diff --git a/cranelift/codegen/src/isa/x64/lower.isle b/cranelift/codegen/src/isa/x64/lower.isle
index d082fda8ef5e..cb7636939d6f 100644
--- a/cranelift/codegen/src/isa/x64/lower.isle
+++ b/cranelift/codegen/src/isa/x64/lower.isle
@@ -1894,34 +1894,34 @@
 ;; keep these here than write an external extractor containing bits of
 ;; the instruction pattern.s)
 (rule (lower (has_type $I64
-                       (uextend src @ (iadd _ _))))
+                       (uextend src @ (has_type $I32 (iadd _ _)))))
       src)
 (rule (lower (has_type $I64
-                       (uextend src @ (iadd_ifcout _ _))))
+                       (uextend src @ (has_type $I32 (iadd_ifcout _ _)))))
       src)
 (rule (lower (has_type $I64
-                       (uextend src @ (isub _ _))))
+                       (uextend src @ (has_type $I32 (isub _ _)))))
       src)
 (rule (lower (has_type $I64
-                       (uextend src @ (imul _ _))))
+                       (uextend src @ (has_type $I32 (imul _ _)))))
       src)
 (rule (lower (has_type $I64
-                       (uextend src @ (band _ _))))
+                       (uextend src @ (has_type $I32 (band _ _)))))
       src)
 (rule (lower (has_type $I64
-                       (uextend src @ (bor _ _))))
+                       (uextend src @ (has_type $I32 (bor _ _)))))
       src)
 (rule (lower (has_type $I64
-                       (uextend src @ (bxor _ _))))
+                       (uextend src @ (has_type $I32 (bxor _ _)))))
       src)
 (rule (lower (has_type $I64
-                       (uextend src @ (ishl _ _))))
+                       (uextend src @ (has_type $I32 (ishl _ _)))))
       src)
 (rule (lower (has_type $I64
-                       (uextend src @ (ushr _ _))))
+                       (uextend src @ (has_type $I32 (ushr _ _)))))
       src)
 (rule (lower (has_type $I64
-                       (uextend src @ (uload32 _ _ _))))
+                       (uextend src @ (has_type $I32 (uload32 _ _ _)))))
       src)
 
 ;; Rules for `sextend` / `bextend` ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
diff --git a/cranelift/codegen/src/isa/x64/lower/isle/generated_code.manifest b/cranelift/codegen/src/isa/x64/lower/isle/generated_code.manifest
index b1f03e50d893..ebb1176c915f 100644
--- a/cranelift/codegen/src/isa/x64/lower/isle/generated_code.manifest
+++ b/cranelift/codegen/src/isa/x64/lower/isle/generated_code.manifest
@@ -1,4 +1,4 @@
 src/clif.isle 9ea75a6f790b5c03
 src/prelude.isle b2bc986bcbbbb77
 src/isa/x64/inst.isle 40f495d3ca5ae547
-src/isa/x64/lower.isle faa2a07bba48a813
+src/isa/x64/lower.isle c049f7d36db0e0fb
diff --git a/cranelift/codegen/src/isa/x64/lower/isle/generated_code.rs b/cranelift/codegen/src/isa/x64/lower/isle/generated_code.rs
index b409fad5c4b3..ab52c9cadd61 100644
--- a/cranelift/codegen/src/isa/x64/lower/isle/generated_code.rs
+++ b/cranelift/codegen/src/isa/x64/lower/isle/generated_code.rs
@@ -4665,101 +4665,107 @@ pub fn constructor_lower<C: Context>(ctx: &mut C, arg0: Inst) -> Option<InstOutp
                     }
                     &Opcode::Uextend => {
                         if let Some(pattern7_0) = C::def_inst(ctx, pattern5_1) {
-                            let pattern8_0 = C::inst_data(ctx, pattern7_0);
-                            match &pattern8_0 {
-                                &InstructionData::Binary {
-                                    opcode: ref pattern9_0,
-                                    args: ref pattern9_1,
-                                } => {
-                                    match pattern9_0 {
-                                        &Opcode::Iadd => {
-                                            let (pattern11_0, pattern11_1) =
-                                                C::unpack_value_array_2(ctx, pattern9_1);
-                                            // Rule at src/isa/x64/lower.isle line 1896.
