From c6b0d21d49a2605b2c667cec37b31140133b1fd5 Mon Sep 17 00:00:00 2001 From: Martin Liska Date: Fri, 17 Feb 2017 15:36:08 +0100 Subject: Introduce ssa_defined_default_def_p function (PR tree-optimization/79529). 2017-02-17 Martin Liska PR tree-optimization/79529 * tree-ssa-loop-unswitch.c (is_maybe_undefined): Use ssa_defined_default_def_p to handle cases which are implicitly defined. * tree-ssa.c (ssa_defined_default_def_p): New function. (ssa_undefined_value_p): Use ssa_defined_default_def_p to handle cases which are implicitly defined. * tree-ssa.h (ssa_defined_default_def_p): Declare. From-SVN: r245530 --- gcc/tree-ssa.c | 26 +++++++++++++++++++------- 1 file changed, 19 insertions(+), 7 deletions(-) (limited to 'gcc/tree-ssa.c') diff --git a/gcc/tree-ssa.c b/gcc/tree-ssa.c index 28020b0..831fd61 100644 --- a/gcc/tree-ssa.c +++ b/gcc/tree-ssa.c @@ -1251,27 +1251,39 @@ tree_ssa_strip_useless_type_conversions (tree exp) return exp; } - -/* Return true if T, an SSA_NAME, has an undefined value. PARTIAL is what - should be returned if the value is only partially undefined. */ +/* Return true if T, as SSA_NAME, has an implicit default defined value. */ bool -ssa_undefined_value_p (tree t, bool partial) +ssa_defined_default_def_p (tree t) { - gimple *def_stmt; tree var = SSA_NAME_VAR (t); if (!var) ; /* Parameters get their initial value from the function entry. */ else if (TREE_CODE (var) == PARM_DECL) - return false; + return true; /* When returning by reference the return address is actually a hidden parameter. */ else if (TREE_CODE (var) == RESULT_DECL && DECL_BY_REFERENCE (var)) - return false; + return true; /* Hard register variables get their initial value from the ether. */ else if (VAR_P (var) && DECL_HARD_REGISTER (var)) + return true; + + return false; +} + + +/* Return true if T, an SSA_NAME, has an undefined value. PARTIAL is what + should be returned if the value is only partially undefined. */ + +bool +ssa_undefined_value_p (tree t, bool partial) +{ + gimple *def_stmt; + + if (ssa_defined_default_def_p (t)) return false; /* The value is undefined iff its definition statement is empty. */ -- cgit v1.1