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| author | Roger Sayle <sayle@gcc.gnu.org> | 2003-06-04 12:07:52 +0000 |
|---|---|---|
| committer | Roger Sayle <sayle@gcc.gnu.org> | 2003-06-04 12:07:52 +0000 |
| commit | 8c6a82695b85f8ed74cdc67f2cf74c5a62d0d91d (patch) | |
| tree | 3db65d6f6c47477a6b251f457addfa72eb727e45 /gcc/calls.c | |
| parent | e2d8bb2946c433461b613996567250b72b87cd24 (diff) | |
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calls.c (expand_call): Avoid calling pure or const functions when the result is ignored (or void) and...
* calls.c (expand_call): Avoid calling pure or const functions
when the result is ignored (or void) and none of the arguments
are volatile. Move warning diagnostic earlier in function.
From-SVN: r67436
Diffstat (limited to 'gcc/calls.c')
| -rw-r--r-- | gcc/calls.c | 36 |
1 files changed, 31 insertions, 5 deletions
diff --git a/gcc/calls.c b/gcc/calls.c index 4e95735..db6b884 100644 --- a/gcc/calls.c +++ b/gcc/calls.c @@ -2211,6 +2211,37 @@ expand_call (exp, target, ignore) else flags |= flags_from_decl_or_type (TREE_TYPE (TREE_TYPE (p))); + /* Warn if this value is an aggregate type, + regardless of which calling convention we are using for it. */ + if (warn_aggregate_return && AGGREGATE_TYPE_P (TREE_TYPE (exp))) + warning ("function call has aggregate value"); + + /* If the result of a pure or const function call is ignored (or void), + and none of its arguments are volatile, we can avoid expanding the + call and just evaluate the arguments for side-effects. */ + if ((flags & (ECF_CONST | ECF_PURE)) + && (ignore || target == const0_rtx + || TYPE_MODE (TREE_TYPE (exp)) == VOIDmode)) + { + bool volatilep = false; + tree arg; + + for (arg = actparms; arg; arg = TREE_CHAIN (arg)) + if (TREE_THIS_VOLATILE (TREE_VALUE (arg))) + { + volatilep = true; + break; + } + + if (! volatilep) + { + for (arg = actparms; arg; arg = TREE_CHAIN (arg)) + expand_expr (TREE_VALUE (arg), const0_rtx, + VOIDmode, EXPAND_NORMAL); + return const0_rtx; + } + } + #ifdef REG_PARM_STACK_SPACE #ifdef MAYBE_REG_PARM_STACK_SPACE reg_parm_stack_space = MAYBE_REG_PARM_STACK_SPACE; @@ -2224,11 +2255,6 @@ expand_call (exp, target, ignore) must_preallocate = 1; #endif - /* Warn if this value is an aggregate type, - regardless of which calling convention we are using for it. */ - if (warn_aggregate_return && AGGREGATE_TYPE_P (TREE_TYPE (exp))) - warning ("function call has aggregate value"); - /* Set up a place to return a structure. */ /* Cater to broken compilers. */ |