-                                            let expr0_0 =
-                                                constructor_output_value(ctx, pattern5_1)?;
-                                            return Some(expr0_0);
-                                        }
-                                        &Opcode::Isub => {
-                                            let (pattern11_0, pattern11_1) =
-                                                C::unpack_value_array_2(ctx, pattern9_1);
-                                            // Rule at src/isa/x64/lower.isle line 1902.
-                                            let expr0_0 =
-                                                constructor_output_value(ctx, pattern5_1)?;
-                                            return Some(expr0_0);
-                                        }
-                                        &Opcode::Imul => {
-                                            let (pattern11_0, pattern11_1) =
-                                                C::unpack_value_array_2(ctx, pattern9_1);
-                                            // Rule at src/isa/x64/lower.isle line 1905.
-                                            let expr0_0 =
-                                                constructor_output_value(ctx, pattern5_1)?;
-                                            return Some(expr0_0);
-                                        }
-                                        &Opcode::IaddIfcout => {
-                                            let (pattern11_0, pattern11_1) =
-                                                C::unpack_value_array_2(ctx, pattern9_1);
-                                            // Rule at src/isa/x64/lower.isle line 1899.
-                                            let expr0_0 =
-                                                constructor_output_value(ctx, pattern5_1)?;
-                                            return Some(expr0_0);
-                                        }
-                                        &Opcode::Band => {
-                                            let (pattern11_0, pattern11_1) =
-                                                C::unpack_value_array_2(ctx, pattern9_1);
-                                            // Rule at src/isa/x64/lower.isle line 1908.
-                                            let expr0_0 =
-                                                constructor_output_value(ctx, pattern5_1)?;
-                                            return Some(expr0_0);
-                                        }
-                                        &Opcode::Bor => {
-                                            let (pattern11_0, pattern11_1) =
-                                                C::unpack_value_array_2(ctx, pattern9_1);
-                                            // Rule at src/isa/x64/lower.isle line 1911.
-                                            let expr0_0 =
-                                                constructor_output_value(ctx, pattern5_1)?;
-                                            return Some(expr0_0);
-                                        }
-                                        &Opcode::Bxor => {
-                                            let (pattern11_0, pattern11_1) =
-                                                C::unpack_value_array_2(ctx, pattern9_1);
-                                            // Rule at src/isa/x64/lower.isle line 1914.
-                                            let expr0_0 =
-                                                constructor_output_value(ctx, pattern5_1)?;
-                                            return Some(expr0_0);
-                                        }
-                                        &Opcode::Ishl => {
-                                            let (pattern11_0, pattern11_1) =
-                                                C::unpack_value_array_2(ctx, pattern9_1);
-                                            // Rule at src/isa/x64/lower.isle line 1917.
-                                            let expr0_0 =
-                                                constructor_output_value(ctx, pattern5_1)?;
-                                            return Some(expr0_0);
+                            if let Some(pattern8_0) = C::first_result(ctx, pattern7_0) {
+                                let pattern9_0 = C::value_type(ctx, pattern8_0);
+                                if pattern9_0 == I32 {
+                                    let pattern11_0 = C::inst_data(ctx, pattern7_0);
+                                    match &pattern11_0 {
+                                        &InstructionData::Binary {
+                                            opcode: ref pattern12_0,
+                                            args: ref pattern12_1,
+                                        } => {
+                                            match pattern12_0 {
+                                                &Opcode::Iadd => {
+                                                    let (pattern14_0, pattern14_1) =
+                                                        C::unpack_value_array_2(ctx, pattern12_1);
+                                                    // Rule at src/isa/x64/lower.isle line 1896.
+                                                    let expr0_0 =
+                                                        constructor_output_value(ctx, pattern5_1)?;
+                                                    return Some(expr0_0);
+                                                }
+                                                &Opcode::Isub => {
+                                                    let (pattern14_0, pattern14_1) =
+                                                        C::unpack_value_array_2(ctx, pattern12_1);
+                                                    // Rule at src/isa/x64/lower.isle line 1902.
+                                                    let expr0_0 =
+                                                        constructor_output_value(ctx, pattern5_1)?;
+                                                    return Some(expr0_0);
+                                                }
+                                                &Opcode::Imul => {
+                                                    let (pattern14_0, pattern14_1) =
+                                                        C::unpack_value_array_2(ctx, pattern12_1);
+                                                    // Rule at src/isa/x64/lower.isle line 1905.
