diff --git a/gcc/ChangeLog b/gcc/ChangeLog index 58b8baddd89cddde27c78ba256c4109532a7b3ed..4f8f3a61f016cf06d6fbf7d11325d81ea3ac9923 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,9 @@ +2004-12-23 Mark Mitchell <mark@codesourcery.com> + + PR c++/16405 + * gimplify.c (gimplify_modify_expr_rhs): Handle + INDIRECT_REF/ADDR_EXPR combinations. + 2004-12-22 Richard Henderson <rth@redhat.com> * config/alpha/alpha.c (alpha_expand_mov): Split out ... diff --git a/gcc/gimplify.c b/gcc/gimplify.c index 2434a815c7c355e7252c3212aa9f09bbd438870c..0f610e4d24242542f575533737a3ff66084665dc 100644 --- a/gcc/gimplify.c +++ b/gcc/gimplify.c @@ -2801,6 +2801,33 @@ gimplify_modify_expr_rhs (tree *expr_p, tree *from_p, tree *to_p, tree *pre_p, while (ret != GS_UNHANDLED) switch (TREE_CODE (*from_p)) { + case INDIRECT_REF: + { + /* If we have code like + + *(const A*)(A*)&x + + where the type of "x" is a (possibly cv-qualified variant + of "A"), treat the entire expression as identical to "x". + This kind of code arises in C++ when an object is bound + to a const reference, and if "x" is a TARGET_EXPR we want + to take advantage of the optimization below. */ + tree pointer; + + pointer = TREE_OPERAND (*from_p, 0); + STRIP_NOPS (pointer); + if (TREE_CODE (pointer) == ADDR_EXPR + && (TYPE_MAIN_VARIANT (TREE_TYPE (TREE_OPERAND (pointer, 0))) + == TYPE_MAIN_VARIANT (TREE_TYPE (*from_p)))) + { + *from_p = TREE_OPERAND (pointer, 0); + ret = GS_OK; + } + else + ret = GS_UNHANDLED; + break; + } + case TARGET_EXPR: { /* If we are initializing something from a TARGET_EXPR, strip the diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog index b966939c2ac1498ed68cb9ccc8b8f0b16bf95221..61347db2c40cd07173b3a0d7e5e695b1a47e5e01 100644 --- a/gcc/testsuite/ChangeLog +++ b/gcc/testsuite/ChangeLog @@ -1,3 +1,8 @@ +2004-12-23 Mark Mitchell <mark@codesourcery.com> + + PR c++/16405 + * g++.dg/opt/temp1.C: New test. + 2004-12-23 Giovanni Bajo <giovannibajo@gcc.gnu.org> PR c++/18733 diff --git a/gcc/testsuite/g++.dg/opt/temp1.C b/gcc/testsuite/g++.dg/opt/temp1.C new file mode 100644 index 0000000000000000000000000000000000000000..f34bb8fff582acaa147bf2926f0065f948684b0b --- /dev/null +++ b/gcc/testsuite/g++.dg/opt/temp1.C @@ -0,0 +1,39 @@ +// PR c++/16405 +// { dg-options "-O2" } + +// There should be exactly one temporary generated for the code in "f" +// below when optimizing -- for the result of "b + c". We have no +// easy way of checking that directly, so we count the number of calls +// to "memcpy", which is used on (some?) targets to copy temporaries. +// If there is more than two calls (one for coping "*this" to "t", and +// one for copying the temporary to "a"), then there are too many +// temporaries. + +int i; + +extern "C" +void *memcpy (void *dest, const void *src, __SIZE_TYPE__ n) +{ + ++i; +} + +struct T { + int a[128]; + T &operator+=(T const &v) __attribute__((noinline)); + T operator+(T const &v) const { T t = *this; t += v; return t; } +}; + +T &T::operator+=(T const &v) { + return *this; +} + +T a, b, c; + +void f() { a = b + c; } + +int main () { + i = 0; + f(); + if (i > 2) + return 1; +}