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| author | Roger Sayle <roger@eyesopen.com> | 2003-04-20 03:11:14 +0000 |
|---|---|---|
| committer | Roger Sayle <sayle@gcc.gnu.org> | 2003-04-20 03:11:14 +0000 |
| commit | 0a45ec5c78e634e129fe3e9bbcddf6b721a10ca8 (patch) | |
| tree | d3c6dc4d970337ee030f7fda0105a2d638d5ef0e /gcc | |
| parent | 4049c77a01ab09b2b8bf59bd71a873ba672bcf86 (diff) | |
| download | gcc-0a45ec5c78e634e129fe3e9bbcddf6b721a10ca8.zip gcc-0a45ec5c78e634e129fe3e9bbcddf6b721a10ca8.tar.gz gcc-0a45ec5c78e634e129fe3e9bbcddf6b721a10ca8.tar.bz2 | |
builtins.c (expand_builtin): Don't expand a pure or const built-in function if...
* builtins.c (expand_builtin): Don't expand a pure or const
built-in function if the result will be ignored and none of
its arguments are volatile.
From-SVN: r65843
Diffstat (limited to 'gcc')
| -rw-r--r-- | gcc/ChangeLog | 6 | ||||
| -rw-r--r-- | gcc/builtins.c | 30 |
2 files changed, 36 insertions, 0 deletions
diff --git a/gcc/ChangeLog b/gcc/ChangeLog index c73e181..8d73923 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,9 @@ +2003-04-19 Roger Sayle <roger@eyesopen.com> + + * builtins.c (expand_builtin): Don't expand a pure or const + built-in function if the result will be ignored and none of + its arguments are volatile. + 2003-04-19 Kean Johnston <jkj@sco.com> * unwind-dw2.c (_Unwind_GetCFA): cast return to avoid warning diff --git a/gcc/builtins.c b/gcc/builtins.c index 89f9531..87437d0 100644 --- a/gcc/builtins.c +++ b/gcc/builtins.c @@ -4139,6 +4139,36 @@ expand_builtin (exp, target, subtarget, mode, ignore) break; } + /* The built-in function expanders test for target == const0_rtx + to determine whether the function's result will be ignored. */ + if (ignore) + target = const0_rtx; + + /* If the result of a pure or const built-in function is ignored, and + none of its arguments are volatile, we can avoid expanding the + built-in call and just evaluate the arguments for side-effects. */ + if (target == const0_rtx + && (DECL_IS_PURE (fndecl) || TREE_READONLY (fndecl))) + { + bool volatilep = false; + tree arg; + + for (arg = arglist; arg; arg = TREE_CHAIN (arg)) + if (TREE_THIS_VOLATILE (TREE_VALUE (arg))) + { + volatilep = true; + break; + } + + if (! volatilep) + { + for (arg = arglist; arg; arg = TREE_CHAIN (arg)) + expand_expr (TREE_VALUE (arg), const0_rtx, + VOIDmode, EXPAND_NORMAL); + return const0_rtx; + } + } + switch (fcode) { case BUILT_IN_ABS: |