From 1a8c909ebd0bbd58ed5308bc66dc923ec5cfaafd Mon Sep 17 00:00:00 2001 From: Eric Botcazou Date: Wed, 17 Sep 2008 21:48:08 +0000 Subject: [PATCH] varasm.c (initializer_constant_valid_p): Forbid view-conversions from aggregate to non-aggregate type if... * varasm.c (initializer_constant_valid_p): Forbid view-conversions from aggregate to non-aggregate type if the bit pattern is not fully preserved afterwards. From-SVN: r140432 --- gcc/ChangeLog | 6 ++++ gcc/testsuite/ChangeLog | 4 +++ .../gnat.dg/specs/static_initializer3.ads | 27 ++++++++++++++++++ gcc/varasm.c | 33 ++++++++++++++++------ 4 files changed, 62 insertions(+), 8 deletions(-) create mode 100644 gcc/testsuite/gnat.dg/specs/static_initializer3.ads diff --git a/gcc/ChangeLog b/gcc/ChangeLog index fc5263e..48b5f0e 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,9 @@ +2008-09-17 Eric Botcazou + + * varasm.c (initializer_constant_valid_p): Forbid view-conversions + from aggregate to non-aggregate type if the bit pattern is not fully + preserved afterwards. + 2008-09-17 Richard Guenther * tree-cfg.c (verify_types_in_gimple_assign): Rename to ... diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog index 9933c79..ed9d1e3 100644 --- a/gcc/testsuite/ChangeLog +++ b/gcc/testsuite/ChangeLog @@ -1,3 +1,7 @@ +2008-09-17 Eric Botcazou + + * gnat.dg/specs/static_initializer3.ads: New test. + 2008-09-17 Jakub Jelinek PR c++/37552 diff --git a/gcc/testsuite/gnat.dg/specs/static_initializer3.ads b/gcc/testsuite/gnat.dg/specs/static_initializer3.ads new file mode 100644 index 0000000..42994f2 --- /dev/null +++ b/gcc/testsuite/gnat.dg/specs/static_initializer3.ads @@ -0,0 +1,27 @@ +with Unchecked_Conversion; + +package Static_Initializer3 is + + type Byte is range 0 .. 16#FF#; + for Byte'Size use 8; + + type Word is range 0 .. 16#FFFF# ; + for Word'Size use 16; + + type R is record + b1 : Boolean; + b2 : Boolean; + end record; + for R use record + b1 at 0 range 0..3; + b2 at 0 range 4..7; + end record; + for R'Size use 8; + + function Conv is new Unchecked_Conversion (R, Byte); + + C1 : constant Byte := Conv ((true, false)); + + C2 : constant Word := Word(C1); + +end Static_Initializer3; diff --git a/gcc/varasm.c b/gcc/varasm.c index 5728d19..e74adae 100644 --- a/gcc/varasm.c +++ b/gcc/varasm.c @@ -4205,19 +4205,36 @@ initializer_constant_valid_p (tree value, tree endtype) return op0; } - case VIEW_CONVERT_EXPR: case NON_LVALUE_EXPR: return initializer_constant_valid_p (TREE_OPERAND (value, 0), endtype); - CASE_CONVERT: + case VIEW_CONVERT_EXPR: { - tree src; - tree src_type; - tree dest_type; + tree src = TREE_OPERAND (value, 0); + tree src_type = TREE_TYPE (src); + tree dest_type = TREE_TYPE (value); + + /* Allow view-conversions from aggregate to non-aggregate type only + if the bit pattern is fully preserved afterwards; otherwise, the + RTL expander won't be able to apply a subsequent transformation + to the underlying constructor. */ + if (AGGREGATE_TYPE_P (src_type) && !AGGREGATE_TYPE_P (dest_type)) + { + if (TYPE_MODE (endtype) == TYPE_MODE (dest_type)) + return initializer_constant_valid_p (src, endtype); + else + return NULL_TREE; + } + + /* Allow all other kinds of view-conversion. */ + return initializer_constant_valid_p (src, endtype); + } - src = TREE_OPERAND (value, 0); - src_type = TREE_TYPE (src); - dest_type = TREE_TYPE (value); + CASE_CONVERT: + { + tree src = TREE_OPERAND (value, 0); + tree src_type = TREE_TYPE (src); + tree dest_type = TREE_TYPE (value); /* Allow conversions between pointer types, floating-point types, and offset types. */ -- 2.7.4