re PR rtl-optimization/38644 (Optimization flag -O1 -fschedule-insns2 causes wrong code)

2011-11-04  Jiangning Liu  <jiangning.liu@arm.com>

	PR rtl-optimization/38644
	* config/arm/arm.c (thumb1_expand_epilogue): Add memory barrier
	for epilogue having stack adjustment.

	testcase:
	* gcc.target/arm/stack-red-zone.c: New.

From-SVN: r180964

gcc/ChangeLog

+2011-11-04  Jiangning Liu  <jiangning.liu@arm.com>
+
+	PR rtl-optimization/38644
+	* config/arm/arm.c (thumb1_expand_epilogue): Add memory barrier
+	for epilogue having stack adjustment.
+
 2011-11-04  Georg-Johann Lay  <avr@gjlay.de>
 
 	PR target/50931

gcc/config/arm/arm.c

@@ -22216,6 +22216,8 @@ thumb1_expand_epilogue (void)
   gcc_assert (amount >= 0);
   if (amount)
     {
+      emit_insn (gen_blockage ());
+
       if (amount < 512)
 	emit_insn (gen_addsi3 (stack_pointer_rtx, stack_pointer_rtx,
 			       GEN_INT (amount)));

gcc/testsuite/ChangeLog

+2011-11-04  Jiangning Liu  <jiangning.liu@arm.com>
+
+	PR rtl-optimization/38644
+	* gcc.target/arm/stack-red-zone.c: New.
+
 2011-11-04  Paolo Carlini  <paolo.carlini@oracle.com>
 
 	PR c++/48420

gcc/testsuite/gcc.target/arm/stack-red-zone.c

+/* No stack red zone.  PR38644.  */
+/* { dg-options "-mthumb -O2" } */
+/* { dg-final { scan-assembler "ldrb\[^\n\]*\\n\[\t \]*add\[\t \]*sp" } } */
+
+extern int doStreamReadBlock (int *, char *, int size, int);
+
+char readStream (int *s)
+{
+       char c = 0;
+       doStreamReadBlock (s, &c, 1, *s);
+       return c;
+}