Index: llvm/trunk/lib/Target/AArch64/AArch64InstrInfo.td
===================================================================
--- llvm/trunk/lib/Target/AArch64/AArch64InstrInfo.td
+++ llvm/trunk/lib/Target/AArch64/AArch64InstrInfo.td
@@ -613,10 +613,12 @@
           (SUBSWrs GPR32:$Rn, arith_shifted_reg32:$Rm)>;
 def : Pat<(sub GPR64:$Rn, arith_shifted_reg64:$Rm),
           (SUBSXrs GPR64:$Rn, arith_shifted_reg64:$Rm)>;
+let AddedComplexity = 1 in {
 def : Pat<(sub GPR32sp:$R2, arith_extended_reg32<i32>:$R3),
           (SUBSWrx GPR32sp:$R2, arith_extended_reg32<i32>:$R3)>;
 def : Pat<(sub GPR64sp:$R2, arith_extended_reg32to64<i64>:$R3),
           (SUBSXrx GPR64sp:$R2, arith_extended_reg32to64<i64>:$R3)>;
+}
 
 // Because of the immediate format for add/sub-imm instructions, the
 // expression (add x, -1) must be transformed to (SUB{W,X}ri x, 1).
Index: llvm/trunk/test/CodeGen/AArch64/addsub_ext.ll
===================================================================
--- llvm/trunk/test/CodeGen/AArch64/addsub_ext.ll
+++ llvm/trunk/test/CodeGen/AArch64/addsub_ext.ll
@@ -80,6 +80,64 @@
     ret void
 }
 
+define void @sub_i8rhs() minsize {
+; CHECK-LABEL: sub_i8rhs:
+    %val8_tmp = load i8, i8* @var8
+    %lhs32 = load i32, i32* @var32
+    %lhs64 = load i64, i64* @var64
+
+    ; Need this to prevent extension upon load and give a vanilla i8 operand.
+    %val8 = add i8 %val8_tmp, 123
+
+
+; Zero-extending to 32-bits
+    %rhs32_zext = zext i8 %val8 to i32
+    %res32_zext = sub i32 %lhs32, %rhs32_zext
+    store volatile i32 %res32_zext, i32* @var32
+; CHECK: sub {{w[0-9]+}}, {{w[0-9]+}}, {{w[0-9]+}}, uxtb
+
+   %rhs32_zext_shift = shl i32 %rhs32_zext, 3
+   %res32_zext_shift = sub i32 %lhs32, %rhs32_zext_shift
+   store volatile i32 %res32_zext_shift, i32* @var32
+; CHECK: sub {{w[0-9]+}}, {{w[0-9]+}}, {{w[0-9]+}}, uxtb #3
+
+
+; Zero-extending to 64-bits
+    %rhs64_zext = zext i8 %val8 to i64
+    %res64_zext = sub i64 %lhs64, %rhs64_zext
+    store volatile i64 %res64_zext, i64* @var64
+; CHECK: sub {{x[0-9]+}}, {{x[0-9]+}}, {{w[0-9]+}}, uxtb
+
+   %rhs64_zext_shift = shl i64 %rhs64_zext, 1
+   %res64_zext_shift = sub i64 %lhs64, %rhs64_zext_shift
+   store volatile i64 %res64_zext_shift, i64* @var64
+; CHECK: sub {{x[0-9]+}}, {{x[0-9]+}}, {{w[0-9]+}}, uxtb #1
+
+; Sign-extending to 32-bits
+    %rhs32_sext = sext i8 %val8 to i32
+    %res32_sext = sub i32 %lhs32, %rhs32_sext
+    store volatile i32 %res32_sext, i32* @var32
+; CHECK: sub {{w[0-9]+}}, {{w[0-9]+}}, {{w[0-9]+}}, sxtb
+
+   %rhs32_sext_shift = shl i32 %rhs32_sext, 1
+   %res32_sext_shift = sub i32 %lhs32, %rhs32_sext_shift
+   store volatile i32 %res32_sext_shift, i32* @var32
+; CHECK: sub {{w[0-9]+}}, {{w[0-9]+}}, {{w[0-9]+}}, sxtb #1
+
+; Sign-extending to 64-bits
+    %rhs64_sext = sext i8 %val8 to i64
+    %res64_sext = sub i64 %lhs64, %rhs64_sext
+    store volatile i64 %res64_sext, i64* @var64
+; CHECK: sub {{x[0-9]+}}, {{x[0-9]+}}, {{w[0-9]+}}, sxtb
+
+   %rhs64_sext_shift = shl i64 %rhs64_sext, 4
+   %res64_sext_shift = sub i64 %lhs64, %rhs64_sext_shift
+   store volatile i64 %res64_sext_shift, i64* @var64
+; CHECK: sub {{x[0-9]+}}, {{x[0-9]+}}, {{w[0-9]+}}, sxtb #4
+
+    ret void
+}
+
 define void @addsub_i16rhs() minsize {
 ; CHECK-LABEL: addsub_i16rhs:
     %val16_tmp = load i16, i16* @var16
@@ -155,6 +213,64 @@
     ret void
 }
 
