[gcc r12-4031] middle-end/102518 - avoid invalid GIMPLE during inlining

[Richard Biener <rguenth@gcc.gnu.org>]

https://gcc.gnu.org/g:3a7f20ed26416b56df6f3c8240f3c65a5715b17d

commit r12-4031-g3a7f20ed26416b56df6f3c8240f3c65a5715b17d
Author: Richard Biener <rguenther@suse.de>
Date:   Thu Sep 30 15:05:53 2021 +0200

    middle-end/102518 - avoid invalid GIMPLE during inlining
    
    When inlining we have to avoid mapping a non-lvalue parameter
    value into a context that prevents the parameter to be a register.
    Formerly the register were TREE_ADDRESSABLE but now it can be
    just DECL_NOT_GIMPLE_REG_P.
    
    2021-09-30  Richard Biener  <rguenther@suse.de>
    
            PR middle-end/102518
            * tree-inline.c (setup_one_parameter): Avoid substituting
            an invariant into contexts where a GIMPLE register is not valid.
    
            * gcc.dg/torture/pr102518.c: New testcase.

Diff:
---
 gcc/testsuite/gcc.dg/torture/pr102518.c | 12 ++++++++++++
 gcc/tree-inline.c                       |  6 +++++-
 2 files changed, 17 insertions(+), 1 deletion(-)

diff --git a/gcc/testsuite/gcc.dg/torture/pr102518.c b/gcc/testsuite/gcc.dg/torture/pr102518.c
new file mode 100644
index 00000000000..bd181ec9d99
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/torture/pr102518.c
@@ -0,0 +1,12 @@
+/* { dg-do compile } */
+
+struct A {
+  int *x;
+};
+int i;
+int f(int *const c) {
+  struct A * b = (struct A *)(&c);
+  return b->x != 0;
+}
+void g() { f(&i); }
+
diff --git a/gcc/tree-inline.c b/gcc/tree-inline.c
index 5e50e8013e2..e292a144967 100644
--- a/gcc/tree-inline.c
+++ b/gcc/tree-inline.c
@@ -3490,7 +3490,11 @@ setup_one_parameter (copy_body_data *id, tree p, tree value, tree fn,
       /* We may produce non-gimple trees by adding NOPs or introduce invalid
 	 sharing when the value is not constant or DECL.  And we need to make
 	 sure that it cannot be modified from another path in the callee.  */
-      if ((is_gimple_min_invariant (value)
+      if (((is_gimple_min_invariant (value)
+	    /* When the parameter is used in a context that forces it to
+	       not be a GIMPLE register avoid substituting something that
+	       is not a decl there.  */
+	    && ! DECL_NOT_GIMPLE_REG_P (p))
 	   || (DECL_P (value) && TREE_READONLY (value))
 	   || (auto_var_in_fn_p (value, id->dst_fn)
 	       && !TREE_ADDRESSABLE (value)))