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| author | Jan Pokorný <pokorny_jan@seznam.cz> | 2012-05-10 03:07:47 -0700 |
|---|---|---|
| committer | Christopher Li <sparse@chrisli.org> | 2012-05-10 03:07:47 -0700 |
| commit | 955cd225d2e3ee708e20de825eca82c8797897fd (patch) | |
| tree | 810055d62f0206440dc2132b69d109ae0186efb4 | |
| parent | 695dd9d068dd2316b92706d174df9e30c1e71dcf (diff) | |
| download | sparse-dev-955cd225d2e3ee708e20de825eca82c8797897fd.tar.gz | |
simplify: conservative handling of casts with pointers
On 05/08/2012 04:13 PM, Jan Pokorný wrote:
> When the cast is optimized out/target pointer type information lost,
> it may be impossible for backend to recover it (think of
> "struct foo *my_new_foo = malloc(sizeof(*my_new_foo))").
>
> Losing such pointer type information can be wider issue (structs and
> unions maybe), but this is the most exposed one and the patch tries
> to be minimal in this regard and the impact seems to be minimal
> too as usually type-correctness is followed.
I expected that if both operands of the cast appear to be pointers, it is
always OP_PTRCAST case, which is not true.
So this version exchanges inequality test for "or". Beside being
shorter, it covers such previously missed cases.
Based on asserts I experimented with, OP_PTRCASTs are always captured
by the condition implicitly (beside OP_CASTs with pointer-like operands).
Signed-off-by: Jan Pokorný <pokorny_jan@seznam.cz>
Signed-off-by: Christopher Li <sparse@chrisli.org>
| -rw-r--r-- | simplify.c | 6 |
1 files changed, 6 insertions, 0 deletions
@@ -10,6 +10,7 @@ #include "expression.h" #include "linearize.h" #include "flow.h" +#include "symbol.h" /* Find the trivial parent for a phi-source */ static struct basic_block *phi_parent(struct basic_block *source, pseudo_t pseudo) @@ -667,6 +668,11 @@ static int simplify_cast(struct instruction *insn) orig_type = insn->orig_type; if (!orig_type) return 0; + + /* Keep casts with pointer on either side (not only case of OP_PTRCAST) */ + if (is_ptr_type(orig_type) || is_ptr_type(insn->type)) + return 0; + orig_size = orig_type->bit_size; size = insn->size; src = insn->src; |