[InstCombine] Add tests for folding (add X, (sext/zext (icmp eq X, C))); NFC

Author: goldsteinn

llvm/test/Transforms/InstCombine/fold-ext-eq-c-with-op.ll

@@ -0,0 +1,61 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
+; RUN: opt < %s -passes=instcombine -S | FileCheck %s
+
+declare void @use.i8(i8)
+define i8 @fold_add_zext_eq_0(i8 %x) {
+; CHECK-LABEL: @fold_add_zext_eq_0(
+; CHECK-NEXT:    [[X_EQ:%.*]] = icmp eq i8 [[X:%.*]], 0
+; CHECK-NEXT:    [[X_EQ_EXT:%.*]] = zext i1 [[X_EQ]] to i8
+; CHECK-NEXT:    [[R:%.*]] = add i8 [[X_EQ_EXT]], [[X]]
+; CHECK-NEXT:    ret i8 [[R]]
+;
+  %x_eq = icmp eq i8 %x, 0
+  %x_eq_ext = zext i1 %x_eq to i8
+  %r = add i8 %x, %x_eq_ext
+  ret i8 %r
+}
+
+define <2 x i8> @fold_add_sext_eq_4_6(<2 x i6> %xx) {
+; CHECK-LABEL: @fold_add_sext_eq_4_6(
+; CHECK-NEXT:    [[X:%.*]] = zext <2 x i6> [[XX:%.*]] to <2 x i8>
+; CHECK-NEXT:    [[X_EQ:%.*]] = icmp eq <2 x i8> [[X]], <i8 4, i8 -127>
+; CHECK-NEXT:    [[X_EQ_EXT:%.*]] = sext <2 x i1> [[X_EQ]] to <2 x i8>
+; CHECK-NEXT:    [[R:%.*]] = add nsw <2 x i8> [[X_EQ_EXT]], [[X]]
+; CHECK-NEXT:    ret <2 x i8> [[R]]
+;
+  %x = zext <2 x i6> %xx to <2 x i8>
+  %x_eq = icmp eq <2 x i8> %x, <i8 4, i8 129>
+  %x_eq_ext = sext <2 x i1> %x_eq to <2 x i8>
+  %r = add <2 x i8> %x_eq_ext, %x
+  ret <2 x i8> %r
+}
+
+define i8 @fold_add_zext_eq_0_fail_multiuse_exp(i8 %x) {
+; CHECK-LABEL: @fold_add_zext_eq_0_fail_multiuse_exp(
+; CHECK-NEXT:    [[X_EQ:%.*]] = icmp eq i8 [[X:%.*]], 0
+; CHECK-NEXT:    [[X_EQ_EXT:%.*]] = zext i1 [[X_EQ]] to i8
+; CHECK-NEXT:    [[R:%.*]] = add i8 [[X_EQ_EXT]], [[X]]
+; CHECK-NEXT:    call void @use.i8(i8 [[X_EQ_EXT]])
+; CHECK-NEXT:    ret i8 [[R]]
+;
+  %x_eq = icmp eq i8 %x, 0
+  %x_eq_ext = zext i1 %x_eq to i8
+  %r = add i8 %x, %x_eq_ext
+  call void @use.i8(i8 %x_eq_ext)
+  ret i8 %r
+}
+
+define i8 @fold_add_sext_eq_4_fail_wrong_cond(i8 %x, i8 %y) {
+; CHECK-LABEL: @fold_add_sext_eq_4_fail_wrong_cond(
+; CHECK-NEXT:    [[X_EQ:%.*]] = icmp eq i8 [[Y:%.*]], 4
+; CHECK-NEXT:    [[X_EQ_EXT:%.*]] = sext i1 [[X_EQ]] to i8
+; CHECK-NEXT:    [[R:%.*]] = add i8 [[X_EQ_EXT]], [[X:%.*]]
+; CHECK-NEXT:    call void @use.i8(i8 [[X_EQ_EXT]])
+; CHECK-NEXT:    ret i8 [[R]]
+;
+  %x_eq = icmp eq i8 %y, 4
+  %x_eq_ext = sext i1 %x_eq to i8
+  %r = add i8 %x, %x_eq_ext
+  call void @use.i8(i8 %x_eq_ext)
+  ret i8 %r
+}