diff --git a/Cargo.lock b/Cargo.lock
index f177b974ab..716f156bfc 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -1989,9 +1989,9 @@ checksum = "fbee7696b84bbf3d89a1c2eccff0850e3047ed46bfcd2e92c29a2d074d57e252"
 
 [[package]]
 name = "souper-ir"
-version = "2.0.0"
+version = "2.1.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "1c7eaed476845a4755001a900e0412dabd356d312ddc35dd32ff91de266b1558"
+checksum = "a50c18ce33988e1973003afbaa66e6a465ad7a614dc33f246879ccc209c2c044"
 dependencies = [
  "id-arena",
 ]
diff --git a/cranelift/codegen/Cargo.toml b/cranelift/codegen/Cargo.toml
index 3f6874778e..cc0a6fd62d 100644
--- a/cranelift/codegen/Cargo.toml
+++ b/cranelift/codegen/Cargo.toml
@@ -29,7 +29,7 @@ peepmatic = { path = "../peepmatic", optional = true, version = "0.68.0" }
 peepmatic-traits = { path = "../peepmatic/crates/traits", optional = true, version = "0.68.0" }
 peepmatic-runtime = { path = "../peepmatic/crates/runtime", optional = true, version = "0.68.0" }
 regalloc = { version = "0.0.31" }
-souper-ir = { version = "2.0.0", optional = true }
+souper-ir = { version = "2.1.0", optional = true }
 wast = { version = "28.0.0", optional = true }
 # It is a goal of the cranelift-codegen crate to have minimal external dependencies.
 # Please don't add any unless they are essential to the task of creating binary
diff --git a/cranelift/codegen/src/souper_harvest.rs b/cranelift/codegen/src/souper_harvest.rs
index 7f8c34d4a2..4884ae5002 100644
--- a/cranelift/codegen/src/souper_harvest.rs
+++ b/cranelift/codegen/src/souper_harvest.rs
@@ -392,6 +392,28 @@ fn harvest_candidate_lhs(
                     }
                     (ir::Opcode::Select, _) => {
                         let a = arg(allocs, 0);
+
+                        // While Cranelift allows any width condition for
+                        // `select`, Souper requires an `i1`.
+                        let a = match a {
+                            ast::Operand::Value(id) => match lhs.get_value(id).r#type {
+                                Some(ast::Type { width: 1 }) => a,
+                                _ => lhs
+                                    .assignment(
+                                        None,
+                                        Some(ast::Type { width: 1 }),
+                                        ast::Instruction::Trunc { a },
+                                        vec![],
+                                    )
+                                    .into(),
+                            },
+                            ast::Operand::Constant(ast::Constant { value, .. }) => ast::Constant {
+                                value: (value != 0) as _,
+                                r#type: Some(ast::Type { width: 1 }),
+                            }
+                            .into(),
+                        };
+
                         let b = arg(allocs, 1);
                         let c = arg(allocs, 2);
                         ast::Instruction::Select { a, b, c }.into()
diff --git a/cranelift/peepmatic/crates/souper/Cargo.toml b/cranelift/peepmatic/crates/souper/Cargo.toml
index e5717ecea8..84bf6f52e0 100644
--- a/cranelift/peepmatic/crates/souper/Cargo.toml
+++ b/cranelift/peepmatic/crates/souper/Cargo.toml
@@ -10,7 +10,7 @@ description = "Converting Souper optimizations into Peepmatic DSL"
 
 [dependencies]
 anyhow = "1"
-souper-ir = { version = "2.0.0", features = ["parse"] }
+souper-ir = { version = "2.1.0", features = ["parse"] }
 log = "0.4.8"
 
 [dev-dependencies]