diff options
Diffstat (limited to 'gcc/gimplify.c')
| -rw-r--r-- | gcc/gimplify.c | 12 |
1 files changed, 10 insertions, 2 deletions
diff --git a/gcc/gimplify.c b/gcc/gimplify.c index 54d5c46..a58738e 100644 --- a/gcc/gimplify.c +++ b/gcc/gimplify.c @@ -3728,7 +3728,15 @@ tree_to_gimple_tuple (tree *tp) /* Promote partial stores to COMPLEX variables to total stores. *EXPR_P is a MODIFY_EXPR with a lhs of a REAL/IMAGPART_EXPR of a variable with - DECL_GIMPLE_REG_P set. */ + DECL_GIMPLE_REG_P set. + + IMPORTANT NOTE: This promotion is performed by introducing a load of the + other, unmodified part of the complex object just before the total store. + As a consequence, if the object is still uninitialized, an undefined value + will be loaded into a register, which may result in a spurious exception + if the register is floating-point and the value happens to be a signaling + NaN for example. Then the fully-fledged complex operations lowering pass + followed by a DCE pass are necessary in order to fix things up. */ static enum gimplify_status gimplify_modify_expr_complex_part (tree *expr_p, tree *pre_p, bool want_value) @@ -6462,7 +6470,7 @@ gimplify_function_tree (tree fndecl) ret = DECL_RESULT (fndecl); if ((TREE_CODE (TREE_TYPE (ret)) == COMPLEX_TYPE - || TREE_CODE (TREE_TYPE (ret)) == VECTOR_TYPE) + || TREE_CODE (TREE_TYPE (ret)) == VECTOR_TYPE) && !needs_to_live_in_memory (ret)) DECL_GIMPLE_REG_P (ret) = 1; |