/select-crash.ll b/llvm/test/Transforms/InstCombine/select-crash.ll
index 18af152..946ea2b 100644
--- a/llvm/test/Transforms/InstCombine/select-crash.ll
+++ b/llvm/test/Transforms/InstCombine/select-crash.ll
@@ -30,3 +30,20 @@
%sel = select i1 %b, <4 x float> %a, <4 x float> %sub
ret <4 x float> %sel
}
+
+; CHECK: @test3
+define i32 @test3(i1 %bool, i32 %a) {
+entry:
+ %cond = or i1 %bool, true
+ br i1 %cond, label %return, label %xpto
+
+; technically reachable, but this malformed IR may appear as a result of constant propagation
+xpto:
+ %select = select i1 %bool, i32 %a, i32 %select
+ %select2 = select i1 %bool, i32 %select2, i32 %a
+ %sum = add i32 %select, %select2
+ ret i32 %sum
+
+return:
+ ret i32 7
+}