[InstSimplify] add tests for expandCommutativeBinOp; NFC

Author: aqjune

llvm/test/Transforms/InstSimplify/distribute.ll

@@ -0,0 +1,32 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
+; RUN: opt < %s -instsimplify -S | FileCheck %s
+
+; %result = x & (1 ^ sel) = (x & 1) ^ (x & sel)
+;         = x ^ (select cond, false, false)
+;         = x ^ false = x
+;
+define i1 @f(i1 %cond, i1 noundef %x, i1 %y, i1 %z) {
+; CHECK-LABEL: @f(
+; CHECK-NEXT:    ret i1 [[X:%.*]]
+;
+  %notx = xor i1 %x, 1
+  %lhs = and i1 %notx, %y
+  %rhs = and i1 %notx, %z
+  %sel = select i1 %cond, i1 %lhs, i1 %rhs
+  %op1 = xor i1 1, %sel
+  %result = and i1 %x, %op1
+  ret i1 %result
+}
+
+define i1 @f_dontfold(i1 %cond, i1 %x, i1 %y, i1 %z) {
+; CHECK-LABEL: @f_dontfold(
+; CHECK-NEXT:    ret i1 [[X:%.*]]
+;
+  %notx = xor i1 %x, 1
+  %lhs = and i1 %notx, %y
+  %rhs = and i1 %notx, %z
+  %sel = select i1 %cond, i1 %lhs, i1 %rhs
+  %op1 = xor i1 1, %sel
+  %result = and i1 %x, %op1
+  ret i1 %result
+}