From 9a324ecb42f69791d49bc8e62e935aec75b5e920 Mon Sep 17 00:00:00 2001
From: Andrew Kelley <andrew@ziglang.org>
Date: Mon, 10 Jun 2019 19:11:34 -0400
Subject: result loc semantics for loading packed struct pointer to packed
 struct

```zig
export fn entry() void {
    var x = foo();
    var ptr = &x.b;
    var y = ptr.*;
}
const Foo = packed struct {
    a: u24 = 1,
    b: Bar = Bar{},
};

const Bar = packed struct {
    a: u4 = 2,
    b: u4 = 3,
};
```

```llvm
define void @entry() #2 !dbg !35 {
Entry:
  %x = alloca %Foo, align 1
  %ptr = alloca i32*, align 8
  %y = alloca %Bar, align 1
  call fastcc void @foo(%Foo* sret %x), !dbg !55
  call void @llvm.dbg.declare(metadata %Foo* %x, metadata !39, metadata !DIExpression()), !dbg !56
  %0 = getelementptr inbounds %Foo, %Foo* %x, i32 0, i32 0, !dbg !57
  store i32* %0, i32** %ptr, align 8, !dbg !57
  call void @llvm.dbg.declare(metadata i32** %ptr, metadata !51, metadata !DIExpression()), !dbg !58
  %1 = load i32*, i32** %ptr, align 8, !dbg !59
  %2 = load i32, i32* %1, align 1, !dbg !60
  %3 = lshr i32 %2, 24, !dbg !60
  %4 = trunc i32 %3 to i8, !dbg !60
  %5 = bitcast %Bar* %y to i8*, !dbg !60
  store i8 %4, i8* %5, !dbg !60
  call void @llvm.dbg.declare(metadata %Bar* %y, metadata !54, metadata !DIExpression()), !dbg !61
  ret void, !dbg !62
}
```
---
 src/codegen.cpp | 9 +++------
 1 file changed, 3 insertions(+), 6 deletions(-)

(limited to 'src/codegen.cpp')

diff --git a/src/codegen.cpp b/src/codegen.cpp
index d84bcd1327..994194c5eb 100644
--- a/src/codegen.cpp
+++ b/src/codegen.cpp
@@ -3376,13 +3376,13 @@ static LLVMValueRef ir_render_load_ptr(CodeGen *g, IrExecutable *executable, IrI
     LLVMValueRef shifted_value = LLVMBuildLShr(g->builder, containing_int, shift_amt_val, "");
 
     if (handle_is_ptr(child_type)) {
-        assert(instruction->tmp_ptr != nullptr);
+        LLVMValueRef result_loc = ir_llvm_value(g, instruction->result_loc);
         LLVMTypeRef same_size_int = LLVMIntType(size_in_bits);
         LLVMValueRef truncated_int = LLVMBuildTrunc(g->builder, shifted_value, same_size_int, "");
-        LLVMValueRef bitcasted_ptr = LLVMBuildBitCast(g->builder, instruction->tmp_ptr,
+        LLVMValueRef bitcasted_ptr = LLVMBuildBitCast(g->builder, result_loc,
                                                       LLVMPointerType(same_size_int, 0), "");
         LLVMBuildStore(g->builder, truncated_int, bitcasted_ptr);
-        return instruction->tmp_ptr;
+        return result_loc;
     }
 
     if (child_type->id == ZigTypeIdFloat) {
@@ -6838,9 +6838,6 @@ static void do_code_gen(CodeGen *g) {
                 slot = &ref_instruction->tmp_ptr;
                 assert(instruction->value.type->id == ZigTypeIdPointer);
                 slot_type = instruction->value.type->data.pointer.child_type;
-            } else if (instruction->id == IrInstructionIdLoadPtrGen) {
-                IrInstructionLoadPtrGen *load_ptr_inst = (IrInstructionLoadPtrGen *)instruction;
-                slot = &load_ptr_inst->tmp_ptr;
             } else if (instruction->id == IrInstructionIdVectorToArray) {
                 IrInstructionVectorToArray *vector_to_array_instruction = (IrInstructionVectorToArray *)instruction;
                 alignment_bytes = get_abi_alignment(g, vector_to_array_instruction->vector->value.type);
-- 
cgit v1.2.3