diff --git a/CMakeLists.txt b/CMakeLists.txt
index 208da7b41c..ddb55dcbed 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -111,6 +111,8 @@ if(CMAKE_Fortran_COMPILER_ID STREQUAL GNU)
   list(APPEND f90flags -cpp -std=f2008 -fbacktrace -O2)
   list(APPEND cflags -cpp -std=c99 -O2)
   if(debug)
+    list(REMOVE_ITEM f90flags -O2)
+    list(REMOVE_ITEM cflags -O2)
     list(APPEND f90flags -g -Wall -pedantic -fbounds-check
       -ffpe-trap=invalid,overflow,underflow)
     list(APPEND cflags -g -Wall -pedantic -fbounds-check)
@@ -144,8 +146,8 @@ elseif(CMAKE_Fortran_COMPILER_ID STREQUAL Intel)
   list(APPEND cflags -std=c99)
   if(debug)
     list(APPEND f90flags -g -warn -ftrapuv -fp-stack-check
-      "-check all" -fpe0)
-    list(APPEND cflags -g -w3 -ftrapuv -fp-stack-check)
+      "-check all" -fpe0 -O0)
+    list(APPEND cflags -g -w3 -ftrapuv -fp-stack-check -O0)
     list(APPEND ldflags -g)
   endif()
   if(profile)
@@ -184,7 +186,8 @@ elseif(CMAKE_Fortran_COMPILER_ID STREQUAL XL)
   list(APPEND f90flags -O2)
   add_definitions(-DNO_F2008)
   if(debug)
-    list(APPEND f90flags -g -C -qflag=i:i -u)
+    list(REMOVE_ITEM f90flags -O2)
+    list(APPEND f90flags -g -C -qflag=i:i -u -O0)
     list(APPEND ldflags -g)
   endif()
   if(profile)