diff --git a/ChangeLog b/ChangeLog
index 27b49cd1b2..9bc63761d6 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,13 @@
 2017-12-01  Joseph Myers  <joseph@codesourcery.com>
 
+	* sysdeps/powerpc/power7/fpu/s_logb.c
+	[LONG_DOUBLE_COMPAT (libm, GLIBC_2_0)] (logbl): Define as compat
+	symbol based on __logb, not on logb.
+	* sysdeps/powerpc/powerpc32/power4/fpu/multiarch/s_logb.c
+	[LONG_DOUBLE_COMPAT (libm, GLIBC_2_0)] (logbl): Likewise.
+	* sysdeps/powerpc/powerpc64/fpu/multiarch/s_logb.c
+	[LONG_DOUBLE_COMPAT (libm, GLIBC_2_0)] (logbl): Likewise.
+
 	* sysdeps/powerpc/fpu/s_rint.c: Include <libm-alias-double.h>.
 	(rint): Define using libm_alias_double.
 	* sysdeps/powerpc/power5+/fpu/s_modf.c: Include
diff --git a/sysdeps/powerpc/power7/fpu/s_logb.c b/sysdeps/powerpc/power7/fpu/s_logb.c
index af74b1d024..1c7a4a850b 100644
--- a/sysdeps/powerpc/power7/fpu/s_logb.c
+++ b/sysdeps/powerpc/power7/fpu/s_logb.c
@@ -75,5 +75,5 @@ weak_alias (__logb, logbl)
 #endif
 
 #if LONG_DOUBLE_COMPAT (libm, GLIBC_2_0)
-compat_symbol (libm, logb, logbl, GLIBC_2_0);
+compat_symbol (libm, __logb, logbl, GLIBC_2_0);
 #endif
diff --git a/sysdeps/powerpc/powerpc32/power4/fpu/multiarch/s_logb.c b/sysdeps/powerpc/powerpc32/power4/fpu/multiarch/s_logb.c
index fddd1ecbec..f178967f0e 100644
--- a/sysdeps/powerpc/powerpc32/power4/fpu/multiarch/s_logb.c
+++ b/sysdeps/powerpc/powerpc32/power4/fpu/multiarch/s_logb.c
@@ -37,5 +37,5 @@ weak_alias (__logb, logbl)
 #endif
 
 #if LONG_DOUBLE_COMPAT (libm, GLIBC_2_0)
-compat_symbol (libm, logb, logbl, GLIBC_2_0);
+compat_symbol (libm, __logb, logbl, GLIBC_2_0);
 #endif
diff --git a/sysdeps/powerpc/powerpc64/fpu/multiarch/s_logb.c b/sysdeps/powerpc/powerpc64/fpu/multiarch/s_logb.c
index d70919e3d4..c2e9f4d3ce 100644
--- a/sysdeps/powerpc/powerpc64/fpu/multiarch/s_logb.c
+++ b/sysdeps/powerpc/powerpc64/fpu/multiarch/s_logb.c
@@ -37,5 +37,5 @@ weak_alias (__logb, logbl)
 #endif
 
 #if LONG_DOUBLE_COMPAT (libm, GLIBC_2_0)
-compat_symbol (libm, logb, logbl, GLIBC_2_0);
+compat_symbol (libm, __logb, logbl, GLIBC_2_0);
 #endif