re PR rtl-optimization/83985 (Compile time hog for 32-bit BE powerpc targets)

	PR rtl-optimization/83985
	* dce.c (deletable_insn_p): Return false for separate shrink wrapping
	REG_CFA_RESTORE insns.
	(delete_unmarked_insns): Don't ignore separate shrink wrapping
	REG_CFA_RESTORE insns here.

	* gcc.dg/pr83985.c: New test.

From-SVN: r257087

gcc/ChangeLog

 2018-01-26  Jakub Jelinek  <jakub@redhat.com>
 
+	PR rtl-optimization/83985
+	* dce.c (deletable_insn_p): Return false for separate shrink wrapping
+	REG_CFA_RESTORE insns.
+	(delete_unmarked_insns): Don't ignore separate shrink wrapping
+	REG_CFA_RESTORE insns here.
+
 	PR c/83989
 	* gimple-ssa-warn-restrict.c (builtin_memref::builtin_memref): Don't
 	use SSA_NAME_VAR as base for SSA_NAMEs with non-NULL SSA_NAME_VAR.

gcc/dce.c

@@ -131,6 +131,12 @@ deletable_insn_p (rtx_insn *insn, bool fast, bitmap arg_stores)
 	     && REGNO (pic_offset_table_rtx) >= FIRST_PSEUDO_REGISTER)
       return false;
 
+  /* Callee-save restores are needed.  */
+  if (RTX_FRAME_RELATED_P (insn)
+      && crtl->shrink_wrapped_separate
+      && find_reg_note (insn, REG_CFA_RESTORE, NULL))
+    return false;
+
   body = PATTERN (insn);
   switch (GET_CODE (body))
     {
@@ -592,15 +598,6 @@ delete_unmarked_insns (void)
 	  if (!dbg_cnt (dce))
 	    continue;
 
-	  if (crtl->shrink_wrapped_separate
-	      && find_reg_note (insn, REG_CFA_RESTORE, NULL))
-	    {
-	      if (dump_file)
-		fprintf (dump_file, "DCE: NOT deleting insn %d, it's a "
-				    "callee-save restore\n", INSN_UID (insn));
-	      continue;
-	    }
-
 	  if (dump_file)
 	    fprintf (dump_file, "DCE: Deleting insn %d\n", INSN_UID (insn));
 

gcc/testsuite/ChangeLog

 2018-01-26  Jakub Jelinek  <jakub@redhat.com>
 
+	PR rtl-optimization/83985
+	* gcc.dg/pr83985.c: New test.
+
 	PR c/83989
 	* c-c++-common/Wrestrict-3.c: New test.
 

gcc/testsuite/gcc.dg/pr83985.c

+/* PR rtl-optimization/83985 */
+/* { dg-do compile } */
+/* { dg-options "-O2" } */
+/* { dg-additional-options "-mcpu=e300c3 -mtune=e300c3" { target { powerpc*-*-* && ilp32 } } } */
+
+long long int v;
+
+void
+foo (int x)
+{
+  if (x == 0)
+    return;
+
+  while (v < 2)
+    {
+      signed char *a;
+      v /= x;
+      a = v == 0 ? (signed char *) &x : (signed char *) &v;
+      ++*a;
+      ++v;
+    }
+
+  while (1)
+    ;
+}