| Eric Christopher | 5dcca66 | 2011-07-27 23:46:26 +0000 | [diff] [blame^] | 1 | // RUN: %clang_cc1 -emit-llvm -o - %s | not grep readonly |
| 2 | // RUN: %clang_cc1 -emit-llvm -o - %s | not grep readnone |
| Eric Christopher | 3883e66 | 2011-07-26 22:17:02 +0000 | [diff] [blame] | 3 | |
| 4 | // The struct being passed byval means that we cannot mark the |
| 5 | // function readnone. Readnone would allow stores to the arg to |
| 6 | // be deleted in the caller. We also don't allow readonly since |
| 7 | // the callee might write to the byval parameter. The inliner |
| 8 | // would have to assume the worse and introduce an explicit |
| 9 | // temporary when inlining such a function, which is costly for |
| 10 | // the common case in which the byval argument is not written. |
| 11 | struct S { int A[1000]; }; |
| 12 | int __attribute__ ((const)) f(struct S x) { x.A[1] = 0; return x.A[0]; } |
| 13 | int g(struct S x) __attribute__ ((pure)); |
| 14 | int h(struct S x) { return g(x); } |