[llvm] [RISCV] Sink NOT to be fold into ANDN/ORN/XNOR/VANDN (PR #131632)

[Piotr Fusik via llvm-commits]

================
@@ -2109,3 +2109,506 @@ define <vscale x 1 x i16> @vand_vadd_vx_imm16(<vscale x 1 x i16> %x) {
   %b = add <vscale x 1 x i16> %a, splat (i16 32767)
   ret <vscale x 1 x i16> %b
 }
+
+define <vscale x 1 x i8> @vand_vx_hoisted_not(<vscale x 1 x i8> %x, i8 %m, i1 zeroext %cond) {
+; CHECK-LABEL: vand_vx_hoisted_not:
+; CHECK:       # %bb.0:
+; CHECK-NEXT:    beqz a1, .LBB94_2
+; CHECK-NEXT:  # %bb.1: # %mask
+; CHECK-NEXT:    not a0, a0
+; CHECK-NEXT:    vsetvli a1, zero, e8, mf8, ta, ma
+; CHECK-NEXT:    vand.vx v8, v8, a0
+; CHECK-NEXT:  .LBB94_2: # %identity
+; CHECK-NEXT:    ret
+;
+; CHECK-ZVKB-LABEL: vand_vx_hoisted_not:
+; CHECK-ZVKB:       # %bb.0:
+; CHECK-ZVKB-NEXT:    beqz a1, .LBB94_2
+; CHECK-ZVKB-NEXT:  # %bb.1: # %mask
+; CHECK-ZVKB-NEXT:    not a0, a0
+; CHECK-ZVKB-NEXT:    vsetvli a1, zero, e8, mf8, ta, ma
+; CHECK-ZVKB-NEXT:    vand.vx v8, v8, a0
+; CHECK-ZVKB-NEXT:  .LBB94_2: # %identity
+; CHECK-ZVKB-NEXT:    ret
+  %a = xor i8 %m, -1
+  %head = insertelement <vscale x 1 x i8> poison, i8 %a, i32 0
+  %splat = shufflevector <vscale x 1 x i8> %head, <vscale x 1 x i8> poison, <vscale x 1 x i32> zeroinitializer
+  br i1 %cond, label %mask, label %identity
+
+mask:
+  %masked = and <vscale x 1 x i8> %splat, %x
+  ret <vscale x 1 x i8> %masked
+
+identity:
+  ret <vscale x 1 x i8> %x
+}
+
+define <vscale x 1 x i8> @vand_vx_hoisted_not_swapped(<vscale x 1 x i8> %x, i8 %m, i1 zeroext %cond) {
+; CHECK-LABEL: vand_vx_hoisted_not_swapped:
+; CHECK:       # %bb.0:
+; CHECK-NEXT:    beqz a1, .LBB95_2
+; CHECK-NEXT:  # %bb.1: # %mask
+; CHECK-NEXT:    not a0, a0
+; CHECK-NEXT:    vsetvli a1, zero, e8, mf8, ta, ma
+; CHECK-NEXT:    vand.vx v8, v8, a0
+; CHECK-NEXT:  .LBB95_2: # %identity
+; CHECK-NEXT:    ret
+;
+; CHECK-ZVKB-LABEL: vand_vx_hoisted_not_swapped:
+; CHECK-ZVKB:       # %bb.0:
+; CHECK-ZVKB-NEXT:    beqz a1, .LBB95_2
+; CHECK-ZVKB-NEXT:  # %bb.1: # %mask
+; CHECK-ZVKB-NEXT:    not a0, a0
+; CHECK-ZVKB-NEXT:    vsetvli a1, zero, e8, mf8, ta, ma
+; CHECK-ZVKB-NEXT:    vand.vx v8, v8, a0
+; CHECK-ZVKB-NEXT:  .LBB95_2: # %identity
+; CHECK-ZVKB-NEXT:    ret
+  %a = xor i8 %m, -1
+  %head = insertelement <vscale x 1 x i8> poison, i8 %a, i32 0
+  %splat = shufflevector <vscale x 1 x i8> %head, <vscale x 1 x i8> poison, <vscale x 1 x i32> zeroinitializer
+  br i1 %cond, label %mask, label %identity
+
