diff options
Diffstat (limited to 'gcc/tree-ssa-alias.c')
| -rw-r--r-- | gcc/tree-ssa-alias.c | 39 |
1 files changed, 20 insertions, 19 deletions
diff --git a/gcc/tree-ssa-alias.c b/gcc/tree-ssa-alias.c index 94ccd80..7ad1867 100644 --- a/gcc/tree-ssa-alias.c +++ b/gcc/tree-ssa-alias.c @@ -1492,33 +1492,34 @@ maybe_create_global_var (struct alias_info *ai) size_t i, n_clobbered; /* No need to create it, if we have one already. */ - if (global_var) - return; - - /* Count all the call-clobbered variables. */ - n_clobbered = 0; - EXECUTE_IF_SET_IN_BITMAP (call_clobbered_vars, 0, i, n_clobbered++); + if (global_var == NULL_TREE) + { + /* Count all the call-clobbered variables. */ + n_clobbered = 0; + EXECUTE_IF_SET_IN_BITMAP (call_clobbered_vars, 0, i, n_clobbered++); - /* Create .GLOBAL_VAR if we have too many call-clobbered variables. - We also create .GLOBAL_VAR when there no call-clobbered variables - to prevent code motion transformations from re-arranging function - calls that may have side effects. For instance, + /* Create .GLOBAL_VAR if we have too many call-clobbered + variables. We also create .GLOBAL_VAR when there no + call-clobbered variables to prevent code motion + transformations from re-arranging function calls that may + have side effects. For instance, - foo () + foo () { int a = f (); g (); h (a); } - There are no call-clobbered variables in foo(), so it would be - entirely possible for a pass to want to move the call to f() - after the call to g(). If f() has side effects, that would be - wrong. Creating .GLOBAL_VAR in this case will insert VDEFs for - it and prevent such transformations. */ - if (n_clobbered == 0 - || ai->num_calls_found * n_clobbered >= (size_t) GLOBAL_VAR_THRESHOLD) - create_global_var (); + There are no call-clobbered variables in foo(), so it would + be entirely possible for a pass to want to move the call to + f() after the call to g(). If f() has side effects, that + would be wrong. Creating .GLOBAL_VAR in this case will + insert VDEFs for it and prevent such transformations. */ + if (n_clobbered == 0 + || ai->num_calls_found * n_clobbered >= (size_t) GLOBAL_VAR_THRESHOLD) + create_global_var (); + } /* If the function has calls to clobbering functions and .GLOBAL_VAR has been created, make it an alias for all call-clobbered variables. */ |