MIPS: Fix __builtin_longjmp (PR 64242)

The problem here is mips has its own builtin_longjmp
pattern and it was not fixed when expand_builtin_longjmp
was fixed.  We need to read the new fp and gp before
restoring the stack as the buffer might be a local
variable.

2020-08-25  Andrew Pinski  <apinski@marvell.com>

gcc/ChangeLog:

	PR middle-end/64242
	* config/mips/mips.md (builtin_longjmp): Restore the frame
	pointer and stack pointer and gp.

diff --git a/gcc/config/mips/mips.md b/gcc/config/mips/mips.md
index 6383a31a5e396a4ad00f15a09dfe1331ccb35dc6..2e75a720fa9bd5f2873a747e3767ba0d4d6c146e 100644 (file)
--- a/gcc/config/mips/mips.md
+++ b/gcc/config/mips/mips.md
@@ -6562,9 +6562,19 @@
 
   /* This bit is similar to expand_builtin_longjmp except that it
      restores $gp as well.  */
-  mips_emit_move (hard_frame_pointer_rtx, fp);
   mips_emit_move (pv, lab);
+  /* Restore the frame pointer and stack pointer and gp.  We must use a
+     temporary since the setjmp buffer may be a local.  */
+  fp = copy_to_reg (fp);
+  gpv = copy_to_reg (gpv);
   emit_stack_restore (SAVE_NONLOCAL, stack);
+
+  /* Ensure the frame pointer move is not optimized.  */
+  emit_insn (gen_blockage ());
+  emit_clobber (hard_frame_pointer_rtx);
+  emit_clobber (frame_pointer_rtx);
+  emit_clobber (gp);
+  mips_emit_move (hard_frame_pointer_rtx, fp);
   mips_emit_move (gp, gpv);
   emit_use (hard_frame_pointer_rtx);
   emit_use (stack_pointer_rtx);