From 0898c74df400ebd92a991b6deb8e07a649b67d94 Mon Sep 17 00:00:00 2001
From: Georg-Johann Lay <avr@gjlay.de>
Date: Mon, 6 Feb 2017 13:38:56 +0000
Subject: [PATCH] re PR rtl-optimization/78883 ([avr] ICE triggered by change
 to combine.c (r243578))

gcc/
	PR target/78883
	* config/avr/avr.c (rtl-iter.h): Include it.
	(TARGET_LEGITIMATE_COMBINED_INSN): New hook define...
	(avr_legitimate_combined_insn): ...and implementation.
gcc/testsuite/
	PR target/78883
	* gcc.c-torture/compile/pr78883.c: New test.

From-SVN: r245209
---
 gcc/ChangeLog                                 |  2 ++
 gcc/config/avr/avr.c                          | 32 +++++++++++++++++++
 gcc/testsuite/ChangeLog                       |  5 +++
 gcc/testsuite/gcc.c-torture/compile/pr78883.c | 12 +++++++
 4 files changed, 51 insertions(+)
 create mode 100644 gcc/testsuite/gcc.c-torture/compile/pr78883.c

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 17f415a5ff3..759ab99f1ec 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,5 @@
+2017-02-06  Georg-Johann Lay  <avr@gjlay.de>
+
 2017-02-06  Dominik Vogt  <vogt@linux.vnet.ibm.com>
 
 	* config/s390/predicates.md ("larl_operand"): Use macros from hwint.h.
diff --git a/gcc/config/avr/avr.c b/gcc/config/avr/avr.c
index 9dc7fa0a79a..cde63f10e63 100644
--- a/gcc/config/avr/avr.c
+++ b/gcc/config/avr/avr.c
@@ -49,6 +49,7 @@
 #include "context.h"
 #include "tree-pass.h"
 #include "print-rtl.h"
+#include "rtl-iter.h"
 
 /* This file should be included last.  */
 #include "target-def.h"
@@ -12823,6 +12824,34 @@ avr_convert_to_type (tree type, tree expr)
 }
 
 
+/* Implement `TARGET_LEGITIMATE_COMBINED_INSN'.  */
+
+/* PR78883: Filter out paradoxical SUBREGs of MEM which are not handled
+   properly by following passes.  As INSN_SCHEDULING is off and hence
+   general_operand accepts such expressions, ditch them now.  */
+
+static bool
+avr_legitimate_combined_insn (rtx_insn *insn)
+{
+  subrtx_iterator::array_type array;
+
+  FOR_EACH_SUBRTX (iter, array, PATTERN (insn), NONCONST)
+    {
+      const_rtx op = *iter;
+
+      if (SUBREG_P (op)
+          && MEM_P (SUBREG_REG (op))
+          && (GET_MODE_SIZE (GET_MODE (op))
+              > GET_MODE_SIZE (GET_MODE (SUBREG_REG (op)))))
+        {
+          return false;
+        }
+    }
+
+  return true;
+}
+
+
 /* PR63633: The middle-end might come up with hard regs as input operands.
 
    RMASK is a bit mask representing a subset of hard registers R0...R31:
@@ -14364,6 +14393,9 @@ avr_fold_builtin (tree fndecl, int n_args ATTRIBUTE_UNUSED, tree *arg,
 #define TARGET_USE_BY_PIECES_INFRASTRUCTURE_P \
   avr_use_by_pieces_infrastructure_p
 
+#undef  TARGET_LEGITIMATE_COMBINED_INSN
+#define TARGET_LEGITIMATE_COMBINED_INSN avr_legitimate_combined_insn
+
 struct gcc_target targetm = TARGET_INITIALIZER;
 
 
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 3214eef3bda..2396bd0e834 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2017-02-06  Georg-Johann Lay  <avr@gjlay.de>
+
+	PR target/78883
+	* gcc.c-torture/compile/pr78883.c: New test.
+
 2017-02-05  Jan Hubicka  <hubicka@ucw.cz>
 
 	PR tree-ssa/79347
diff --git a/gcc/testsuite/gcc.c-torture/compile/pr78883.c b/gcc/testsuite/gcc.c-torture/compile/pr78883.c
new file mode 100644
index 00000000000..8401f885058
--- /dev/null
+++ b/gcc/testsuite/gcc.c-torture/compile/pr78883.c
@@ -0,0 +1,12 @@
+/* { dg-do compile } */
+
+int foo (int *p)
+{
+  int i;
+  for (i = 0; i < 5; i++)
+    {
+      if (p[i] & 1)
+        return i;
+    }
+  return -1;
+}
-- 
2.30.2