[ARM] PR target/70830: Avoid POP-{reglist}^ when returning from interrupt handlers

	PR target/70830
	* config/arm/arm.c (arm_output_multireg_pop): Avoid POP instruction
	when popping the PC and within an interrupt handler routine.
	Add missing tab to output of "ldmfd".
	(output_return_instruction): Output LDMFD with SP update rather
	than POP when returning from interrupt handler.

	* gcc.target/arm/interrupt-1.c: Change dg-compile to dg-assemble.
	Add -save-temps to dg-options.
	Scan for ldmfd rather than pop instruction.
	* gcc.target/arm/interrupt-2.c: Likewise.
	* gcc.target/arm/pr70830.c: New test.

From-SVN: r236169

gcc/ChangeLog

+2016-05-12  Kyrylo Tkachov  <kyrylo.tkachov@arm.com>
+
+	PR target/70830
+	* config/arm/arm.c (arm_output_multireg_pop): Avoid POP instruction
+	when popping the PC and within an interrupt handler routine.
+	Add missing tab to output of "ldmfd".
+	(output_return_instruction): Output LDMFD with SP update rather
+	than POP when returning from interrupt handler.
+
 2016-05-12  Jakub Jelinek  <jakub@redhat.com>
 
 	* config/i386/i386.md (isa): Add x64_avx512dq, enable if

gcc/config/arm/arm.c

@@ -17755,6 +17755,7 @@ arm_output_multireg_pop (rtx *operands, bool return_pc, rtx cond, bool reverse,
   int num_saves = XVECLEN (operands[0], 0);
   unsigned int regno;
   unsigned int regno_base = REGNO (operands[1]);
+  bool interrupt_p = IS_INTERRUPT (arm_current_func_type ());
 
   offset = 0;
   offset += update ? 1 : 0;
@@ -17772,7 +17773,8 @@ arm_output_multireg_pop (rtx *operands, bool return_pc, rtx cond, bool reverse,
     }
 
   conditional = reverse ? "%?%D0" : "%?%d0";
-  if ((regno_base == SP_REGNUM) && update)
+  /* Can't use POP if returning from an interrupt.  */
+  if ((regno_base == SP_REGNUM) && !(interrupt_p && return_pc))
     {
       sprintf (pattern, "pop%s\t{", conditional);
     }
@@ -17781,11 +17783,8 @@ arm_output_multireg_pop (rtx *operands, bool return_pc, rtx cond, bool reverse,
       /* Output ldmfd when the base register is SP, otherwise output ldmia.
          It's just a convention, their semantics are identical.  */
       if (regno_base == SP_REGNUM)
-	  /* update is never true here, hence there is no need to handle
-	     pop here.  */
-	sprintf (pattern, "ldmfd%s", conditional);
-
-      if (update)
+	sprintf (pattern, "ldmfd%s\t", conditional);
+      else if (update)
 	sprintf (pattern, "ldmia%s\t", conditional);
       else
 	sprintf (pattern, "ldm%s\t", conditional);
@@ -17811,7 +17810,7 @@ arm_output_multireg_pop (rtx *operands, bool return_pc, rtx cond, bool reverse,
 
   strcat (pattern, "}");
 
-  if (IS_INTERRUPT (arm_current_func_type ()) && return_pc)
+  if (interrupt_p && return_pc)
     strcat (pattern, "^");
 
   output_asm_insn (pattern, &cond);
@@ -19622,8 +19621,12 @@ output_return_instruction (rtx operand, bool really_return, bool reverse,
 		  sprintf (instr, "ldmfd%s\t%%|sp, {", conditional);
 		}
 	    }
+	  /* For interrupt returns we have to use an LDM rather than
+	     a POP so that we can use the exception return variant.  */
+	  else if (IS_INTERRUPT (func_type))
+	    sprintf (instr, "ldmfd%s\t%%|sp!, {", conditional);
 	  else
-	      sprintf (instr, "pop%s\t{", conditional);
+	    sprintf (instr, "pop%s\t{", conditional);
 
 	  p = instr + strlen (instr);
 

gcc/testsuite/ChangeLog

+2016-05-12  Kyrylo Tkachov  <kyrylo.tkachov@arm.com>
+
+	PR target/70830
+	* gcc.target/arm/interrupt-1.c: Change dg-compile to dg-assemble.
+	Add -save-temps to dg-options.
+	Scan for ldmfd rather than pop instruction.
+	* gcc.target/arm/interrupt-2.c: Likewise.
+	* gcc.target/arm/pr70830.c: New test.
+
 2016-05-12  Jakub Jelinek  <jakub@redhat.com>
 
 	* gcc.target/i386/avx512bw-vpextr-1.c: New test.

gcc/testsuite/gcc.target/arm/interrupt-1.c

 /* Verify that prologue and epilogue are correct for functions with
    __attribute__ ((interrupt)).  */
-/* { dg-do compile } */
+/* { dg-do assemble } */
 /* { dg-require-effective-target arm_nothumb } */
-/* { dg-options "-O0 -marm" } */
+/* { dg-options "-O0 -marm -save-temps" } */
 
 /* This test is not valid when -mthumb.  */
 extern void bar (int);
@@ -14,4 +14,4 @@ void foo ()
 }
 
 /* { dg-final { scan-assembler "push\t{r0, r1, r2, r3, r4, fp, ip, lr}" } } */
-/* { dg-final { scan-assembler "pop\t{r0, r1, r2, r3, r4, fp, ip, pc}\\^" } } */
+/* { dg-final { scan-assembler "ldmfd\tsp!, {r0, r1, r2, r3, r4, fp, ip, pc}\\^" } } */

gcc/testsuite/gcc.target/arm/interrupt-2.c

 /* Verify that prologue and epilogue are correct for functions with
    __attribute__ ((interrupt)).  */
-/* { dg-do compile } */
+/* { dg-do assemble } */
 /* { dg-require-effective-target arm_nothumb } */
-/* { dg-options "-O1 -marm" } */
+/* { dg-options "-O1 -marm -save-temps" } */
 
 /* This test is not valid when -mthumb.  */
 extern void bar (int);
@@ -16,4 +16,4 @@ void test()
 }
 
 /* { dg-final { scan-assembler "push\t{r0, r1, r2, r3, r4, r5, ip, lr}" } } */
-/* { dg-final { scan-assembler "pop\t{r0, r1, r2, r3, r4, r5, ip, pc}\\^" } } */
+/* { dg-final { scan-assembler "ldmfd\tsp!, {r0, r1, r2, r3, r4, r5, ip, pc}\\^" } } */

gcc/testsuite/gcc.target/arm/pr70830.c

+/* PR target/70830.  */
+/* { dg-do assemble } */
+/* { dg-require-effective-target arm_arm_ok } */
+/* { dg-options "-Os -marm -save-temps" } */
+
+/* This test is not valid when -mthumb.  */
+
+extern void prints (char *);
+
+void __attribute__ ((interrupt ("IRQ"))) dm3730_IRQHandler(void)
+{
+    prints("IRQ" );
+}
+/* { dg-final { scan-assembler "ldmfd\tsp!, {r0, r1, r2, r3, ip, pc}\\^" } } */