[clang] [KeyInstr][Clang] Atomic ops atoms (PR #141624)

[Jeremy Morse via cfe-commits]

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@@ -0,0 +1,162 @@
+// RUN: %clang_cc1 -triple x86_64-linux-gnu -gkey-instructions -x c++ -std=c++17 %s -debug-info-kind=line-tables-only -emit-llvm -o - -gno-column-info \
+// RUN: | FileCheck %s --implicit-check-not atomGroup --implicit-check-not atomRank
+// RUN: %clang_cc1 -triple x86_64-linux-gnu -gkey-instructions -x c %s -debug-info-kind=line-tables-only -emit-llvm -o - -gno-column-info \
+// RUN: | FileCheck %s --implicit-check-not atomGroup --implicit-check-not atomRank
+
+// Check that atomic handling code gets Key Instruction annotations.
+
+_Atomic(unsigned int) x;
+unsigned int y;
+void fun() {
+  unsigned int r1 = __c11_atomic_fetch_add(&x,- 1, __ATOMIC_RELAXED);
+// CHECK:      store i32 -1, ptr %.atomictmp, align 4,                !dbg [[LINE11_G2R1:!.*]]
+// CHECK-NEXT: %0 = load i32, ptr %.atomictmp, align 4,               !dbg [[LINE11:!.*]]
+// CHECK-NEXT: %1 = atomicrmw add ptr @x, i32 %0 monotonic, align 4,  !dbg [[LINE11_G2R2:!.*]]
+// CHECK-NEXT: store i32 %1, ptr %atomic-temp, align 4,               !dbg [[LINE11_G2R1]]
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jmorse wrote:

So it's deliberate + desirable that both this and the earlier store of -1 are group-two-rank-one? (I suppose the buoy-based KIs will float the breakpoint upwards)

https://github.com/llvm/llvm-project/pull/141624