codegen: fix PhiNode incoming basic block

Sometimes doing codegen will change the basic block, resulting in our
making the phi node from the wrong branch. Instead be careful to use
exactly the basic block into which we just put the branch.

src/cgutils.cpp

@@ -944,9 +944,11 @@ static jl_cgval_t emit_typeof(jl_codectx_t &ctx, const jl_cgval_t &p)
             ctx.builder.SetInsertPoint(boxBB);
             auto boxTy = emit_typeof(ctx, p.Vboxed);
             ctx.builder.CreateBr(mergeBB);
+            boxBB = ctx.builder.GetInsertBlock(); // could have changed
             ctx.builder.SetInsertPoint(unboxBB);
             auto unboxTy = emit_unboxty();
             ctx.builder.CreateBr(mergeBB);
+            unboxBB = ctx.builder.GetInsertBlock(); // could have changed
             ctx.builder.SetInsertPoint(mergeBB);
             auto phi = ctx.builder.CreatePHI(T_prjlvalue, 2);
             phi->addIncoming(boxTy, boxBB);
@@ -1012,6 +1014,7 @@ static Value *emit_sizeof(jl_codectx_t &ctx, const jl_cgval_t &p)
             Value *datatype = emit_typeof(p.V);
             Value *dyn_size = emit_datatype_size(ctx, datatype);
             ctx.builder.CreateBr(postBB);
+            dynloadBB = ctx.builder.GetInsertBlock(); // could have changed
             ctx.builder.SetInsertPoint(postBB);
             PHINode *sizeof_merge = ctx.builder.CreatePHI(T_int32, 2);
             sizeof_merge->addIncoming(dyn_size, dynloadBB);
@@ -1207,6 +1210,7 @@ static std::pair<Value*, bool> emit_isa(jl_codectx_t &ctx, const jl_cgval_t &x,
                 Value *istype_boxed = ctx.builder.CreateICmpEQ(emit_typeof(ctx, x.Vboxed),
                     maybe_decay_untracked(literal_pointer_val(ctx, intersected_type)));
                 ctx.builder.CreateBr(postBB);
+                isaBB = ctx.builder.GetInsertBlock(); // could have changed
                 ctx.builder.SetInsertPoint(postBB);
                 PHINode *istype = ctx.builder.CreatePHI(T_int1, 2);
                 istype->addIncoming(ConstantInt::get(T_int1, 0), currBB);
@@ -2405,15 +2409,18 @@ static Value *box_union(jl_codectx_t &ctx, const jl_cgval_t &vinfo, const SmallB
                         init_bits_cgval(ctx, box, vinfo_r, jl_is_mutable(jt) ? tbaa_mutab : tbaa_immut);
                     }
                 }
-                box_merge->addIncoming(maybe_decay_untracked(box), tempBB);
+                box = maybe_decay_untracked(box);
+                tempBB = ctx.builder.GetInsertBlock(); // could have changed
+                box_merge->addIncoming(box, tempBB);
                 ctx.builder.CreateBr(postBB);
             },
             vinfo.typ,
             counter);
     ctx.builder.SetInsertPoint(defaultBB);
     if (skip.size() > 0) {
         assert(skip[0]);
-        box_merge->addIncoming(maybe_decay_untracked(V_null), defaultBB);
+        Value *box = maybe_decay_untracked(V_null);
+        box_merge->addIncoming(box, defaultBB);
         ctx.builder.CreateBr(postBB);
     }
     else if (!vinfo.Vboxed) {

src/codegen.cpp

@@ -1739,7 +1739,9 @@ static Value *emit_bitsunion_compare(jl_codectx_t &ctx, const jl_cgval_t &arg1,
             switchInst->addCase(ConstantInt::get(T_int8, idx), tempBB);
             jl_cgval_t sel_arg1(arg1, (jl_value_t*)jt, NULL);
             jl_cgval_t sel_arg2(arg2, (jl_value_t*)jt, NULL);
-            phi->addIncoming(emit_bits_compare(ctx, sel_arg1, sel_arg2), tempBB);
+            Value *cmp = emit_bits_compare(ctx, sel_arg1, sel_arg2);
+            tempBB = ctx.builder.GetInsertBlock(); // could have changed
+            phi->addIncoming(cmp, tempBB);
             ctx.builder.CreateBr(postBB);
         },
         arg1.typ,
@@ -1928,6 +1930,7 @@ static Value *emit_f_is(jl_codectx_t &ctx, const jl_cgval_t &arg1, const jl_cgva
         Value *bitcmp = emit_bits_compare(ctx,
                 jl_cgval_t(arg1, typ, NULL),
                 jl_cgval_t(arg2, typ, NULL));
+        isaBB = ctx.builder.GetInsertBlock(); // might have changed
         ctx.builder.CreateBr(postBB);
         ctx.builder.SetInsertPoint(postBB);
         PHINode *cmp = ctx.builder.CreatePHI(T_int1, 2);
@@ -2085,6 +2088,7 @@ static bool emit_builtin_call(jl_codectx_t &ctx, jl_cgval_t *ret, jl_value_t *f,
                     ctx.builder.SetInsertPoint(inBB);
                     Value *v_sz = emit_arraysize(ctx, ary, idx_dyn);
                     ctx.builder.CreateBr(ansBB);
+                    inBB = ctx.builder.GetInsertBlock(); // could have changed
                     ctx.f->getBasicBlockList().push_back(ansBB);
                     ctx.builder.SetInsertPoint(ansBB);
                     PHINode *result = ctx.builder.CreatePHI(T_size, 2);
@@ -4198,6 +4202,7 @@ static Function* gen_cfun_wrapper(
                 ctx.builder.CreateBr(afterBB);
                 ctx.builder.SetInsertPoint(unboxedBB);
                 Value *p3 = emit_new_bits(ctx, runtime_dt, val);
+                unboxedBB = ctx.builder.GetInsertBlock(); // could have changed
                 ctx.builder.CreateBr(afterBB);
                 ctx.builder.SetInsertPoint(afterBB);
                 PHINode *p = ctx.builder.CreatePHI(T_prjlvalue, 3);

src/intrinsics.cpp

@@ -847,8 +847,9 @@ static jl_cgval_t emit_ifelse(jl_codectx_t &ctx, jl_cgval_t c, jl_cgval_t x, jl_
                     tindex = compute_tindex_unboxed(ctx, x, rt_hint);
                 }
                 tindex = ctx.builder.CreateOr(tindex, ConstantInt::get(T_int8, 0x80));
-                ret->addIncoming(tindex, compute);
+                compute = ctx.builder.GetInsertBlock(); // could have changed
                 ctx.builder.CreateBr(post);
+                ret->addIncoming(tindex, compute);
                 ctx.builder.SetInsertPoint(post);
                 ctx.builder.Insert(ret);
                 tindex = ret;