+                                                    let expr0_0 =
+                                                        constructor_output_value(ctx, pattern5_1)?;
+                                                    return Some(expr0_0);
+                                                }
+                                                &Opcode::IaddIfcout => {
+                                                    let (pattern14_0, pattern14_1) =
+                                                        C::unpack_value_array_2(ctx, pattern12_1);
+                                                    // Rule at src/isa/x64/lower.isle line 1899.
+                                                    let expr0_0 =
+                                                        constructor_output_value(ctx, pattern5_1)?;
+                                                    return Some(expr0_0);
+                                                }
+                                                &Opcode::Band => {
+                                                    let (pattern14_0, pattern14_1) =
+                                                        C::unpack_value_array_2(ctx, pattern12_1);
+                                                    // Rule at src/isa/x64/lower.isle line 1908.
+                                                    let expr0_0 =
+                                                        constructor_output_value(ctx, pattern5_1)?;
+                                                    return Some(expr0_0);
+                                                }
+                                                &Opcode::Bor => {
+                                                    let (pattern14_0, pattern14_1) =
+                                                        C::unpack_value_array_2(ctx, pattern12_1);
+                                                    // Rule at src/isa/x64/lower.isle line 1911.
+                                                    let expr0_0 =
+                                                        constructor_output_value(ctx, pattern5_1)?;
+                                                    return Some(expr0_0);
+                                                }
+                                                &Opcode::Bxor => {
+                                                    let (pattern14_0, pattern14_1) =
+                                                        C::unpack_value_array_2(ctx, pattern12_1);
+                                                    // Rule at src/isa/x64/lower.isle line 1914.
+                                                    let expr0_0 =
+                                                        constructor_output_value(ctx, pattern5_1)?;
+                                                    return Some(expr0_0);
+                                                }
+                                                &Opcode::Ishl => {
+                                                    let (pattern14_0, pattern14_1) =
+                                                        C::unpack_value_array_2(ctx, pattern12_1);
+                                                    // Rule at src/isa/x64/lower.isle line 1917.
+                                                    let expr0_0 =
+                                                        constructor_output_value(ctx, pattern5_1)?;
+                                                    return Some(expr0_0);
+                                                }
+                                                &Opcode::Ushr => {
+                                                    let (pattern14_0, pattern14_1) =
+                                                        C::unpack_value_array_2(ctx, pattern12_1);
+                                                    // Rule at src/isa/x64/lower.isle line 1920.
+                                                    let expr0_0 =
+                                                        constructor_output_value(ctx, pattern5_1)?;
+                                                    return Some(expr0_0);
+                                                }
+                                                _ => {}
+                                            }
                                         }
-                                        &Opcode::Ushr => {
-                                            let (pattern11_0, pattern11_1) =
-                                                C::unpack_value_array_2(ctx, pattern9_1);
-                                            // Rule at src/isa/x64/lower.isle line 1920.
-                                            let expr0_0 =
-                                                constructor_output_value(ctx, pattern5_1)?;
-                                            return Some(expr0_0);
+                                        &InstructionData::Load {
+                                            opcode: ref pattern12_0,
+                                            arg: pattern12_1,
+                                            flags: pattern12_2,
+                                            offset: pattern12_3,
+                                        } => {
+                                            if let &Opcode::Uload32 = pattern12_0 {
+                                                // Rule at src/isa/x64/lower.isle line 1923.
+                                                let expr0_0 =
+                                                    constructor_output_value(ctx, pattern5_1)?;
+                                                return Some(expr0_0);
+                                            }
                                         }
                                         _ => {}
                                     }
                                 }
-                                &InstructionData::Load {
-                                    opcode: ref pattern9_0,
-                                    arg: pattern9_1,
-                                    flags: pattern9_2,
-                                    offset: pattern9_3,
-                                } => {
-                                    if let &Opcode::Uload32 = pattern9_0 {
-                                        // Rule at src/isa/x64/lower.isle line 1923.
