diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 0a7e68afafe..00919b3f035 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,5 +1,10 @@
 2003-02-27  David Edelsohn  <edelsohn@gnu.org>
 
+	* config/rs6000/aix43.h (ASM_SPEC): Only emit -mppc64 if no -mcpu
+	option.
+	(ASM_CPU_SPEC): Use -m620 for Power3, Power4, 620, 630.
+	* config/rs6000/aix51.h: Same.
+	* config/rs6000/aix52.h: Same.
 	* config/rs6000/power4.md: Additional VMX bypasses.
 
 2003-02-27   Geert Bosch <bosch@gnat.com>
diff --git a/gcc/config/rs6000/aix43.h b/gcc/config/rs6000/aix43.h
index 19cadd85586..2c8900c0008 100644
--- a/gcc/config/rs6000/aix43.h
+++ b/gcc/config/rs6000/aix43.h
@@ -60,7 +60,7 @@ do {									\
 } while (0);
 
 #undef ASM_SPEC
-#define ASM_SPEC "-u %{maix64:-a64 -mppc64} %(asm_cpu)"
+#define ASM_SPEC "-u %{maix64:-a64 %{!mcpu*:-mppc64}} %(asm_cpu)"
 
 /* Common ASM definitions used by ASM_SPEC amongst the various targets
    for handling -mcpu=xxx switches.  */
@@ -75,8 +75,8 @@ do {									\
 %{mcpu=common: -mcom} \
 %{mcpu=power: -mpwr} \
 %{mcpu=power2: -mpwr2} \
-%{mcpu=power3: -m604} \
-%{mcpu=power4: -m604} \
+%{mcpu=power3: -m620} \
+%{mcpu=power4: -m620} \
 %{mcpu=powerpc: -mppc} \
 %{mcpu=rios: -mpwr} \
 %{mcpu=rios1: -mpwr} \
@@ -90,8 +90,8 @@ do {									\
 %{mcpu=603e: -m603} \
 %{mcpu=604: -m604} \
 %{mcpu=604e: -m604} \
-%{mcpu=620: -mppc} \
-%{mcpu=630: -m604}"
+%{mcpu=620: -m620} \
+%{mcpu=630: -m620}"
 
 #undef	ASM_DEFAULT_SPEC
 #define ASM_DEFAULT_SPEC "-mcom"
diff --git a/gcc/config/rs6000/aix51.h b/gcc/config/rs6000/aix51.h
index 201b2addfb5..dfe9cf2333a 100644
--- a/gcc/config/rs6000/aix51.h
+++ b/gcc/config/rs6000/aix51.h
@@ -60,7 +60,7 @@ do {									\
 } while (0);
 
 #undef ASM_SPEC
-#define ASM_SPEC "-u %{maix64:-a64 -mppc64} %(asm_cpu)"
+#define ASM_SPEC "-u %{maix64:-a64 %{!mcpu*:-mppc64}} %(asm_cpu)"
 
 /* Common ASM definitions used by ASM_SPEC amongst the various targets
    for handling -mcpu=xxx switches.  */
@@ -75,8 +75,8 @@ do {									\
 %{mcpu=common: -mcom} \
 %{mcpu=power: -mpwr} \
 %{mcpu=power2: -mpwr2} \
-%{mcpu=power3: -m604} \
-%{mcpu=power4: -m604} \
+%{mcpu=power3: -m620} \
+%{mcpu=power4: -m620} \
 %{mcpu=powerpc: -mppc} \
 %{mcpu=rios: -mpwr} \
 %{mcpu=rios1: -mpwr} \
@@ -90,8 +90,8 @@ do {									\
 %{mcpu=603e: -m603} \
 %{mcpu=604: -m604} \
 %{mcpu=604e: -m604} \
-%{mcpu=620: -mppc} \
-%{mcpu=630: -m604}"
+%{mcpu=620: -m620} \
+%{mcpu=630: -m620}"
 
 #undef	ASM_DEFAULT_SPEC
 #define ASM_DEFAULT_SPEC "-mcom"
diff --git a/gcc/config/rs6000/aix52.h b/gcc/config/rs6000/aix52.h
index da7e0366c97..9d72e71e4bd 100644
--- a/gcc/config/rs6000/aix52.h
+++ b/gcc/config/rs6000/aix52.h
@@ -60,7 +60,7 @@ do {									\
 } while (0);
 
 #undef ASM_SPEC
-#define ASM_SPEC "-u %{maix64:-a64 -mppc64} %(asm_cpu)"
+#define ASM_SPEC "-u %{maix64:-a64 %{!mcpu*:-mppc64}} %(asm_cpu)"
 
 /* Common ASM definitions used by ASM_SPEC amongst the various targets
    for handling -mcpu=xxx switches.  */
@@ -69,16 +69,16 @@ do {									\
 "%{!mcpu*: %{!maix64: \
   %{mpowerpc64: -mppc64} \
   %{!mpower64: %(asm_default)}}} \
-%{mcpu=power3: -m604} \
-%{mcpu=power4: -m604} \
+%{mcpu=power3: -m620} \
+%{mcpu=power4: -m620} \
 %{mcpu=powerpc: -mppc} \
 %{mcpu=rs64a: -mppc} \
 %{mcpu=603: -m603} \
 %{mcpu=603e: -m603} \
 %{mcpu=604: -m604} \
 %{mcpu=604e: -m604} \
-%{mcpu=620: -mppc} \
-%{mcpu=630: -m604}"
+%{mcpu=620: -m620} \
+%{mcpu=630: -m620}"
 
 #undef	ASM_DEFAULT_SPEC
 #define ASM_DEFAULT_SPEC "-mppc"