From 2a5c622e65a07db95859beabf46f36d3a62c785a Mon Sep 17 00:00:00 2001
From: LemonBoy <thatlemon@gmail.com>
Date: Tue, 7 Jan 2020 19:58:31 +0100
Subject: [PATCH] Fix crash with unresolved loc

Fixes #4099
---
 src/ir.cpp                       | 14 +++++++-------
 test/stage1/behavior/bitcast.zig | 17 +++++++++++++++++
 2 files changed, 24 insertions(+), 7 deletions(-)

diff --git a/src/ir.cpp b/src/ir.cpp
index 5fae82ceeb..e841da35d0 100644
--- a/src/ir.cpp
+++ b/src/ir.cpp
@@ -19278,7 +19278,7 @@ static IrInstruction *ir_analyze_instruction_phi(IrAnalyze *ira, IrInstructionPh
         return new_incoming_values.at(0);
     }
 
-    ZigType *resolved_type;
+    ZigType *resolved_type = nullptr;
     if (peer_parent != nullptr) {
         bool peer_parent_has_type;
         if ((err = ir_result_has_type(ira, peer_parent->parent, &peer_parent_has_type)))
@@ -19288,23 +19288,23 @@ static IrInstruction *ir_analyze_instruction_phi(IrAnalyze *ira, IrInstructionPh
                 resolved_type = ira->explicit_return_type;
             } else if (peer_parent->parent->id == ResultLocIdCast) {
                 resolved_type = ir_resolve_type(ira, peer_parent->parent->source_instruction->child);
-                if (type_is_invalid(resolved_type))
-                    return ira->codegen->invalid_instruction;
-            } else {
+            } else if (peer_parent->parent->resolved_loc) {
                 ZigType *resolved_loc_ptr_type = peer_parent->parent->resolved_loc->value->type;
                 ir_assert(resolved_loc_ptr_type->id == ZigTypeIdPointer, &phi_instruction->base);
                 resolved_type = resolved_loc_ptr_type->data.pointer.child_type;
             }
-            goto skip_resolve_peer_types;
+
+            if (resolved_type != nullptr && type_is_invalid(resolved_type))
+                return ira->codegen->invalid_instruction;
         }
     }
-    {
+
+    if (resolved_type == nullptr) {
         resolved_type = ir_resolve_peer_types(ira, phi_instruction->base.source_node, nullptr,
                 new_incoming_values.items, new_incoming_values.length);
         if (type_is_invalid(resolved_type))
             return ira->codegen->invalid_instruction;
     }
-skip_resolve_peer_types:
 
     switch (type_has_one_possible_value(ira->codegen, resolved_type)) {
     case OnePossibleValueInvalid:
diff --git a/test/stage1/behavior/bitcast.zig b/test/stage1/behavior/bitcast.zig
index 87b69d0e25..fe3dd6902d 100644
--- a/test/stage1/behavior/bitcast.zig
+++ b/test/stage1/behavior/bitcast.zig
@@ -150,3 +150,20 @@ test "comptime bitcast used in expression has the correct type" {
 test "bitcast result to _" {
     _ = @bitCast(u8, @as(i8, 1));
 }
+
+test "nested bitcast" {
+    const S = struct {
+        fn moo(x: isize) void {
+            @import("std").testing.expectEqual(@intCast(isize, 42), x);
+        }
+
+        fn foo(x: isize) void {
+            @This().moo(
+                @bitCast(isize, if (x != 0) @bitCast(usize, x) else @bitCast(usize, x)),
+            );
+        }
+    };
+
+    S.foo(42);
+    comptime S.foo(42);
+}