c++: Mark __builtin_convertvector operand as read [PR93557]

In C++ we weren't calling mark_exp_read on the __builtin_convertvector first
argument.  I guess it could misbehave even with lambda implicit captures.

Fixed by calling decay_conversion on the argument, we use the argument as
rvalue so we want the standard lvalue to rvalue conversions, but as the
argument must be a vector type, e.g. integral promotions aren't really
needed.

2020-02-05  Jakub Jelinek  <jakub@redhat.com>

	PR c++/93557
	* semantics.c (cp_build_vec_convert): Call decay_conversion on arg
	prior to passing it to c_build_vec_convert.

	* c-c++-common/Wunused-var-17.c: New test.
This commit is contained in:
Jakub Jelinek 2020-02-05 23:35:08 +01:00
parent d10cddeaad
commit 5a8ad97b6e
4 changed files with 32 additions and 1 deletions

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@ -1,3 +1,9 @@
2020-02-05 Jakub Jelinek <jakub@redhat.com>
PR c++/93557
* semantics.c (cp_build_vec_convert): Call decay_conversion on arg
prior to passing it to c_build_vec_convert.
2020-02-05 Michael Meissner <meissner@linux.ibm.com>
PR target/93568

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@ -10389,7 +10389,8 @@ cp_build_vec_convert (tree arg, location_t loc, tree type,
tree ret = NULL_TREE;
if (!type_dependent_expression_p (arg) && !dependent_type_p (type))
ret = c_build_vec_convert (cp_expr_loc_or_input_loc (arg), arg,
ret = c_build_vec_convert (cp_expr_loc_or_input_loc (arg),
decay_conversion (arg, complain),
loc, type, (complain & tf_error) != 0);
if (!processing_template_decl)

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@ -1,3 +1,8 @@
2020-02-05 Jakub Jelinek <jakub@redhat.com>
PR c++/93557
* c-c++-common/Wunused-var-17.c: New test.
2020-02-05 Jeff Law <law@redhat.com>
* gcc.target/hppa/shadd-3.c: Disable delay slot filling and

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@ -0,0 +1,19 @@
/* PR c++/93557 */
/* { dg-do compile } */
/* { dg-options "-O2 -Wunused-but-set-variable" } */
typedef int VI __attribute__((vector_size (sizeof (int) * 4)));
typedef float VF __attribute__((vector_size (sizeof (float) * 4)));
void
foo (VI *p, VF *q)
{
VI a = (VI) { 1, 2, 3, 4 }; /* { dg-bogus "set but not used" } */
q[0] = __builtin_convertvector (a, VF);
VI b = p[1]; /* { dg-bogus "set but not used" } */
q[1] = __builtin_convertvector (b, VF);
VF c = (VF) { 5.0f, 6.0f, 7.0f, 8.0f }; /* { dg-bogus "set but not used" } */
p[2] = __builtin_convertvector (c, VI);
VF d = q[3]; /* { dg-bogus "set but not used" } */
p[3] = __builtin_convertvector (d, VI);
}