[PATCH] Fix calls.c for a _complex type (PR ipa/80104).

[Martin Liška]

Hello.

Briefly described in the PR, running ICF (without any optimization level) can 
create a thunk call
that does not use an SSA_NAME which is a default def of an argument of the 
caller:

c (complex float b)
{
  complex float arg.1;
  float retval.0;

  <bb 2> [100.00%]:
  arg.1_2 = b;
  retval.0_4 = a (arg.1_2); [tail call]
  return retval.0_4;

}

The "arg" variable creation was introduced by Jason in r207301.
As complex type is passed as invisible reference, we need to find address of 
the argument.
Thus I'm suggesting to find it alternatively via SSA_NAME_DEF_STMT.

Patch can bootstrap on ppc64le-redhat-linux and survives regression tests. And 
fixes the ICE
on s390x cross compiler.

Ready to be installed?
Martin

>From 6624f7b292d174b5c0c1a276c1ed919c9930dca4 Mon Sep 17 00:00:00 2001
From: marxin <mli...@suse.cz>
Date: Thu, 23 Mar 2017 16:03:04 +0100
Subject: [PATCH] Fix calls.c for a _complex type (PR ipa/80104).

gcc/ChangeLog:

2017-03-23  Martin Liska  <mli...@suse.cz>

	PR ipa/80104
	* calls.c (initialize_argument_information): Find real argument
	of a gimple call (of thunk) in order to find address of the
	argument.

gcc/testsuite/ChangeLog:

2017-03-23  Martin Liska  <mli...@suse.cz>

	* gcc.dg/ipa/pr80104.c: New test.
---
 gcc/calls.c                        | 11 +++++++++--
 gcc/testsuite/gcc.dg/ipa/pr80104.c | 15 +++++++++++++++
 2 files changed, 24 insertions(+), 2 deletions(-)
 create mode 100644 gcc/testsuite/gcc.dg/ipa/pr80104.c

diff --git a/gcc/calls.c b/gcc/calls.c
index 61caf4ca752..0ee21d9e951 100644
--- a/gcc/calls.c
+++ b/gcc/calls.c
@@ -1745,8 +1745,15 @@ initialize_argument_information (int num_actuals ATTRIBUTE_UNUSED,
 		 address.  */
 	      if (TREE_CODE (args[i].tree_value) == SSA_NAME)
 		{
-		  gcc_assert (SSA_NAME_IS_DEFAULT_DEF (args[i].tree_value));
-		  args[i].tree_value = SSA_NAME_VAR (args[i].tree_value);
+		  if (SSA_NAME_IS_DEFAULT_DEF (args[i].tree_value))
+		    args[i].tree_value = SSA_NAME_VAR (args[i].tree_value);
+		  else
+		  {
+		    gimple *g = SSA_NAME_DEF_STMT (args[i].tree_value);
+		    if (gimple_assign_single_p (g))
+		      args[i].tree_value = gimple_assign_rhs1 (g);
+		  }
+
 		  gcc_assert (TREE_CODE (args[i].tree_value) == PARM_DECL);
 		}
 	      /* Argument setup code may have copied the value to register.  We
diff --git a/gcc/testsuite/gcc.dg/ipa/pr80104.c b/gcc/testsuite/gcc.dg/ipa/pr80104.c
new file mode 100644
index 00000000000..7e75c9907e7
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/ipa/pr80104.c
@@ -0,0 +1,15 @@
+/* PR ipa/80104 */
+/* { dg-do compile } */
+/* { dg-options "-fipa-icf" } */
+
+float
+a (_Complex float b)
+{
+  return *&b;
+}
+
+float
+c (_Complex float b)
+{
+  return (&b)[0];
+}
-- 
2.12.0