On November 21, 2014 9:07:50 PM CET, Martin Jambor <mjam...@suse.cz> wrote:
>Hi,
>
>the testcase of PR 63551 passes a union between a signed and an
>unsigned integer between two functions as a parameter. The caller
>initializes to an unsigned integer with the highest order bit set, the
>callee loads the data through the signed field and compares with zero.
>evaluate_conditions_for_known_args then wrongly evaluated the
>condition in these circumstances, which later on lead to insertion of
>builtin_unreachable and miscompilation.
>
>Fixed by fold_converting the known value first. I use the type of the
>value in the condition which should do exactly the right thing because
>the value is taken from the corresponding gimple_cond statement in
>which types must match.
>
>Bootstrapped and tested on x86_64-linux. OK for trunk?
I think you want to use fold_unary (VIEW_CONVERT,...) Here if you consider the
case with
Int and float. And "fail" if that returns NULL or not a constant.
Thanks,
Richard.
>Thanks,
>
>Martin
>
>
>2014-11-21 Martin Jambor <mjam...@suse.cz>
>
> PR ipa/63551
> * ipa-inline-analysis.c (evaluate_conditions_for_known_args): Convert
> value of the argument to the type of the value in the condition.
>
>testsuite/
> * gcc.dg/ipa/pr63551.c: New test.
>
>
>Index: src/gcc/ipa-inline-analysis.c
>===================================================================
>--- src.orig/gcc/ipa-inline-analysis.c
>+++ src/gcc/ipa-inline-analysis.c
>@@ -880,6 +880,7 @@ evaluate_conditions_for_known_args (stru
> }
> if (c->code == IS_NOT_CONSTANT || c->code == CHANGED)
> continue;
>+ val = fold_convert (TREE_TYPE (c->val), val);
>res = fold_binary_to_constant (c->code, boolean_type_node, val,
>c->val);
> if (res && integer_zerop (res))
> continue;
>Index: src/gcc/testsuite/gcc.dg/ipa/pr63551.c
>===================================================================
>--- /dev/null
>+++ src/gcc/testsuite/gcc.dg/ipa/pr63551.c
>@@ -0,0 +1,33 @@
>+/* { dg-do run } */
>+/* { dg-options "-Os" } */
>+
>+union U
>+{
>+ unsigned int f0;
>+ int f1;
>+};
>+
>+int a, d;
>+
>+void
>+fn1 (union U p)
>+{
>+ if (p.f1 <= 0)
>+ if (a)
>+ d = 0;
>+}
>+
>+void
>+fn2 ()
>+{
>+ d = 0;
>+ union U b = { 4294967286 };
>+ fn1 (b);
>+}
>+
>+int
>+main ()
>+{
>+ fn2 ();
>+ return 0;
>+}
