diff --git a/llvm/lib/Target/PowerPC/PPCInstrInfo.td b/llvm/lib/Target/PowerPC/PPCInstrInfo.td
index 844ba72d93b1..9edf0ae5d4f4 100644
--- a/llvm/lib/Target/PowerPC/PPCInstrInfo.td
+++ b/llvm/lib/Target/PowerPC/PPCInstrInfo.td
@@ -4627,19 +4627,8 @@ foreach SPRG = 4-7 in {
 
 def : InstAlias<"mtasr $RS", (MTSPR 280, gprc:$RS)>;
 
-def : InstAlias<"mfdec $RT", (MFSPR gprc:$RT, 22)>;
-def : InstAlias<"mtdec $RT", (MTSPR 22, gprc:$RT)>;
-
 def : InstAlias<"mfpvr $RT", (MFSPR gprc:$RT, 287)>;
 
-def : InstAlias<"mfsdr1 $RT", (MFSPR gprc:$RT, 25)>;
-def : InstAlias<"mtsdr1 $RT", (MTSPR 25, gprc:$RT)>;
-
-def : InstAlias<"mfsrr0 $RT", (MFSPR gprc:$RT, 26)>;
-def : InstAlias<"mfsrr1 $RT", (MFSPR gprc:$RT, 27)>;
-def : InstAlias<"mtsrr0 $RT", (MTSPR 26, gprc:$RT)>;
-def : InstAlias<"mtsrr1 $RT", (MTSPR 27, gprc:$RT)>;
-
 def : InstAlias<"tlbie $RB", (TLBIE R0, gprc:$RB)>;
 
 def : InstAlias<"tlbrehi $RS, $A", (TLBRE2 gprc:$RS, gprc:$A, 0)>,