Index: lib/Target/Mips/Mips64InstrInfo.td
===================================================================
--- lib/Target/Mips/Mips64InstrInfo.td
+++ lib/Target/Mips/Mips64InstrInfo.td
@@ -838,7 +838,7 @@
               (SUBu GPR32:$src, GPR32:$src2), sub_32)>;
 def : MipsPat<(i64 (sext (i32 (mul GPR32:$src, GPR32:$src2)))),
               (INSERT_SUBREG (i64 (IMPLICIT_DEF)),
-              (MUL GPR32:$src, GPR32:$src2), sub_32)>;
+              (MUL GPR32:$src, GPR32:$src2), sub_32)>, ISA_MIPS3_NOT_32R6_64R6;
 def : MipsPat<(i64 (sext (i32 (MipsMFHI ACC64:$src)))),
               (INSERT_SUBREG (i64 (IMPLICIT_DEF)),
               (PseudoMFHI ACC64:$src), sub_32)>;
Index: lib/Target/Mips/Mips64r6InstrInfo.td
===================================================================
--- lib/Target/Mips/Mips64r6InstrInfo.td
+++ lib/Target/Mips/Mips64r6InstrInfo.td
@@ -301,6 +301,9 @@
 
 // Patterns used for matching away redundant sign extensions.
 // MIPS32 arithmetic instructions sign extend their result implicitly.
+def : MipsPat<(i64 (sext (i32 (mul GPR32:$src, GPR32:$src2)))),
+              (INSERT_SUBREG (i64 (IMPLICIT_DEF)),
+              (MUL_R6 GPR32:$src, GPR32:$src2), sub_32)>;
 def : MipsPat<(i64 (sext (i32 (sdiv GPR32:$src, GPR32:$src2)))),
               (INSERT_SUBREG (i64 (IMPLICIT_DEF)),
               (DIV GPR32:$src, GPR32:$src2), sub_32)>, ISA_MIPS64R6;