Remove left-shift special case

bytecodealliance · Mar 13, 2023 · ea8077f · ea8077f
1 parent 126a772
commit ea8077f
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Showing 2 changed files with 10 additions and 8 deletions.
diff --git a/cranelift/codegen/src/isa/aarch64/lower.isle b/cranelift/codegen/src/isa/aarch64/lower.isle
@@ -1289,19 +1289,13 @@
           (csel (Cond.Ne) lo_lshift maybe_hi)))))
 
 ;; Shift for vector types.
-(rule -4 (lower (has_type (ty_vec128 ty) (ishl x y)))
+(rule -3 (lower (has_type (ty_vec128 ty) (ishl x y)))
       (let ((size VectorSize (vector_size ty))
             (masked_shift_amt Reg (and_imm $I32 y (shift_mask ty)))
             (shift Reg (vec_dup masked_shift_amt size)))
         (sshl x shift size)))
-(rule -3 (lower (has_type (ty_vec128 ty) (ishl x (iconst (u64_from_imm64 n)))))
-        (ushl_vec_imm x (shift_masked_imm ty n) (vector_size ty)))
-
-;; If left-shifting by zero don't generate a shift instruction and return the
-;; original value
 (rule -2 (lower (has_type (ty_vec128 ty) (ishl x (iconst (u64_from_imm64 n)))))
-        (if-let 0 (shift_masked_imm ty n))
-        x)
+        (ushl_vec_imm x (shift_masked_imm ty n) (vector_size ty)))
 
 (decl pure shift_masked_imm (Type u64) u8)
 (extern constructor shift_masked_imm shift_masked_imm)

diff --git a/cranelift/filetests/filetests/isa/aarch64/simd-arithmetic.clif b/cranelift/filetests/filetests/isa/aarch64/simd-arithmetic.clif
@@ -341,10 +341,12 @@ block0(v0: i8x16):
 
 ; VCode:
 ; block0:
+;   shl v0.16b, v0.16b, #0
 ;   ret
 ; 
 ; Disassembled:
 ; block0: ; offset 0x0
+;   shl v0.16b, v0.16b, #0
 ;   ret
 
 function %ishl_i16x8_full_width(i16x8) -> i16x8 {
@@ -356,10 +358,12 @@ block0(v0: i16x8):
 
 ; VCode:
 ; block0:
+;   shl v0.8h, v0.8h, #0
 ;   ret
 ; 
 ; Disassembled:
 ; block0: ; offset 0x0
+;   shl v0.8h, v0.8h, #0
 ;   ret
 
 function %ishl_i32x4_full_width(i32x4) -> i32x4 {
@@ -371,10 +375,12 @@ block0(v0: i32x4):
 
 ; VCode:
 ; block0:
+;   shl v0.4s, v0.4s, #0
 ;   ret
 ; 
 ; Disassembled:
 ; block0: ; offset 0x0
+;   shl v0.4s, v0.4s, #0
 ;   ret
 
 function %ishl_i64x2_full_width(i64x2) -> i64x2 {
@@ -386,10 +392,12 @@ block0(v0: i64x2):
 
 ; VCode:
 ; block0:
+;   shl v0.2d, v0.2d, #0
 ;   ret
 ; 
 ; Disassembled:
 ; block0: ; offset 0x0
+;   shl v0.2d, v0.2d, #0
 ;   ret
 
 function %sshr_i8x16_full_width(i8x16) -> i8x16 {