[gcc/devel/c++-coroutines] Fix inliner ICE on alias with flatten attribute [PR92372]

[Iain D Sandoe]

https://gcc.gnu.org/g:f22712bd8a2ed57d3cc7e6fa92730bd5852e27b3

commit f22712bd8a2ed57d3cc7e6fa92730bd5852e27b3
Author: Jan Hubicka <jh@suse.cz>
Date:   Thu Mar 19 17:12:56 2020 +0100

    Fix inliner ICE on alias with flatten attribute [PR92372]
    
    gcc/ChangeLog:
    
    2020-03-19  Jan Hubicka  <hubicka@ucw.cz>
    
            PR ipa/92372
            * cgraphunit.c (process_function_and_variable_attributes): warn
            for flatten attribute on alias.
            * ipa-inline.c (ipa_inline): Do not ICE on flatten attribute on alias.
    
    gcc/testsuite/ChangeLog:
    
    2020-03-19  Jan Hubicka  <hubicka@ucw.cz>
    
            PR ipa/92372
            * gcc.c-torture/pr92372.c: New test.
            * gcc.dg/attr-flatten-1.c: New test.

Diff:
---
 gcc/ChangeLog                         |  7 +++++++
 gcc/cgraphunit.c                      |  8 ++++++++
 gcc/ipa-inline.c                      |  3 +++
 gcc/testsuite/ChangeLog               |  6 ++++++
 gcc/testsuite/gcc.c-torture/pr92372.c | 16 ++++++++++++++++
 gcc/testsuite/gcc.dg/attr-flatten-1.c | 18 ++++++++++++++++++
 6 files changed, 58 insertions(+)

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 6b1b2956e7a..e1a778df202 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,10 @@
+2020-03-19  Jan Hubicka  <hubicka@ucw.cz>
+
+	PR ipa/92372
+	* cgraphunit.c (process_function_and_variable_attributes): warn
+	for flatten attribute on alias.
+	* ipa-inline.c (ipa_inline): Do not ICE on flatten attribute on alias.
+
 2020-03-19  Martin Liska  <mliska@suse.cz>
 
 	* lto-section-in.c: Add ext_symtab.
diff --git a/gcc/cgraphunit.c b/gcc/cgraphunit.c
index fd586366bb9..d7ed405bf2c 100644
--- a/gcc/cgraphunit.c
+++ b/gcc/cgraphunit.c
@@ -851,6 +851,14 @@ process_function_and_variable_attributes (cgraph_node *first,
        node = symtab->next_function (node))
     {
       tree decl = node->decl;
+
+      if (node->alias
+	  && lookup_attribute ("flatten", DECL_ATTRIBUTES (decl)))
+	{
+	  warning_at (DECL_SOURCE_LOCATION (node->decl), OPT_Wattributes,
+		      "%<flatten%>"
+		      " attribute attribute is ignored on aliases");
+	}
       if (DECL_PRESERVE_P (decl))
 	node->mark_force_output ();
       else if (lookup_attribute ("externally_visible", DECL_ATTRIBUTES (decl)))
diff --git a/gcc/ipa-inline.c b/gcc/ipa-inline.c
index 6b6ba9aa4b6..302ce16a646 100644
--- a/gcc/ipa-inline.c
+++ b/gcc/ipa-inline.c
@@ -2634,6 +2634,9 @@ ipa_inline (void)
     {
       node = order[i];
       if (node->definition
+	  /* Do not try to flatten aliases.  These may happen for example when
+	     creating local aliases.  */
+	  && !node->alias
 	  && lookup_attribute ("flatten",
 			       DECL_ATTRIBUTES (node->decl)) != NULL)
 	order[j--] = order[i];
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 58f2e7e7c47..cce16031845 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,9 @@
+2020-03-19  Jan Hubicka  <hubicka@ucw.cz>
+
+	PR ipa/92372
+	* gcc.c-torture/pr92372.c: New test.
+	* gcc.dg/attr-flatten-1.c: New test.
+
 2020-03-19  Jakub Jelinek  <jakub@redhat.com>
 
 	PR tree-optimization/94211
diff --git a/gcc/testsuite/gcc.c-torture/pr92372.c b/gcc/testsuite/gcc.c-torture/pr92372.c
new file mode 100644
index 00000000000..72a13bb16f4
--- /dev/null
+++ b/gcc/testsuite/gcc.c-torture/pr92372.c
@@ -0,0 +1,16 @@
+int fn2(int);
+int fn3(int);
+
+__attribute__((flatten))
+int fn1(int p1)
+{
+  int a = fn2(p1);
+  return fn3(a);
+}
+__attribute__((flatten))
+int fn4(int p1)
+{
+  int j = fn2(p1);
+  return fn3(j);
+}
+
diff --git a/gcc/testsuite/gcc.dg/attr-flatten-1.c b/gcc/testsuite/gcc.dg/attr-flatten-1.c
new file mode 100644
index 00000000000..ecb08fcd2ad
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/attr-flatten-1.c
@@ -0,0 +1,18 @@
+/* { dg-require-alias "" } */
+int fn2(int);
+int fn3(int);
+
+__attribute__((flatten))
+int fn1(int p1)
+{
+  int a = fn2(p1);
+  return fn3(a);
+}
+__attribute__((flatten))
+__attribute__((alias("fn1")))
+int fn4(int p1); /* { dg-warning "ignored" } */
+int
+test ()
+{
+  return fn4(1);
+}