s390x: Emit instructions for bitwise FP ops

cranelift requires that bitwise operations work across all
data types, including floating point. The prior implementation
of bitwise operations, xor in this example, would cause a panic
 with the message:
    no rule matched for term aluop_xor

This patch adds lowerings for bitwise operations on floating
point registers using the vector instructions and the vector
register overlay property of the s390x register file.

Author: theotherjimmy

cranelift/codegen/src/isa/s390x/lower.isle

@@ -997,6 +997,10 @@
 (rule (lower (has_type (vr128_ty ty) (bnot x)))
       (vec_not ty x))
 
+;; Float version using vector NOR.
+(rule 5 (lower (has_type (ty_scalar_float _) (bnot x)))
+      (vec_not $F64X2 x))
+
 ;; With z15 (bnot (bxor ...)) can be a single instruction, similar to the
 ;; (bxor _ (bnot _)) lowering.
 (rule 3 (lower (has_type (and (mie3_enabled) (fits_in_64 ty)) (bnot (bxor x y))))
@@ -1033,6 +1037,10 @@
 (rule 0 (lower (has_type (vr128_ty ty) (band x y)))
       (vec_and ty x y))
 
+;; And two float registers, using vector overlay.
+(rule 11 (lower (has_type (ty_scalar_float _) (band x y)))
+      (vec_and $F64X2 x y))
+
 ;; Specialized lowerings for `(band x (bnot y))` which is additionally produced
 ;; by Cranelift's `band_not` instruction that is legalized into the simpler
 ;; forms early on.
@@ -1075,6 +1083,10 @@
 (rule 0 (lower (has_type (vr128_ty ty) (bor x y)))
       (vec_or ty x y))
 
+;; Or two floating registers, using vector overlay
+(rule 11 (lower (has_type (ty_scalar_float _) (bor x y)))
+      (vec_or $F64X2 x y))
+
 ;; Specialized lowerings for `(bor x (bnot y))` which is additionally produced
 ;; by Cranelift's `bor_not` instruction that is legalized into the simpler
 ;; forms early on.
@@ -1114,6 +1126,10 @@
 (rule 0 (lower (has_type (vr128_ty ty) (bxor x y)))
       (vec_xor ty x y))
 
+;; Xor two floating registers, using vector overlay
+(rule 9 (lower (has_type (ty_scalar_float _) (bxor x y)))
+      (vec_xor $F64X2 x y))
+
 ;; Specialized lowerings for `(bxor x (bnot y))` which is additionally produced
 ;; by Cranelift's `bxor_not` instruction that is legalized into the simpler
 ;; forms early on.

cranelift/filetests/filetests/isa/s390x/bitwise.clif

@@ -1076,3 +1076,67 @@ block0(v0: i32x4, v1: i32x4):
 ;   vnx %v24, %v24, %v25
 ;   br %r14
 
+function %bnot_f64(f64) -> f64 {
+block0(v0: f64):
+  v1 = bnot v0
+  return  v1
+}
+
+; VCode:
+; block0:
+;   vno %v0, %v0, %v0
+;   br %r14
+;
+; Disassembled:
+; block0: ; offset 0x0
+;   vno %v0, %v0, %v0
+;   br %r14
+
+function %band_f64(f64, f64) -> f64 {
+block0(v0: f64, v1: f64):
+  v2 = band v0, v1
+  return  v2
+}
+
+; VCode:
+; block0:
+;   vn %v0, %v0, %v2
+;   br %r14
+;
+; Disassembled:
+; block0: ; offset 0x0
+;   vn %v0, %v0, %v2
+;   br %r14
+
+function %bor_f64(f64, f64) -> f64 {
+block0(v0: f64, v1: f64):
+  v2 = bor v0, v1
+  return  v2
+}
+
+; VCode:
+; block0:
+;   vo %v0, %v0, %v2
+;   br %r14
+;
+; Disassembled:
+; block0: ; offset 0x0
+;   vo %v0, %v0, %v2
+;   br %r14
+
+function %bxor_f64(f64, f64) -> f64 {
+block0(v0: f64, v1: f64):
+  v2 = bxor v0, v1
+  return  v2
+}
+
+; VCode:
+; block0:
+;   vx %v0, %v0, %v2
+;   br %r14
+;
+; Disassembled:
+; block0: ; offset 0x0
+;   vx %v0, %v0, %v2
+;   br %r14
+