[CIR][CodeGen][Builtin] Implement bcopy and __builtin_bcopy (#1855)

Closes #1816

Author: bruteforceboy

clang/lib/CIR/CodeGen/CIRGenBuiltin.cpp

@@ -1716,8 +1716,19 @@ RValue CIRGenFunction::emitBuiltinExpr(const GlobalDecl GD, unsigned BuiltinID,
     llvm_unreachable("BIbzero like NYI");
 
   case Builtin::BIbcopy:
-  case Builtin::BI__builtin_bcopy:
-    llvm_unreachable("BIbcopy like NYI");
+  case Builtin::BI__builtin_bcopy: {
+    Address src = emitPointerWithAlignment(E->getArg(0));
+    Address dest = emitPointerWithAlignment(E->getArg(1));
+    mlir::Value sizeVal = emitScalarExpr(E->getArg(2));
+    emitNonNullArgCheck(RValue::get(src.getPointer()), E->getArg(0)->getType(),
+                        E->getArg(0)->getExprLoc(), FD, 0);
+    emitNonNullArgCheck(RValue::get(dest.getPointer()), E->getArg(1)->getType(),
+                        E->getArg(1)->getExprLoc(), FD, 0);
+    builder.createMemMove(getLoc(E->getSourceRange()), dest.getPointer(),
+                          src.getPointer(), sizeVal);
+
+    return RValue::get(nullptr);
+  }
 
   case Builtin::BImemcpy:
   case Builtin::BI__builtin_memcpy:

clang/test/CIR/CodeGen/builtin-bcopy.cpp

@@ -0,0 +1,77 @@
+// RUN: %clang_cc1 -triple x86_64-unknown-linux-gnu -fclangir -emit-cir %s -o %t.cir
+// RUN: FileCheck --check-prefix=CIR --input-file=%t.cir %s
+// RUN: %clang_cc1 -triple x86_64-unknown-linux-gnu -fclangir -emit-llvm %s -o %t.ll
+// RUN: FileCheck --check-prefix=LLVM --input-file=%t.ll %s
+
+void foo(void) {
+  // CIR-LABEL: cir.func dso_local @_Z3foov()
+  // CIR: %[[V0:.*]] = cir.alloca !cir.array<!cir.float x 4>, !cir.ptr<!cir.array<!cir.float x 4>>, ["f4"] {alignment = 16 : i64}
+  // CIR: %[[V1:.*]] = cir.alloca !cir.array<!cir.float x 8>, !cir.ptr<!cir.array<!cir.float x 8>>, ["f8"] {alignment = 16 : i64}
+  // CIR: %[[V2:.*]] = cir.cast(array_to_ptrdecay, %[[V0]] : !cir.ptr<!cir.array<!cir.float x 4>>), !cir.ptr<!cir.float>
+  // CIR: %[[V3:.*]] = cir.cast(bitcast, %[[V2]] : !cir.ptr<!cir.float>), !cir.ptr<!void>
+  // CIR: %[[V4:.*]] = cir.cast(array_to_ptrdecay, %[[V1]] : !cir.ptr<!cir.array<!cir.float x 8>>), !cir.ptr<!cir.float>
+  // CIR: %[[V5:.*]] = cir.cast(bitcast, %[[V4]] : !cir.ptr<!cir.float>), !cir.ptr<!void>
+  // CIR: %[[V6:.*]] = cir.const #cir.int<4> : !u64i
+  // CIR: %[[V7:.*]] = cir.const #cir.int<4> : !s32i
+  // CIR: %[[V8:.*]] = cir.cast(integral, %[[V7]] : !s32i), !u64i
+  // CIR: %[[V9:.*]] = cir.binop(mul, %[[V6]], %[[V8]]) : !u64i
+  // CIR: cir.libc.memmove %[[V9]] bytes from %[[V3]] to %[[V5]] : !cir.ptr<!void>, !u64i
+  // CIR: cir.return
+
+  // LLVM-LABEL: define dso_local void @_Z3foov()
+  // LLVM: %[[V1:.*]] = alloca [4 x float], i64 1, align 16
+  // LLVM: %[[V2:.*]] = alloca [8 x float], i64 1, align 16
+  // LLVM: %[[V3:.*]] = getelementptr float, ptr %[[V1]], i32 0
+  // LLVM: %[[V4:.*]] = getelementptr float, ptr %[[V2]], i32 0
+  // LLVM: call void @llvm.memmove.p0.p0.i64(ptr %[[V4]], ptr %[[V3]], i64 16, i1 false)
+  // LLVM: ret void
+
+  float f4[4];
+  float f8[8];
+  __builtin_bcopy(f4, f8, sizeof(float) * 4);
+}
+
+void test_conditional_bcopy(void) {
+  // CIR-LABEL: cir.func dso_local @_Z22test_conditional_bcopyv()
+  // CIR: cir.libc.memmove {{.*}} bytes from {{.*}} to {{.*}} : !cir.ptr<!void>, !u64i
+  // CIR: cir.libc.memmove {{.*}} bytes from {{.*}} to {{.*}} : !cir.ptr<!void>, !u64i
+
+  // LLVM-LABEL: define{{.*}} void @_Z22test_conditional_bcopyv
+  // LLVM: call void @llvm.memmove
+  // LLVM: call void @llvm.memmove
+  // LLVM-NOT: phi
+
+  char dst[20];
+  char src[20];
+  int _sz = 20, len = 20;
+  return (_sz ? ((_sz >= len) ? __builtin_bcopy(src, dst, len) : foo())
+              : __builtin_bcopy(src, dst, len));
+}
+
+void another_conditional_bcopy(char *dst, char *src, int sz, int len) {
+  // CIR-LABEL: cir.func dso_local @_Z25another_conditional_bcopyPcS_ii
+  // CIR: cir.libc.memmove {{.*}} bytes from {{.*}} to {{.*}} : !cir.ptr<!void>, !u64i
+  // CIR: cir.libc.memmove {{.*}} bytes from {{.*}} to {{.*}} : !cir.ptr<!void>, !u64i
+
+  // LLVM-LABEL: define{{.*}} void @_Z25another_conditional_bcopyPcS_ii
+  // LLVM: call void @llvm.memmove
+  // LLVM: call void @llvm.memmove
+  // LLVM-NOT: phi
+
+  if (sz >= len)
+    __builtin_bcopy(src, dst, len);
+  else
+    __builtin_bcopy(src, dst, len * 2);
+}
+
+#define size_t __SIZE_TYPE__
+
+extern "C" void bcopy(const void *__src, void *__dest, size_t __n);
+
+// LLVM: @_Z9testbcopyPKvPvm(
+// LLVM:         call void @llvm.memmove.p0.p0.i64(ptr {{.*}}, ptr {{.*}}, i64 {{.*}}, i1 false)
+// LLVM:    ret void
+
+void testbcopy(const void *src, void *dest, size_t n) {
+  bcopy(src, dest, n);
+}