+mask:
+  %masked = and <vscale x 1 x i8> %x, %splat
+  ret <vscale x 1 x i8> %masked
+
+identity:
+  ret <vscale x 1 x i8> %x
+}
+
+define <vscale x 1 x i8> @vand_vv_hoisted_not(<vscale x 1 x i8> %x, <vscale x 1 x i8> %m, i1 zeroext %cond) {
+; CHECK-LABEL: vand_vv_hoisted_not:
+; CHECK:       # %bb.0:
+; CHECK-NEXT:    beqz a0, .LBB96_2
+; CHECK-NEXT:  # %bb.1: # %mask
+; CHECK-NEXT:    vsetvli a0, zero, e8, mf8, ta, ma
+; CHECK-NEXT:    vnot.v v9, v9
+; CHECK-NEXT:    vand.vv v8, v9, v8
+; CHECK-NEXT:  .LBB96_2: # %identity
+; CHECK-NEXT:    ret
+;
+; CHECK-ZVKB-LABEL: vand_vv_hoisted_not:
+; CHECK-ZVKB:       # %bb.0:
+; CHECK-ZVKB-NEXT:    beqz a0, .LBB96_2
+; CHECK-ZVKB-NEXT:  # %bb.1: # %mask
+; CHECK-ZVKB-NEXT:    vsetvli a0, zero, e8, mf8, ta, ma
+; CHECK-ZVKB-NEXT:    vnot.v v9, v9
+; CHECK-ZVKB-NEXT:    vand.vv v8, v9, v8
+; CHECK-ZVKB-NEXT:  .LBB96_2: # %identity
+; CHECK-ZVKB-NEXT:    ret
+  %a = xor <vscale x 1 x i8> %m, splat (i8 -1)
+  br i1 %cond, label %mask, label %identity
+
+mask:
+  %masked = and <vscale x 1 x i8> %a, %x
+  ret <vscale x 1 x i8> %masked
+
+identity:
+  ret <vscale x 1 x i8> %x
+}
+
+define <vscale x 1 x i8> @vand_vv_hoisted_not_swapped(<vscale x 1 x i8> %x, <vscale x 1 x i8> %m, i1 zeroext %cond) {
+; CHECK-LABEL: vand_vv_hoisted_not_swapped:
+; CHECK:       # %bb.0:
+; CHECK-NEXT:    beqz a0, .LBB97_2
+; CHECK-NEXT:  # %bb.1: # %mask
+; CHECK-NEXT:    vsetvli a0, zero, e8, mf8, ta, ma
+; CHECK-NEXT:    vnot.v v9, v9
+; CHECK-NEXT:    vand.vv v8, v8, v9
+; CHECK-NEXT:  .LBB97_2: # %identity
+; CHECK-NEXT:    ret
+;
+; CHECK-ZVKB-LABEL: vand_vv_hoisted_not_swapped:
+; CHECK-ZVKB:       # %bb.0:
+; CHECK-ZVKB-NEXT:    beqz a0, .LBB97_2
+; CHECK-ZVKB-NEXT:  # %bb.1: # %mask
+; CHECK-ZVKB-NEXT:    vsetvli a0, zero, e8, mf8, ta, ma
+; CHECK-ZVKB-NEXT:    vnot.v v9, v9
+; CHECK-ZVKB-NEXT:    vand.vv v8, v8, v9
+; CHECK-ZVKB-NEXT:  .LBB97_2: # %identity
+; CHECK-ZVKB-NEXT:    ret
+  %a = xor <vscale x 1 x i8> %m, splat (i8 -1)
+  br i1 %cond, label %mask, label %identity
+
+mask:
+  %masked = and <vscale x 1 x i8> %x, %a
+  ret <vscale x 1 x i8> %masked
+
+identity:
+  ret <vscale x 1 x i8> %x
+}
+
+declare i64 @llvm.vscale.i64()
+
+define void @vand_vx_loop_hoisted_not(ptr %a, i32 noundef signext %mask) {
----------------
pfusik wrote:

```c
void vand_vx_loop_hoisted_not(int *a, int mask) {
    for (int i = 0; i < 256; i++)
        a[i] &= ~mask;
}
```

https://github.com/llvm/llvm-project/pull/131632