diff --git a/gcc/testsuite/gfortran.dg/pr25623-2.f90 b/gcc/testsuite/gfortran.dg/pr25623-2.f90
new file mode 100644
index 00000000000..57679e0d6ed
--- /dev/null
+++ b/gcc/testsuite/gfortran.dg/pr25623-2.f90
@@ -0,0 +1,19 @@
+! { dg-do compile }
+! { dg-options "-fdump-tree-optimized-blocks -O3" }
+
+SUBROUTINE S42(a,b,c,N)
+ IMPLICIT NONE
+ integer :: N
+ real*8  :: a(N),b(N),c(N),tmp,tmp2,tmp4
+ real*8, parameter :: p=1.0D0/3.0D0
+ integer :: i
+ c=0.0D0
+ DO i=1,N
+   tmp=a(i)**p ! could even be done with a cube root
+   tmp2=tmp*tmp
+   tmp4=tmp2*tmp2
+   b(i)=b(i)+tmp4
+   c(i)=c(i)+tmp2
+ ENDDO
+END SUBROUTINE
+! { dg-final { scan-tree-dump-not "Invalid sum" "optimized" } }
diff --git a/gcc/tree-ssa-loop-ch.cc b/gcc/tree-ssa-loop-ch.cc
index 291f2dbcab9..72792cec21f 100644
--- a/gcc/tree-ssa-loop-ch.cc
+++ b/gcc/tree-ssa-loop-ch.cc
@@ -422,6 +422,7 @@ ch_base::copy_headers (function *fun)
 	{
 	  if (dump_file && (dump_flags & TDF_DETAILS))
 	    fprintf (dump_file, "Loop %d never loops.\n", loop->num);
+	  scale_loop_profile (loop, profile_probability::always (), 0);
 	  loops_to_unloop.safe_push (loop);
 	  loops_to_unloop_nunroll.safe_push (0);
 	  continue;
@@ -666,6 +667,7 @@ ch_base::copy_headers (function *fun)
 	{
 	  if (dump_file && (dump_flags & TDF_DETAILS))
 	    fprintf (dump_file, "Loop %d no longer loops.\n", loop->num);
+	  scale_loop_profile (loop, profile_probability::always (), 0);
 	  loops_to_unloop.safe_push (loop);
 	  loops_to_unloop_nunroll.safe_push (0);
 	}
diff --git a/gcc/tree-ssa-loop-ivcanon.cc b/gcc/tree-ssa-loop-ivcanon.cc
index 9e119eb37f3..0117dbfc91b 100644
--- a/gcc/tree-ssa-loop-ivcanon.cc
+++ b/gcc/tree-ssa-loop-ivcanon.cc
@@ -906,6 +906,10 @@ try_unroll_loop_completely (class loop *loop,
       if (may_be_zero)
 	bitmap_clear_bit (wont_exit, 1);
 
+      /* If loop was originally estimated to iterate too many times,
+	 reduce the profile to avoid new profile inconsistencies.  */
+      scale_loop_profile (loop, profile_probability::always (), n_unroll);
+
       if (!gimple_duplicate_loop_body_to_header_edge (
 	    loop, loop_preheader_edge (loop), n_unroll, wont_exit, exit,
 	    &edges_to_remove,
@@ -919,6 +923,8 @@ try_unroll_loop_completely (class loop *loop,
 
       free_original_copy_tables ();
     }
+  else
+    scale_loop_profile (loop, profile_probability::always (), 0);
 
   /* Remove the conditional from the last copy of the loop.  */
   if (edge_to_cancel)