[clang] [KeyInstr][Clang] Do stmt atom (PR #134644)

[Orlando Cazalet-Hyams via cfe-commits]

================
@@ -0,0 +1,33 @@
+// RUN: %clang_cc1 -gkey-instructions -x c++ -std=c++17 %s -debug-info-kind=line-tables-only -emit-llvm -o - \
+// RUN: | FileCheck %s --implicit-check-not atomGroup --implicit-check-not atomRank
+
+// RUN: %clang_cc1 -gkey-instructions -x c %s -debug-info-kind=line-tables-only -emit-llvm -o -  \
+// RUN: | FileCheck %s --implicit-check-not atomGroup --implicit-check-not atomRank
+
+// Perennial quesiton: should the `dec` be in its own source atom or not
+// (currently it is).
+
+// Another question - we've made the cmp and br separate source atoms for
+// now, to match existing behaviour in this case:
+// 1. do {
+// 2.   something();
+// 3. }
+// 4. while (--A);
+// Non key instruction behaviour is: 2, 4[, 3, 2, 4]+
+// The cond br is associated with the brace on line 3 and the cmp is line 4;
+// if they were in the same atom group we'd step just: 2, 3[, 2, 3]+
+// FIXME: We could arguably improve the behaviour by making them the same
+// group but having the cmp higher precedence, resulting in: 2, 4[, 2, 4]+.
----------------
OCHyams wrote:

Done, in our internal issue tracker

https://github.com/llvm/llvm-project/pull/134644