On Fri, Nov 29, 2024 at 3:04 AM Joseph Myers <josmy...@redhat.com> wrote:
>
> As reported in bug 100501 (plus duplicates), the gimplifier ICEs for C
> tests involving a statement expression not returning a value as an asm
> input.
>
> The expected diagnostic for this case (as seen for C++ input) is one
> coming from the gimplifier and so it seems reasonable to fix the
> gimplifier to handle the GENERIC generated for this case by the C
> front end, rather than trying to make the C front end detect it
> earlier. Thus, adjust two places in the gimplifier to work with
> gimplifying a BIND_EXPR changing *expr_p to NULL_TREE.
>
> Bootstrapped with no regressions for x86_64-pc-linux-gnu. OK to commit?
>
> PR c/100501
>
> gcc/
> * gimplify.cc (gimplify_expr): Do not call gimple_test_f on
> *expr_p when it has become null.
> (gimplify_asm_expr): Handle TREE_VALUE (link) becoming null.
>
> gcc/testsuite/
> * gcc.dg/pr100501-1.c: New test.
>
> diff --git a/gcc/gimplify.cc b/gcc/gimplify.cc
> index fb0ca23bfb6c..090f8987d5d3 100644
> --- a/gcc/gimplify.cc
> +++ b/gcc/gimplify.cc
> @@ -7457,6 +7457,13 @@ gimplify_asm_expr (tree *expr_p, gimple_seq *pre_p,
> gimple_seq *post_p)
> TREE_VALUE (link) = error_mark_node;
> tret = gimplify_expr (&TREE_VALUE (link), pre_p, post_p,
> is_gimple_lvalue, fb_lvalue | fb_mayfail);
> + if (TREE_VALUE (link) == NULL_TREE)
I think we're trying to handle errorneous cases by setting TREE_VALUE
to error_mark_node
before this, so how about the following instead?
diff --git a/gcc/gimplify.cc b/gcc/gimplify.cc
index fb0ca23bfb6..aa99c0a98f7 100644
--- a/gcc/gimplify.cc
+++ b/gcc/gimplify.cc
@@ -7453,7 +7453,8 @@ gimplify_asm_expr (tree *expr_p, gimple_seq
*pre_p, gimple_seq *post_p)
|| TREE_CODE (inputv) == PREINCREMENT_EXPR
|| TREE_CODE (inputv) == POSTDECREMENT_EXPR
|| TREE_CODE (inputv) == POSTINCREMENT_EXPR
- || TREE_CODE (inputv) == MODIFY_EXPR)
+ || TREE_CODE (inputv) == MODIFY_EXPR
+ || VOID_TYPE_P (TREE_TYPE (inputv)))
TREE_VALUE (link) = error_mark_node;
tret = gimplify_expr (&TREE_VALUE (link), pre_p, post_p,
is_gimple_lvalue, fb_lvalue | fb_mayfail);
> + {
> + /* This can occur when an asm input is a BIND_EXPR for a
> + statement expression not returning a value. */
> + tret = GS_ERROR;
> + TREE_VALUE (link) = error_mark_node;
> + }
> if (tret != GS_ERROR)
> {
> /* Unlike output operands, memory inputs are not guaranteed
> @@ -19662,10 +19669,11 @@ gimplify_expr (tree *expr_p, gimple_seq *pre_p,
> gimple_seq *post_p,
>
> /* Otherwise we're gimplifying a subexpression, so the resulting
> value is interesting. If it's a valid operand that matches
> - GIMPLE_TEST_F, we're done. Unless we are handling some
> - post-effects internally; if that's the case, we need to copy into
> - a temporary before adding the post-effects to POST_P. */
> - if (gimple_seq_empty_p (internal_post) && (*gimple_test_f) (*expr_p))
> + GIMPLE_TEST_F, or it's now NULL_TREE, we're done. Unless we are
> + handling some post-effects internally; if that's the case, we need
> + to copy into a temporary before adding the post-effects to POST_P. */
> + if (gimple_seq_empty_p (internal_post)
> + && (!*expr_p || (*gimple_test_f) (*expr_p)))
> goto out;
>
> /* Otherwise, we need to create a new temporary for the gimplified
> diff --git a/gcc/testsuite/gcc.dg/pr100501-1.c
> b/gcc/testsuite/gcc.dg/pr100501-1.c
> new file mode 100644
> index 000000000000..b5b3781a9c2f
> --- /dev/null
> +++ b/gcc/testsuite/gcc.dg/pr100501-1.c
> @@ -0,0 +1,26 @@
> +/* Test ICE for statement expression returning no value as asm input (bug
> + 100501). */
> +/* { dg-do compile } */
> +/* { dg-options "" } */
> +
> +int x;
> +int g ();
> +
> +void
> +f ()
> +{
> + __asm__ ("" : : "m" (({}))); /* { dg-error "memory input 0 is not directly
> addressable" } */
> + __asm__ ("" : : "m" (({ ; }))); /* { dg-error "memory input 0 is not
> directly addressable" } */
> + __asm__ ("" : : "m" (({ (void) 0; }))); /* { dg-error "memory input 0 is
> not directly addressable" } */
> + __asm__ ("" : : "m" (({ f (); }))); /* { dg-error "memory input 0 is not
> directly addressable|using result of function returning 'void'" } */
> + __asm__ ("" : : "m" (({ f (); f (); }))); /* { dg-error "memory input 0 is
> not directly addressable" } */
> + __asm__ ("" : : "m" (({ x = g (); f (); }))); /* { dg-error "memory input
> 0 is not directly addressable" } */
> + __asm__ ("" : : "m" (({ if (1) g (); }))); /* { dg-error "memory input 0
> is not directly addressable" } */
> + __asm__ ("" : : "m" (({ if (1) g (); else g (); }))); /* { dg-error
> "memory input 0 is not directly addressable" } */
> + __asm__ ("" : : "m" (({ test : goto test; }))); /* { dg-error "memory
> input 0 is not directly addressable" } */
> + __asm__ ("" : : "m" (({ return; }))); /* { dg-error "memory input 0 is not
> directly addressable" } */
> + __asm__ ("" : : "m" (({ while (1); }))); /* { dg-error "memory input 0 is
> not directly addressable" } */
> + __asm__ ("" : : "m" (({ do {} while (1); }))); /* { dg-error "memory input
> 0 is not directly addressable" } */
> + __asm__ ("" : : "m" (({ for (;;); }))); /* { dg-error "memory input 0 is
> not directly addressable" } */
> + __asm__ ("" : : "m" (({ switch (x); }))); /* { dg-error "memory input 0 is
> not directly addressable" } */
> +}
>
> --
> Joseph S. Myers
> josmy...@redhat.com
>
