[NFC][AARCH64] Add test cases for negation of select

[sunho]

Summary

Add tests to demonstrate new dag combine pattern.

[dmgreen]

LGTM. Cheers

llvm/test/CodeGen/AArch64/neg-selects.ll

+; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py
+; RUN: llc -mtriple=aarch64-none-none-eabi %s -o - | FileCheck %s
+
+define i32 @neg_select_neg(i32 %a, i32 %b, i1 %bb) {
+; CHECK-LABEL: neg_select_neg:
+; CHECK:       // %bb.0:
+; CHECK-NEXT:    tst w2, #0x1
+; CHECK-NEXT:    csel w0, w0, w1, ne
+; CHECK-NEXT:    ret
+  %nega = sub i32 0, %a
+  %negb = sub i32 0, %b
+  %sel = select i1 %bb, i32 %nega, i32 %negb
+  %res = sub i32 0, %sel
+  ret i32 %res
+}
+
+define i32 @negneg_select_nega(i32 %a, i32 %b, i1 %bb) {
+; CHECK-LABEL: negneg_select_nega:
+; CHECK:       // %bb.0:
+; CHECK-NEXT:    tst w2, #0x1
+; CHECK-NEXT:    csneg w0, w1, w0, eq
+; CHECK-NEXT:    ret
+  %nega = sub i32 0, %a
+  %sel = select i1 %bb, i32 %nega, i32 %b
+  %nsel = sub i32 0, %sel
+  %res = sub i32 0, %nsel
+  ret i32 %res
+}
+
+define i32 @neg_select_nega(i32 %a, i32 %b, i1 %bb) {
+; CHECK-LABEL: neg_select_nega:
+; CHECK:       // %bb.0:
+; CHECK-NEXT:    tst w2, #0x1
+; CHECK-NEXT:    csneg w8, w1, w0, eq
+; CHECK-NEXT:    neg w0, w8
+; CHECK-NEXT:    ret
+  %nega = sub i32 0, %a
+  %sel = select i1 %bb, i32 %nega, i32 %b
+  %res = sub i32 0, %sel
+  ret i32 %res
+}
+
+define i32 @neg_select_negb(i32 %a, i32 %b, i1 %bb) {
+; CHECK-LABEL: neg_select_negb:
+; CHECK:       // %bb.0:
+; CHECK-NEXT:    tst w2, #0x1
+; CHECK-NEXT:    csneg w8, w0, w1, ne
+; CHECK-NEXT:    neg w0, w8
+; CHECK-NEXT:    ret
+  %negb = sub i32 0, %b
+  %sel = select i1 %bb, i32 %a, i32 %negb
+  %res = sub i32 0, %sel
+  ret i32 %res
+}
+
+define i32 @neg_select_ab(i32 %a, i32 %b, i1 %bb) {
+; CHECK-LABEL: neg_select_ab:
+; CHECK:       // %bb.0:
+; CHECK-NEXT:    tst w2, #0x1
+; CHECK-NEXT:    csel w8, w0, w1, ne
+; CHECK-NEXT:    neg w0, w8
+; CHECK-NEXT:    ret
+  %sel = select i1 %bb, i32 %a, i32 %b
+  %res = sub i32 0, %sel
+  ret i32 %res
+}
+
+define i32 @neg_select_nega_with_use(i32 %a, i32 %b, i1 %bb) {
+; CHECK-LABEL: neg_select_nega_with_use:
+; CHECK:       // %bb.0:
+; CHECK-NEXT:    tst w2, #0x1
+; CHECK-NEXT:    neg w8, w0
+; CHECK-NEXT:    csneg w9, w1, w0, eq
+; CHECK-NEXT:    sub w0, w8, w9
+; CHECK-NEXT:    ret
+  %nega = sub i32 0, %a
+  %sel = select i1 %bb, i32 %nega, i32 %b
+  %nsel = sub i32 0, %sel
+  %res = add i32 %nsel, %nega
+  ret i32 %res
+}