[GVN] Add test for #116668 (NFC)

Author: nikic

llvm/test/Transforms/GVN/setjmp.ll

@@ -0,0 +1,37 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --version 5
+; RUN: opt -S -passes=gvn < %s | FileCheck %s
+
+declare i32 @setjmp() returns_twice
+declare void @longjmp()
+declare ptr @malloc(i64)
+
+; FIXME: This is a miscompile.
+define i32 @test() {
+; CHECK-LABEL: define i32 @test() {
+; CHECK-NEXT:    [[MALLOC:%.*]] = call noalias ptr @malloc(i64 4)
+; CHECK-NEXT:    store i32 10, ptr [[MALLOC]], align 4
+; CHECK-NEXT:    [[SJ:%.*]] = call i32 @setjmp()
+; CHECK-NEXT:    [[CMP:%.*]] = icmp eq i32 [[SJ]], 0
+; CHECK-NEXT:    br i1 [[CMP]], label %[[IF_THEN:.*]], label %[[IF_END:.*]]
+; CHECK:       [[IF_THEN]]:
+; CHECK-NEXT:    store i32 20, ptr [[MALLOC]], align 4
+; CHECK-NEXT:    call void @longjmp()
+; CHECK-NEXT:    unreachable
+; CHECK:       [[IF_END]]:
+; CHECK-NEXT:    ret i32 10
+;
+  %malloc = call noalias ptr @malloc(i64 4)
+  store i32 10, ptr %malloc, align 4
+  %sj = call i32 @setjmp()
+  %cmp = icmp eq i32 %sj, 0
+  br i1 %cmp, label %if.then, label %if.end
+
+if.then:
+  store i32 20, ptr %malloc
+  call void @longjmp()
+  unreachable
+
+if.end:
+  %res = load i32, ptr %malloc
+  ret i32 %res
+}