[ARM/AArch64] PR 68088: Fix RTL checking ICE due to subregs inside accumulator forwarding check

        PR target/68088
        * config/arm/aarch-common.c (aarch_accumulator_forwarding): Strip
        subregs from accumulator and make sure it's a register.

        * gcc.dg/pr68088_1.c: New test.

From-SVN: r229845

gcc/ChangeLog

+2015-11-06  Kyrylo Tkachov  <kyrylo.tkachov@arm.com>
+
+	PR target/68088
+	* config/arm/aarch-common.c (aarch_accumulator_forwarding): Strip
+	subregs from accumulator and make sure it's a register.
+
 2015-11-06  Simon Dardis  <simon.dardis@imgtec.com>
 
 	* config/mips/loongson.md (vec_loongson_extract_lo_<mode>): New, extract

gcc/config/arm/aarch-common.c

@@ -460,6 +460,12 @@ aarch_accumulator_forwarding (rtx_insn *producer, rtx_insn *consumer)
 	return 0;
     }
 
+  if (GET_CODE (accumulator) == SUBREG)
+    accumulator = SUBREG_REG (accumulator);
+
+  if (!REG_P (accumulator))
+    return 0;
+
   return (REGNO (dest) == REGNO (accumulator));
 }
 

gcc/testsuite/ChangeLog

+2015-11-06  Kyrylo Tkachov  <kyrylo.tkachov@arm.com>
+
+	PR target/68088
+	* gcc.dg/pr68088_1.c: New test.
+
 2015-11-06  Richard Biener  <rguenther@suse.de>
 
 	* gcc.dg/vect/bb-slp-38.c: New testcase.

gcc/testsuite/gcc.dg/pr68088_1.c

+/* { dg-do compile } */
+/* { dg-options "-O2" } */
+
+void bar (unsigned long);
+
+void
+foo (unsigned long aul, unsigned m, unsigned i)
+{
+  while (1)
+    {
+      aul += i;
+      i = aul % m;
+      bar (aul);
+    }
+}