[GlobalOpt] Add tests with reads from globals with constant exprs.

Author: fhahn

llvm/test/Transforms/GlobalOpt/read-with-constexpr-users.ll

@@ -0,0 +1,36 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --check-globals all --version 5
+; RUN: opt -p globalopt -S %s | FileCheck %s
+
+@G = internal global [2 x i64 ] zeroinitializer
+@H = internal global [2 x i64 ] zeroinitializer
+
+;.
+; CHECK: @G = internal global [2 x i64] zeroinitializer
+; CHECK: @H = internal global [2 x i64] zeroinitializer
+;.
+define i64 @G_used_by_gep_inttoptr_exprs() {
+; CHECK-LABEL: define i64 @G_used_by_gep_inttoptr_exprs() local_unnamed_addr {
+; CHECK-NEXT:    [[L:%.*]] = load i64, ptr @G, align 8
+; CHECK-NEXT:    [[GEP:%.*]] = getelementptr i8, ptr inttoptr (i64 add (i64 ptrtoint (ptr getelementptr inbounds nuw (i8, ptr @G, i64 16) to i64), i64 8) to ptr), i64 1
+; CHECK-NEXT:    [[C:%.*]] = icmp eq ptr [[GEP]], @G
+; CHECK-NEXT:    [[SEL:%.*]] = select i1 [[C]], i64 [[L]], i64 9
+; CHECK-NEXT:    ret i64 [[SEL]]
+;
+  %l = load i64, ptr @G, align 8
+  %gep = getelementptr i8, ptr inttoptr (i64 add (i64 ptrtoint (ptr getelementptr inbounds nuw (i8, ptr @G, i64 16) to i64), i64 8) to ptr), i64 1
+  %c = icmp eq ptr %gep, @G
+  %sel = select i1 %c, i64 %l, i64 9
+  ret i64 %sel
+}
+
+define i64 @H_constexpr_stored(ptr %p) {
+; CHECK-LABEL: define i64 @H_constexpr_stored(
+; CHECK-SAME: ptr [[P:%.*]]) local_unnamed_addr {
+; CHECK-NEXT:    [[L:%.*]] = load i64, ptr @H, align 8
+; CHECK-NEXT:    store i64 ptrtoint (ptr getelementptr inbounds nuw (i8, ptr @H, i64 16) to i64), ptr [[P]], align 4
+; CHECK-NEXT:    ret i64 [[L]]
+;
+  %l = load i64, ptr @H, align 8
+  store i64 ptrtoint (ptr getelementptr inbounds nuw (i8, ptr @H, i64 16) to i64), ptr %p
+  ret i64 %l
+}