Fix interpreter_exec.jl test

This test was supposed to check that we correctly handled PhiNodes in uninferred
code in both the interpreter and the compiler. However, the compiler path wasn't
actually exercised, because the `inferred=true` part of this forced it to be skipped.
Drop that and fix the exposed issues in the compiler where we didn't handle PhiNodes
properly.

Author: Keno

base/compiler/abstractinterpretation.jl

@@ -3304,6 +3304,10 @@ function typeinf_local(interp::AbstractInterpreter, frame::InferenceState)
             end
             if rt === Bottom
                 ssavaluetypes[currpc] = Bottom
+                # Special case: Union typed PhiNodes do not error (but must also be unused)
+                if isa(stmt, PhiNode)
+                    continue
+                end
                 @goto find_next_bb
             end
             if changes !== nothing

base/compiler/optimize.jl

@@ -1085,7 +1085,7 @@ function convert_to_ircode(ci::CodeInfo, sv::OptimizationState)
             idx += 1
             prevloc = codeloc
         end
-        if ssavaluetypes[idx] === Union{} && !(oldidx in sv.unreachable)
+        if ssavaluetypes[idx] === Union{} && !(oldidx in sv.unreachable) && !isa(code[idx], PhiNode)
             # We should have converted any must-throw terminators to an equivalent w/o control-flow edges
             @assert !isterminator(code[idx])
 

test/compiler/interpreter_exec.jl

@@ -20,10 +20,9 @@ let m = Meta.@lower 1 + 1
         ReturnNode(SSAValue(6)),
     ]
     nstmts = length(src.code)
-    src.ssavaluetypes = Any[ Any for _ = 1:nstmts ]
+    src.ssavaluetypes = nstmts
     src.ssaflags = fill(UInt8(0x00), nstmts)
     src.codelocs = fill(Int32(1), nstmts)
-    src.inferred = true
     Core.Compiler.verify_ir(Core.Compiler.inflate_ir(src))
     global test29262 = true
     @test :a === @eval $m
@@ -61,13 +60,13 @@ let m = Meta.@lower 1 + 1
         ReturnNode(SSAValue(18)),
     ]
     nstmts = length(src.code)
-    src.ssavaluetypes = Any[ Any for _ = 1:nstmts ]
+    src.ssavaluetypes = nstmts
     src.ssaflags = fill(UInt8(0x00), nstmts)
     src.codelocs = fill(Int32(1), nstmts)
-    src.inferred = true
     Core.Compiler.verify_ir(Core.Compiler.inflate_ir(src))
     global test29262 = true
     @test (:b, :a, :c, :c) === @eval $m
+    src.ssavaluetypes = nstmts
     global test29262 = false
     @test (:b, :a, :c, :b) === @eval $m
 end
@@ -98,10 +97,9 @@ let m = Meta.@lower 1 + 1
         ReturnNode(SSAValue(11)),
     ]
     nstmts = length(src.code)
-    src.ssavaluetypes = Any[ Any for _ = 1:nstmts ]
+    src.ssavaluetypes = nstmts
     src.ssaflags = fill(UInt8(0x00), nstmts)
     src.codelocs = fill(Int32(1), nstmts)
-    src.inferred = true
     Core.Compiler.verify_ir(Core.Compiler.inflate_ir(src))
     global test29262 = true
     @test :a === @eval $m