[clang] [CIR] Upstream new SetBitfieldOp for handling C and C++ struct bitfields (PR #147609)

[Erich Keane via cfe-commits]

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@@ -42,3 +42,73 @@ int init(S* s) {
 //OGCG:   [[TMP2:%.*]] = load i32, ptr [[TMP1]], align 4
 //OGCG:   [[TMP3:%.*]] = shl i32 [[TMP2]], 15
 //OGCG:   [[TMP4:%.*]] = ashr i32 [[TMP3]], 15
+
+
+void load(S* s) {
+    s->a = -4;
+    s->b = 42;
+    s->c = -12345;
+}
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erichkeane wrote:

Could you do a `s->a = s->c; ` sorta thing in one of the tests? 

https://github.com/llvm/llvm-project/pull/147609