re PR target/77904 ([ARM Cortex-M0] Frame pointer thrashes registers if assembly…

re PR target/77904 ([ARM Cortex-M0] Frame pointer thrashes registers if assembly statements with "sp" clobber are used)

2016-11-22  Thomas Preud'homme  <thomas.preudhomme@arm.com>

    gcc/
    PR target/77904
    * config/arm/arm.c (thumb1_compute_save_reg_mask): Mark frame pointer
    in save register mask if it is needed.

    gcc/testsuite/
    PR target/77904
    * gcc.target/arm/pr77904.c: New test.

From-SVN: r242693

gcc/ChangeLog

+2016-11-22  Thomas Preud'homme  <thomas.preudhomme@arm.com>
+
+	PR target/77904
+	* config/arm/arm.c (thumb1_compute_save_reg_mask): Mark frame pointer
+	in save register mask if it is needed.
+
 2016-11-22  Jakub Jelinek  <jakub@redhat.com>
 
 	PR tree-optimization/78436

gcc/config/arm/arm.c

@@ -18275,6 +18275,10 @@ thumb1_compute_save_reg_mask (void)
     if (df_regs_ever_live_p (reg) && callee_saved_reg_p (reg))
       mask |= 1 << reg;
 
+  /* Handle the frame pointer as a special case.  */
+  if (frame_pointer_needed)
+    mask |= 1 << HARD_FRAME_POINTER_REGNUM;
+
   if (flag_pic
       && !TARGET_SINGLE_PIC_BASE
       && arm_pic_register != INVALID_REGNUM

gcc/testsuite/ChangeLog

+2016-11-22  Thomas Preud'homme  <thomas.preudhomme@arm.com>
+
+	PR target/77904
+	* gcc.target/arm/pr77904.c: New test.
+
 2016-11-22  Toma Tabacu  <toma.tabacu@imgtec.com>
 
 	* gcc.target/mips/interrupt_handler-bug-1.c (dg-options): Add

gcc/testsuite/gcc.target/arm/pr77904.c

+/* { dg-do run } */
+/* { dg-options "-O2" } */
+
+__attribute__ ((noinline, noclone)) void
+clobber_sp (void)
+{
+  __asm volatile ("" : : : "sp");
+}
+
+int
+main (void)
+{
+  int ret;
+
+  __asm volatile ("mov\tr4, #0xf4\n\t"
+		  "mov\tr5, #0xf5\n\t"
+		  "mov\tr6, #0xf6\n\t"
+		  "mov\tr7, #0xf7\n\t"
+		  "mov\tr0, #0xf8\n\t"
+		  "mov\tr8, r0\n\t"
+		  "mov\tr0, #0xfa\n\t"
+		  "mov\tr10, r0"
+		  : : : "r0", "r4", "r5", "r6", "r7", "r8", "r10");
+  clobber_sp ();
+
+  __asm volatile ("cmp\tr4, #0xf4\n\t"
+		  "bne\tfail\n\t"
+		  "cmp\tr5, #0xf5\n\t"
+		  "bne\tfail\n\t"
+		  "cmp\tr6, #0xf6\n\t"
+		  "bne\tfail\n\t"
+		  "cmp\tr7, #0xf7\n\t"
+		  "bne\tfail\n\t"
+		  "mov\tr0, r8\n\t"
+		  "cmp\tr0, #0xf8\n\t"
+		  "bne\tfail\n\t"
+		  "mov\tr0, r10\n\t"
+		  "cmp\tr0, #0xfa\n\t"
+		  "bne\tfail\n\t"
+		  "mov\t%0, #1\n"
+		  "fail:\n\t"
+		  "sub\tr0, #1"
+		  : "=r" (ret) : :);
+  return ret;
+}