[clang] [clang][CodeGen] Additional fixes for #114062 (PR #128166)

[Matt Arsenault via cfe-commits]

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@@ -0,0 +1,32 @@
+// NOTE: Assertions have been autogenerated by utils/update_cc_test_checks.py UTC_ARGS: --version 5
+// RUN: %clang_cc1 -triple amdgcn-amd-amdhsa-gnu -target-cpu gfx900 -emit-llvm -o - %s | FileCheck %s
+
+struct X { int z[17]; };
+
+// CHECK-LABEL: define dso_local void @_Z3foocc(
+// CHECK-SAME: ptr addrspace(5) dead_on_unwind noalias writable sret([[STRUCT_X:%.*]]) align 4 [[AGG_RESULT:%.*]], i8 noundef signext [[X:%.*]], i8 noundef signext [[Y:%.*]]) #[[ATTR0:[0-9]+]] {
+// CHECK-NEXT:  [[ENTRY:.*:]]
+// CHECK-NEXT:    [[X_ADDR:%.*]] = alloca i8, align 1, addrspace(5)
+// CHECK-NEXT:    [[Y_ADDR:%.*]] = alloca i8, align 1, addrspace(5)
+// CHECK-NEXT:    [[X_ADDR_ASCAST:%.*]] = addrspacecast ptr addrspace(5) [[X_ADDR]] to ptr
+// CHECK-NEXT:    [[Y_ADDR_ASCAST:%.*]] = addrspacecast ptr addrspace(5) [[Y_ADDR]] to ptr
+// CHECK-NEXT:    store i8 [[X]], ptr [[X_ADDR_ASCAST]], align 1
+// CHECK-NEXT:    store i8 [[Y]], ptr [[Y_ADDR_ASCAST]], align 1
+// CHECK-NEXT:    [[TMP0:%.*]] = load i8, ptr [[X_ADDR_ASCAST]], align 1
+// CHECK-NEXT:    [[AGG_RESULT_ASCAST:%.*]] = addrspacecast ptr addrspace(5) [[AGG_RESULT]] to ptr
+// CHECK-NEXT:    [[ADD_PTR:%.*]] = getelementptr inbounds i8, ptr [[AGG_RESULT_ASCAST]], i64 1
+// CHECK-NEXT:    store i8 [[TMP0]], ptr [[ADD_PTR]], align 1
+// CHECK-NEXT:    [[TMP1:%.*]] = load i8, ptr [[Y_ADDR_ASCAST]], align 1
+// CHECK-NEXT:    [[AGG_RESULT_ASCAST1:%.*]] = addrspacecast ptr addrspace(5) [[AGG_RESULT]] to ptr
+// CHECK-NEXT:    [[ADD_PTR2:%.*]] = getelementptr inbounds i8, ptr [[AGG_RESULT_ASCAST1]], i64 2
+// CHECK-NEXT:    store i8 [[TMP1]], ptr [[ADD_PTR2]], align 1
+// CHECK-NEXT:    ret void
+//
+X foo(char x, char y) {
+    X r;
+
+    *(((char*)&r) + 1) = x;
+    *(reinterpret_cast<char*>(&r) + 2) = y;
+
+    return r;
+}
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arsenm wrote:

Does the analogous byval / byref case need to be tested? 

https://github.com/llvm/llvm-project/pull/128166