llvm/test/CFrontend/2008-01-25-ByValReadNone.c
Duncan Sands 07d403e222 Pure/const functions with ByVal parameters cannot
be marked readonly either.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@46456 91177308-0d34-0410-b5e6-96231b3b80d8
2008-01-28 19:25:47 +00:00

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C

// RUN: %llvmgcc -O3 -S -o - -emit-llvm %s | not grep readonly
// RUN: %llvmgcc -O3 -S -o - -emit-llvm %s | not grep 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) { return x.A[0]; }
int g(struct S x) __attribute__ ((pure));
int h(struct S x) { return g(x); }