x64: add additional select lowerings

cranelift/codegen/src/isa/x64/inst.isle

@@ -779,6 +779,9 @@ src1 src2)
  (ConsumesFlags.ConsumesFlags (MInst.XmmCmove size cc consequent alternative dst)
  (writable_reg_to_reg dst))))
 
+;; TODO Need another version of cmove to handle multiple-register values (i.e.,
+;; I128)
+
 ;; Helper for creating `MInst.MovzxRmR` instructions.
 (decl movzx (Type ExtMode RegMem) Reg)
 (rule (movzx ty mode src)

cranelift/codegen/src/isa/x64/lower.isle

@@ -1161,6 +1161,55 @@
  (value_reg (pminud (put_in_reg x) (put_in_reg_mem y))))
 
 ;;;; Rules for `select` ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+;; CLIF `select` instructions receive a testable argument (i.e. boolean or
+;; integer) that determines which of the other two arguments is selected as
+;; output. Since Cranelift booleans are typically generated by a comparison, the
+;; lowerings in this section "look upwards in the tree" to emit the proper
+;; sequence of "selection" instructions.
+
+(rule (lower (has_type ty (select (def_inst (fcmp (FloatCC.Ordered) a b)) x y)))
+ (value_reg (with_flags_1 (fpcmp ty (put_in_reg_mem a) (put_in_reg b))
+ (cmove ty (CC.NP) (put_in_reg_mem x) (put_in_reg y)))))
+
+(rule (lower (has_type ty (select (def_inst (fcmp (FloatCC.Unordered) a b)) x y)))
+ (value_reg (with_flags_1 (fpcmp ty (put_in_reg_mem a) (put_in_reg b))
+ (cmove ty (CC.P) (put_in_reg_mem x) (put_in_reg y)))))
+
 (rule (lower (has_type ty (select (def_inst (fcmp (FloatCC.GreaterThan) a b)) x y)))
  (value_reg (with_flags_1 (fpcmp ty (put_in_reg_mem a) (put_in_reg b))
  (cmove ty (CC.NBE) (put_in_reg_mem x) (put_in_reg y)))))
+
+(rule (lower (has_type ty (select (def_inst (fcmp (FloatCC.GreaterThanOrEqual) a b)) x y)))
+ (value_reg (with_flags_1 (fpcmp ty (put_in_reg_mem a) (put_in_reg b))
+ (cmove ty (CC.NB) (put_in_reg_mem x) (put_in_reg y)))))
+
+(rule (lower (has_type ty (select (def_inst (fcmp (FloatCC.UnorderedOrLessThan) a b)) x y)))
+ (value_reg (with_flags_1 (fpcmp ty (put_in_reg_mem a) (put_in_reg b))
+ (cmove ty (CC.B) (put_in_reg_mem x) (put_in_reg y)))))
+
+(rule (lower (has_type ty (select (def_inst (fcmp (FloatCC.UnorderedOrLessThanOrEqual) a b)) x y)))
+ (value_reg (with_flags_1 (fpcmp ty (put_in_reg_mem a) (put_in_reg b))
+ (cmove ty (CC.BE) (put_in_reg_mem x) (put_in_reg y)))))
+
+;; Certain FloatCC variants are implemented by flipping the operands of the
+;; comparison (e.g., "greater than" is lowered the same as "less than" but the
+;; comparison is reversed).
+
+(rule (lower (has_type ty (select (def_inst (fcmp (FloatCC.LessThan) a b)) x y)))
+ (value_reg (with_flags_1 (fpcmp ty (put_in_reg_mem b) (put_in_reg a))
+ (cmove ty (CC.NBE) (put_in_reg_mem x) (put_in_reg y)))))
+
+(rule (lower (has_type ty (select (def_inst (fcmp (FloatCC.LessThanOrEqual) a b)) x y)))
+ (value_reg (with_flags_1 (fpcmp ty (put_in_reg_mem b) (put_in_reg a))
+ (cmove ty (CC.NB) (put_in_reg_mem x) (put_in_reg y)))))
+
+(rule (lower (has_type ty (select (def_inst (fcmp (FloatCC.UnorderedOrGreaterThan) a b)) x y)))
+ (value_reg (with_flags_1 (fpcmp ty (put_in_reg_mem b) (put_in_reg a))
+ (cmove ty (CC.B) (put_in_reg_mem x) (put_in_reg y)))))
+
+(rule (lower (has_type ty (select (def_inst (fcmp (FloatCC.UnorderedOrGreaterThanOrEqual) a b)) x y)))
+ (value_reg (with_flags_1 (fpcmp ty (put_in_reg_mem b) (put_in_reg a))
+ (cmove ty (CC.BE) (put_in_reg_mem x) (put_in_reg y)))))
+
+;; TODO `FloatCC.Equal` and `FloatCC.NotEqual` are only implemented with
+;; multiple flag checks (e.g., `CC::P`, `CC::NZ`)

cranelift/codegen/src/isa/x64/lower/isle/generated_code.manifest

@@ -1,4 +1,4 @@
 src/clif.isle f176ef3bba99365
 src/prelude.isle babc931e5dc5b4cf
-src/isa/x64/inst.isle c4ccb93c53d849e1
-src/isa/x64/lower.isle 40f29a8eab1763ce
+src/isa/x64/inst.isle e31f127d75178da6
+src/isa/x64/lower.isle 6e7f2eb81eb7f76