File: 2008-01-25-ByValReadNone.c

package info (click to toggle)
llvm-toolchain-20 1%3A20.1.8-1~exp1
  • links: PTS, VCS
  • area: main
  • in suites: experimental
  • size: 2,111,388 kB
  • sloc: cpp: 7,438,767; ansic: 1,393,871; asm: 1,012,926; python: 241,728; f90: 86,635; objc: 75,411; lisp: 42,144; pascal: 17,286; sh: 10,027; ml: 5,082; perl: 4,730; awk: 3,523; makefile: 3,349; javascript: 2,251; xml: 892; fortran: 672
file content (17 lines) | stat: -rw-r--r-- 823 bytes parent folder | download | duplicates (39) 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
 
// RUN: %clang_cc1 -triple x86_64-unknown-unknown -emit-llvm -o - %s | FileCheck %s

// It could hit in @llvm.memcpy with "-triple x86_64-(mingw32|win32)".
// CHECK-NOT: readonly
// CHECK-NOT: readnone

// The struct being passed byval means that we cannot mark the
// function readnone.  Readnone would allow stores to the arg to
// be deleted in the caller.  We also don't allow readonly since
// the callee might write to the byval parameter.  The inliner
// would have to assume the worse and introduce an explicit
// temporary when inlining such a function, which is costly for
// the common case in which the byval argument is not written.
struct S { int A[1000]; };
int __attribute__ ((const)) f(struct S x) { x.A[1] = 0; return x.A[0]; }
int g(struct S x) __attribute__ ((pure));
int h(struct S x) { return g(x); }