[KeyInstr][Clang] Multiple assignment (x = y = z)

Author: OCHyams

clang/lib/CodeGen/CGExprScalar.cpp

@@ -4973,6 +4973,7 @@ llvm::Value *CodeGenFunction::EmitWithOriginalRHSBitfieldAssignment(
 }
 
 Value *ScalarExprEmitter::VisitBinAssign(const BinaryOperator *E) {
+  ApplyAtomGroup Grp(CGF.getDebugInfo());
   bool Ignore = TestAndClearIgnoreResultAssign();
 
   Value *RHS;

clang/test/KeyInstructions/assign.cpp

@@ -2,8 +2,22 @@
 // RUN: | FileCheck %s --implicit-check-not atomGroup --implicit-check-not atomRank
 
 unsigned long long g;
-void fun() { g = 0; }
-
+void fun() {
 // CHECK: store i64 0, ptr @g{{.*}}, !dbg [[G1R1:!.*]]
+    g = 0;
+
+// Treat the two assignments as two atoms.
+//
+// FIXME: Because of the atomGroup implementation the load can only be
+// associated with one of the two stores, despite being a good backup
+// loction for both.
+// CHECK-NEXT: %0 = load i64, ptr @g{{.*}}, !dbg [[G2R2:!.*]]
+// CHECK-NEXT: store i64 %0, ptr @g{{.*}}, !dbg [[G3R1:!.*]]
+// CHECK-NEXT: store i64 %0, ptr @g{{.*}}, !dbg [[G2R1:!.*]]
+    g = g = g;
+}
 
 // CHECK: [[G1R1]] = !DILocation({{.*}}, atomGroup: 1, atomRank: 1)
+// CHECK: [[G2R2]] = !DILocation({{.*}}, atomGroup: 2, atomRank: 2)
+// CHECK: [[G3R1]] = !DILocation({{.*}}, atomGroup: 3, atomRank: 1)
+// CHECK: [[G2R1]] = !DILocation({{.*}}, atomGroup: 2, atomRank: 1)