Index: gcc/testsuite/gfortran.dg/power_8.f90
===================================================================
--- gcc/testsuite/gfortran.dg/power_8.f90	(nonexistent)
+++ gcc/testsuite/gfortran.dg/power_8.f90	(working copy)
@@ -0,0 +1,64 @@
+! { dg-do run }
+! { dg-additional-options "-fdump-tree-original" }
+!
+! PR88579 - Test optimizations for bases that are powers of 2 or -2.
+program p
+  implicit none
+  integer(4) :: i, u
+  integer(1) :: j, v
+  integer(2) :: k, w
+  integer(8) :: z
+  ! Test selected positive bases
+  u = 1
+  do i=1,5
+     u = u * 64_4
+     if (u /= 64_4 ** i) stop 1
+  end do
+  z = 1
+  do i=1,7
+     z = z * 256_8
+     if (z /= 256_8 ** i) stop 2
+  end do
+  z = 1
+  do i=1,3
+     z = z * 65536_8
+     if (z /= 65536_8 ** i) stop 3
+  end do
+  ! Test selected negative bases and integer kind combinations
+  u = 1
+  do i=1,7
+     u = u * (-2_1)
+     if (u /= (-2_1) ** i) stop 4
+  end do
+  v = 1
+  do j=1,7
+     v = v * (-2_1)
+     if (v /= (-2_1) ** j) stop 5
+  end do
+  v = 1
+  do k=1,7
+     v = v * (-2_1)
+     if (v /= (-2_1) ** k) stop 6
+  end do
+  w = 1
+  do k=1,7
+     w = w * (-4_2)
+     if (w /= (-4_2) ** k) stop 7
+  end do
+  w = 1
+  do i=1,5
+     w = w * (-8_2)
+     if (w /= (-8_2) ** i) stop 8
+  end do
+  u = 1
+  do i=1,1
+     u = u * (-HUGE(1_4)/2-1)
+     if (u /= (-HUGE(1_4)/2-1) ** i) stop 9
+  end do
+  z = 1
+  do i=1,7
+     z = z * (-512_8)
+     if (z /= (-512_8) ** i) stop 10
+  end do
+end program p
+! { dg-final { scan-tree-dump-not "_gfortran_pow" "original" } }