cranelift: Implement icmp for scalar types

Add `icmp` tests for all scalar types and condition codes.

AArch64 (no)overflow tests are disabled because they are currently failing.

cranelift/filetests/filetests/runtests/icmp-of.clif

@@ -0,0 +1,75 @@
+test interpret
+test run
+target x86_64 machinst
+
+function %icmp_of_i8(i8, i8) -> b1 {
+block0(v0: i8, v1: i8):
+    v2 = icmp of v0, v1
+    return v2
+}
+; run: %icmp_of_i8(0, 0) == false
+; run: %icmp_of_i8(0, 1) == false
+; run: %icmp_of_i8(1, 0) == false
+; run: %icmp_of_i8(0, -1) == false
+; run: %icmp_of_i8(0x80, 0x80) == false
+; run: %icmp_of_i8(0x7F, 1) == false
+; run: %icmp_of_i8(0x7F, 0x7F) == false
+; run: %icmp_of_i8(0xFF, 1) == false
+; run: %icmp_of_i8(0x80, 1) == true
+; run: %icmp_of_i8(0x7F, 0x80) == true
+; run: %icmp_of_i8(0x80, 0x7F) == true
+; run: %icmp_of_i8(0x7F, 0xFF) == true
+
+function %icmp_of_i16(i16, i16) -> b1 {
+block0(v0: i16, v1: i16):
+    v2 = icmp of v0, v1
+    return v2
+}
+; run: %icmp_of_i16(0, 0) == false
+; run: %icmp_of_i16(0, 1) == false
+; run: %icmp_of_i16(1, 0) == false
+; run: %icmp_of_i16(0, -1) == false
+; run: %icmp_of_i16(0x8000, 0x8000) == false
+; run: %icmp_of_i16(0x7FFF, 1) == false
+; run: %icmp_of_i16(0x7FFF, 0x7FFF) == false
+; run: %icmp_of_i16(0xFFFF, 1) == false
+; run: %icmp_of_i16(0x8000, 1) == true
+; run: %icmp_of_i16(0x7FFF, 0x8000) == true
+; run: %icmp_of_i16(0x8000, 0x7FFF) == true
+; run: %icmp_of_i16(0x7FFF, 0xFFFF) == true
+
+function %icmp_of_i32(i32, i32) -> b1 {
+block0(v0: i32, v1: i32):
+    v2 = icmp of v0, v1
+    return v2
+}
+; run: %icmp_of_i32(0, 0) == false
+; run: %icmp_of_i32(0, 1) == false
+; run: %icmp_of_i32(1, 0) == false
+; run: %icmp_of_i32(0, -1) == false
+; run: %icmp_of_i32(0x80000000, 0x80000000) == false
+; run: %icmp_of_i32(0x7FFFFFFF, 1) == false
+; run: %icmp_of_i32(0x7FFFFFFF, 0x7FFFFFFF) == false
+; run: %icmp_of_i32(0xFFFFFFFF, 1) == false
+; run: %icmp_of_i32(0x80000000, 1) == true
+; run: %icmp_of_i32(0x7FFFFFFF, 0x80000000) == true
+; run: %icmp_of_i32(0x80000000, 0x7FFFFFFF) == true
+; run: %icmp_of_i32(0x7FFFFFFF, 0xFFFFFFFF) == true
+
+function %icmp_of_i64(i64, i64) -> b1 {
+block0(v0: i64, v1: i64):
+    v2 = icmp of v0, v1
+    return v2
+}
+; run: %icmp_of_i64(0, 0) == false
+; run: %icmp_of_i64(0, 1) == false
+; run: %icmp_of_i64(1, 0) == false
+; run: %icmp_of_i64(0, -1) == false
+; run: %icmp_of_i64(0x80000000_00000000, 0x80000000_00000000) == false
+; run: %icmp_of_i64(0x7FFFFFFF_FFFFFFFF, 1) == false
+; run: %icmp_of_i64(0x7FFFFFFF_FFFFFFFF, 0x7FFFFFFF_FFFFFFFF) == false
+; run: %icmp_of_i64(0xFFFFFFFF_FFFFFFFF, 1) == false
+; run: %icmp_of_i64(0x80000000_00000000, 1) == true
+; run: %icmp_of_i64(0x7FFFFFFF_FFFFFFFF, 0x80000000_00000000) == true
+; run: %icmp_of_i64(0x80000000_00000000, 0x7FFFFFFF_FFFFFFFF) == true
+; run: %icmp_of_i64(0x7FFFFFFF_FFFFFFFF, 0xFFFFFFFF_FFFFFFFF) == true