Fix redundant load of bit-fields on assignment (to get the updated
value).
- Use extra argument to EmitStoreThroughLValue to provide place to
write update bit-field value if caller requires it.
- This fixes several FIXMEs.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@59615 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/test/CodeGen/bitfield-assign.c b/test/CodeGen/bitfield-assign.c
new file mode 100644
index 0000000..fc163b4
--- /dev/null
+++ b/test/CodeGen/bitfield-assign.c
@@ -0,0 +1,44 @@
+/* Check that the result of a bitfield assignment is properly
+ truncated and does not generate a redundant load. */
+
+/* Check that we get one load for each simple assign and two for the
+ compound assign (load the old value before the add then load again
+ to store back). Also check that our g0 pattern is good. */
+// RUN: clang -O0 -emit-llvm -o %t %s &&
+// RUN: grep 'load ' %t | count 5 &&
+// RUN: grep "@g0" %t | count 4 &&
+
+// Check that we got the right value.
+// RUN: clang -O3 -emit-llvm -o %t %s &&
+// RUN: grep 'load ' %t | count 0 &&
+// RUN: grep "@g0" %t | count 0
+
+struct s0 {
+ int f0 : 2;
+ _Bool f1 : 1;
+ unsigned f2 : 2;
+};
+
+int g0();
+
+void f0(void) {
+ struct s0 s;
+ if ((s.f0 = 3) != -1) g0();
+}
+
+void f1(void) {
+ struct s0 s;
+ if ((s.f1 = 3) != 1) g0();
+}
+
+void f2(void) {
+ struct s0 s;
+ if ((s.f2 = 3) != 3) g0();
+}
+
+void f3(void) {
+ struct s0 s;
+ // Just check this one for load counts.
+ s.f0 += 3;
+}
+