-                                        let expr0_0 = constructor_output_value(ctx, pattern5_1)?;
-                                        return Some(expr0_0);
-                                    }
-                                }
-                                _ => {}
                             }
                         }
                         let pattern7_0 = C::value_type(ctx, pattern5_1);
diff --git a/cranelift/filetests/filetests/runtests/extend.clif b/cranelift/filetests/filetests/runtests/extend.clif
index 524177de1054..42e77f7f0bb6 100644
--- a/cranelift/filetests/filetests/runtests/extend.clif
+++ b/cranelift/filetests/filetests/runtests/extend.clif
@@ -1,23 +1,213 @@
 test run
 target aarch64
-target arm
 target s390x
 target x86_64
 
-function %uextend() -> b1 {
-block0:
-    v0 = iconst.i32 0xffff_ee00
+;;;; basic uextend
+
+function %uextend8_16(i8) -> i16 {
+block0(v0: i8):
+    v1 = uextend.i16 v0
+    return v1
+}
+; run: %uextend8_16(0xfe) == 0xfe
+; run: %uextend8_16(0x7e) == 0x7e
+
+function %uextend8_32(i8) -> i32 {
+block0(v0: i8):
+    v1 = uextend.i32 v0
+    return v1
+}
+; run: %uextend8_32(0xfe) == 0xfe
+; run: %uextend8_32(0x7e) == 0x7e
+
+function %uextend16_32(i16) -> i32 {
+block0(v0: i16):
+    v1 = uextend.i32 v0
+    return v1
+}
+; run: %uextend16_32(0xfe00) == 0xfe00
+; run: %uextend16_32(0x7e00) == 0x7e00
+
+function %uextend8_64(i8) -> i64 {
+block0(v0: i8):
     v1 = uextend.i64 v0
-    v2 = icmp_imm eq v1, 0xffff_ee00
-    return v2
+    return v1
 }
-; run
+; run: %uextend8_64(0xfe) == 0xfe
+; run: %uextend8_64(0x7e) == 0x7e
+
+function %uextend16_64(i16) -> i64 {
+block0(v0: i16):
+    v1 = uextend.i64 v0
+    return v1
+}
+; run: %uextend16_64(0xfe00) == 0xfe00
+; run: %uextend16_64(0x7e00) == 0x7e00
+
+function %uextend32_64(i32) -> i64 {
+block0(v0: i32):
+    v1 = uextend.i64 v0
+    return v1
+}
+; run: %uextend32_64(0xffff_ee00) == 0xffff_ee00
+; run: %uextend32_64(0x7fff_ee00) == 0x7fff_ee00
+
+;;;; basic sextend
 
-function %sextend() -> b1 {
-block0:
-    v0 = iconst.i32 0xffff_ee00
+function %sextend8_16(i8) -> i16 {
+block0(v0: i8):
+    v1 = sextend.i16 v0
+    return v1
+}
+; run: %sextend8_16(0xff) == 0xffff
+; run: %sextend8_16(0x7f) == 0x7f
+
+function %sextend8_32(i8) -> i32 {
+block0(v0: i8):
+    v1 = sextend.i32 v0
+    return v1
+}
+; run: %sextend8_32(0xff) == 0xffff_ffff
+; run: %sextend8_32(0x7f) == 0x7f
+
+function %sextend16_32(i16) -> i32 {
+block0(v0: i16):
+    v1 = sextend.i32 v0
+    return v1
+}
+; run: %sextend16_32(0xfe00) == 0xffff_fe00
+; run: %sextend16_32(0x7e00) == 0x7e00
+
+function %sextend8_64(i8) -> i64 {
+block0(v0: i8):
     v1 = sextend.i64 v0
-    v2 = icmp_imm eq v1, 0xffff_ffff_ffff_ee00
-    return v2
+    return v1
 }
-; run
+; run: %sextend8_64(0xff) == 0xffff_ffff_ffff_ffff
+; run: %sextend8_64(0x7f) == 0x7f
+
+function %sextend16_64(i16) -> i64 {
+block0(v0: i16):
+    v1 = sextend.i64 v0
+    return v1
+}
+; run: %sextend16_64(0xfe00) == 0xffff_ffff_ffff_fe00
+; run: %sextend16_64(0x7e00) == 0x7e00
+
+function %sextend32_64(i32) -> i64 {
+block0(v0: i32):
