[NFC] Added testcase for PR40750

Author: davidbolvansky

llvm/test/Transforms/PhaseOrdering/pr40750.ll

@@ -0,0 +1,32 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
+; RUN: opt -simplifycfg -simplifycfg-require-and-preserve-domtree=1 -instcombine -S < %s | FileCheck %s
+
+%struct.test = type { i8, [3 x i8] }
+
+define i32 @get(%struct.test* nocapture readonly %arg) {
+; CHECK-LABEL: @get(
+; CHECK-NEXT:  bb:
+; CHECK-NEXT:    [[I:%.*]] = getelementptr inbounds [[STRUCT_TEST:%.*]], %struct.test* [[ARG:%.*]], i64 0, i32 0
+; CHECK-NEXT:    [[I1:%.*]] = load i8, i8* [[I]], align 4
+; CHECK-NEXT:    [[TMP0:%.*]] = and i8 [[I1]], 3
+; CHECK-NEXT:    [[TMP1:%.*]] = icmp ne i8 [[TMP0]], 0
+; CHECK-NEXT:    [[I9:%.*]] = zext i1 [[TMP1]] to i32
+; CHECK-NEXT:    ret i32 [[I9]]
+;
+bb:
+  %i = getelementptr inbounds %struct.test, %struct.test* %arg, i64 0, i32 0
+  %i1 = load i8, i8* %i, align 4
+  %i2 = and i8 %i1, 1
+  %i3 = icmp eq i8 %i2, 0
+  br i1 %i3, label %bb4, label %bb8
+
+bb4:
+  %i5 = lshr i8 %i1, 1
+  %i6 = and i8 %i5, 1
+  %i7 = zext i8 %i6 to i32
+  br label %bb8
+
+bb8:
+  %i9 = phi i32 [ 1, %bb ], [ %i7, %bb4 ]
+  ret i32 %i9
+}