+define void @sub_i16rhs() minsize {
+; CHECK-LABEL: sub_i16rhs:
+    %val16_tmp = load i16, i16* @var16
+    %lhs32 = load i32, i32* @var32
+    %lhs64 = load i64, i64* @var64
+
+    ; Need this to prevent extension upon load and give a vanilla i16 operand.
+    %val16 = add i16 %val16_tmp, 123
+
+
+; Zero-extending to 32-bits
+    %rhs32_zext = zext i16 %val16 to i32
+    %res32_zext = sub i32 %lhs32, %rhs32_zext
+    store volatile i32 %res32_zext, i32* @var32
+; CHECK: sub {{w[0-9]+}}, {{w[0-9]+}}, {{w[0-9]+}}, uxth
+
+   %rhs32_zext_shift = shl i32 %rhs32_zext, 3
+   %res32_zext_shift = sub i32 %lhs32, %rhs32_zext_shift
+   store volatile i32 %res32_zext_shift, i32* @var32
+; CHECK: sub {{w[0-9]+}}, {{w[0-9]+}}, {{w[0-9]+}}, uxth #3
+
+
+; Zero-extending to 64-bits
+    %rhs64_zext = zext i16 %val16 to i64
+    %res64_zext = sub i64 %lhs64, %rhs64_zext
+    store volatile i64 %res64_zext, i64* @var64
+; CHECK: sub {{x[0-9]+}}, {{x[0-9]+}}, {{w[0-9]+}}, uxth
+
+   %rhs64_zext_shift = shl i64 %rhs64_zext, 1
+   %res64_zext_shift = sub i64 %lhs64, %rhs64_zext_shift
+   store volatile i64 %res64_zext_shift, i64* @var64
+; CHECK: sub {{x[0-9]+}}, {{x[0-9]+}}, {{w[0-9]+}}, uxth #1
+
+; Sign-extending to 32-bits
+    %rhs32_sext = sext i16 %val16 to i32
+    %res32_sext = sub i32 %lhs32, %rhs32_sext
+    store volatile i32 %res32_sext, i32* @var32
+; CHECK: sub {{w[0-9]+}}, {{w[0-9]+}}, {{w[0-9]+}}, sxth
+
+   %rhs32_sext_shift = shl i32 %rhs32_sext, 1
+   %res32_sext_shift = sub i32 %lhs32, %rhs32_sext_shift
+   store volatile i32 %res32_sext_shift, i32* @var32
+; CHECK: sub {{w[0-9]+}}, {{w[0-9]+}}, {{w[0-9]+}}, sxth #1
+
+; Sign-extending to 64-bits
+    %rhs64_sext = sext i16 %val16 to i64
+    %res64_sext = sub i64 %lhs64, %rhs64_sext
+    store volatile i64 %res64_sext, i64* @var64
+; CHECK: sub {{x[0-9]+}}, {{x[0-9]+}}, {{w[0-9]+}}, sxth
+
+   %rhs64_sext_shift = shl i64 %rhs64_sext, 4
+   %res64_sext_shift = sub i64 %lhs64, %rhs64_sext_shift
+   store volatile i64 %res64_sext_shift, i64* @var64
+; CHECK: sub {{x[0-9]+}}, {{x[0-9]+}}, {{w[0-9]+}}, sxth #4
+
+    ret void
+}
+
 ; N.b. we could probably check more here ("add w2, w3, w1, uxtw" for
 ; example), but the remaining instructions are probably not idiomatic
 ; in the face of "add/sub (shifted register)" so I don't intend to.
@@ -187,3 +303,33 @@
 
     ret void
 }
+
+define void @sub_i32rhs() minsize {
+; CHECK-LABEL: sub_i32rhs:
+    %val32_tmp = load i32, i32* @var32
+    %lhs64 = load i64, i64* @var64
+
+    %val32 = add i32 %val32_tmp, 123
+
+    %rhs64_zext = zext i32 %val32 to i64
+    %res64_zext = sub i64 %lhs64, %rhs64_zext
+    store volatile i64 %res64_zext, i64* @var64
+; CHECK: sub {{x[0-9]+}}, {{x[0-9]+}}, {{w[0-9]+}}, uxtw
+
+    %rhs64_zext_shift = shl i64 %rhs64_zext, 2
+    %res64_zext_shift = sub i64 %lhs64, %rhs64_zext_shift
+    store volatile i64 %res64_zext_shift, i64* @var64
+; CHECK: sub {{x[0-9]+}}, {{x[0-9]+}}, {{w[0-9]+}}, uxtw #2
+
+    %rhs64_sext = sext i32 %val32 to i64
+    %res64_sext = sub i64 %lhs64, %rhs64_sext
+    store volatile i64 %res64_sext, i64* @var64
+; CHECK: sub {{x[0-9]+}}, {{x[0-9]+}}, {{w[0-9]+}}, sxtw
+
+    %rhs64_sext_shift = shl i64 %rhs64_sext, 2
+    %res64_sext_shift = sub i64 %lhs64, %rhs64_sext_shift
+    store volatile i64 %res64_sext_shift, i64* @var64
+; CHECK: sub {{x[0-9]+}}, {{x[0-9]+}}, {{w[0-9]+}}, sxtw #2
+
+    ret void
+}