+    v1 = sextend.i64 v0
+    return v1
+}
+; run: %sextend32_64(0xffff_ee00) == 0xffff_ffff_ffff_ee00
+; run: %sextend32_64(0x7fff_ee00) == 0x7fff_ee00
+
+;; uextend of an `add` that we know is likely to set undefined bits
+;; above the narrow value
+
+function %add_uextend8_16(i8, i8) -> i16 {
+block0(v0: i8, v1: i8):
+    v2 = iadd.i8 v0, v1
+    v3 = uextend.i16 v2
+    return v3
+}
+; run: %add_uextend8_16(0xfe, 0x03) == 0x0001
+
+function %add_uextend8_32(i8, i8) -> i32 {
+block0(v0: i8, v1: i8):
+    v2 = iadd.i8 v0, v1
+    v3 = uextend.i32 v2
+    return v3
+}
+; run: %add_uextend8_32(0xfe, 0x03) == 0x0000_0001
+
+function %add_uextend16_32(i16, i16) -> i32 {
+block0(v0: i16, v1: i16):
+    v2 = iadd.i16 v0, v1
+    v3 = uextend.i32 v2
+    return v3
+}
+; run: %add_uextend16_32(0xfe00, 0x302) == 0x0000_0102
+
+function %add_uextend8_64(i8, i8) -> i64 {
+block0(v0: i8, v1: i8):
+    v2 = iadd.i8 v0, v1
+    v3 = uextend.i64 v2
+    return v3
+}
+; run: %add_uextend8_64(0xfe, 0x03) == 0x0000_0000_0000_0001
+
+function %add_uextend16_64(i16, i16) -> i64 {
+block0(v0: i16, v1: i16):
+    v2 = iadd.i16 v0, v1
+    v3 = uextend.i64 v2
+    return v3
+}
+; run: %add_uextend16_64(0xfe00, 0x302) == 0x0000_0000_0000_0102
+
+function %add_uextend32_64(i32, i32) -> i64 {
+block0(v0: i32, v1: i32):
+    v2 = iadd.i32 v0, v1
+    v3 = uextend.i64 v2
+    return v3
+}
+; run: %add_uextend32_64(0xffff_ee00, 0x1000_0001) == 0x0000_0000_0fff_ee01
+
+;; sextend of an `add` that we know is likely to set undefined bits
+;; above the narrow value
+
+function %add_sextend8_16(i8, i8) -> i16 {
+block0(v0: i8, v1: i8):
+    v2 = iadd.i8 v0, v1
+    v3 = sextend.i16 v2
+    return v3
+}
+; run: %add_sextend8_16(0xfe, 0x03) == 0x0001
+; run: %add_sextend8_16(0xfe, 0x83) == 0xff81
+
+function %add_sextend8_32(i8, i8) -> i32 {
+block0(v0: i8, v1: i8):
+    v2 = iadd.i8 v0, v1
+    v3 = sextend.i32 v2
+    return v3
+}
+; run: %add_sextend8_32(0xfe, 0x03) == 0x0000_0001
+; run: %add_sextend8_32(0xfe, 0x83) == 0xffff_ff81
+
+function %add_sextend16_32(i16, i16) -> i32 {
+block0(v0: i16, v1: i16):
+    v2 = iadd.i16 v0, v1
+    v3 = sextend.i32 v2
+    return v3
+}
+; run: %add_sextend16_32(0xfe00, 0x302) == 0x0000_0102
+; run: %add_sextend16_32(0xfe00, 0x8302) == 0xffff_8102
+
+function %add_sextend8_64(i8, i8) -> i64 {
+block0(v0: i8, v1: i8):
+    v2 = iadd.i8 v0, v1
+    v3 = sextend.i64 v2
+    return v3
+}
+; run: %add_sextend8_64(0xfe, 0x03) == 0x0000_0000_0000_0001
+; run: %add_sextend8_64(0xfe, 0x83) == 0xffff_ffff_ffff_ff81
+
+function %add_sextend16_64(i16, i16) -> i64 {
+block0(v0: i16, v1: i16):
+    v2 = iadd.i16 v0, v1
+    v3 = sextend.i64 v2
+    return v3
+}
+; run: %add_sextend16_64(0xfe00, 0x302) == 0x0000_0000_0000_0102
+; run: %add_sextend16_64(0xfe00, 0x8302) == 0xffff_ffff_ffff_8102
+
+function %add_sextend32_64(i32, i32) -> i64 {
+block0(v0: i32, v1: i32):
+    v2 = iadd.i32 v0, v1
+    v3 = sextend.i64 v2
+    return v3
+}
+; run: %add_sextend32_64(0xffff_ee00, 0x1000_0001) == 0x0000_0000_0fff_ee01
+; run: %add_sextend32_64(0xffff_ee00, 0x9000_0001) == 0xffff_ffff_8fff_ee01
+