Revert "[KeyInstr][Clang] For range stmt atoms"

[OCHyams]

Reverts #134647

Bot failure:
https://lab.llvm.org/buildbot/#/builders/144/builds/26730/steps/6/logs/FAIL__Clang__terminate-statements_cpp

[llvmbot]

@llvm/pr-subscribers-clang

@llvm/pr-subscribers-clang-codegen

Author: Orlando Cazalet-Hyams (OCHyams)

Changes

Reverts llvm/llvm-project#134647

Bot failure:
https://lab.llvm.org/buildbot/#/builders/144/builds/26730/steps/6/logs/FAIL__Clang__terminate-statements_cpp

---

Full diff: https://github.com/llvm/llvm-project/pull/142630.diff

2 Files Affected:

• (modified) clang/lib/CodeGen/CGStmt.cpp (+1-16)
• (removed) clang/test/DebugInfo/KeyInstructions/for-range.cpp (-87)

diff --git a/clang/lib/CodeGen/CGStmt.cpp b/clang/lib/CodeGen/CGStmt.cpp
index 8739455481767..205a57cbab31a 100644
--- a/clang/lib/CodeGen/CGStmt.cpp
+++ b/clang/lib/CodeGen/CGStmt.cpp
@@ -1483,14 +1483,7 @@ CodeGenFunction::EmitCXXForRangeStmt(const CXXForRangeStmt &S,
   if (!Weights && CGM.getCodeGenOpts().OptimizationLevel)
     BoolCondVal = emitCondLikelihoodViaExpectIntrinsic(
         BoolCondVal, Stmt::getLikelihood(S.getBody()));
-  auto *I = Builder.CreateCondBr(BoolCondVal, ForBody, ExitBlock, Weights);
-  // Key Instructions: Emit the condition and branch as separate atoms to
-  // match existing loop stepping behaviour. FIXME: We could have the branch as
-  // the backup location for the condition, which would probably be a better
-  // experience.
-  if (auto *CondI = dyn_cast<llvm::Instruction>(BoolCondVal))
-    addInstToNewSourceAtom(CondI, nullptr);
-  addInstToNewSourceAtom(I, nullptr);
+  Builder.CreateCondBr(BoolCondVal, ForBody, ExitBlock, Weights);
 
   if (ExitBlock != LoopExit.getBlock()) {
     EmitBlock(ExitBlock);
@@ -1516,10 +1509,6 @@ CodeGenFunction::EmitCXXForRangeStmt(const CXXForRangeStmt &S,
     EmitStmt(S.getBody());
   }
 
-  // The last block in the loop's body (which unconditionally branches to the
-  // `inc` block if there is one).
-  auto *FinalBodyBB = Builder.GetInsertBlock();
-
   EmitStopPoint(&S);
   // If there is an increment, emit it next.
   EmitBlock(Continue.getBlock());
@@ -1543,10 +1532,6 @@ CodeGenFunction::EmitCXXForRangeStmt(const CXXForRangeStmt &S,
 
   if (CGM.shouldEmitConvergenceTokens())
     ConvergenceTokenStack.pop_back();
-
-  // We want the for closing brace to be step-able on to match existing
-  // behaviour.
-  addInstToNewSourceAtom(FinalBodyBB->getTerminator(), nullptr);
 }
 
 void CodeGenFunction::EmitReturnOfRValue(RValue RV, QualType Ty) {
diff --git a/clang/test/DebugInfo/KeyInstructions/for-range.cpp b/clang/test/DebugInfo/KeyInstructions/for-range.cpp
deleted file mode 100644
index 921060f3b2462..0000000000000
--- a/clang/test/DebugInfo/KeyInstructions/for-range.cpp
+++ /dev/null
@@ -1,87 +0,0 @@
-// RUN: %clang_cc1 -triple x86_64-linux-gnu  -gkey-instructions %s -debug-info-kind=line-tables-only -emit-llvm -o - \
-// RUN: | FileCheck %s
-
-// Perennial question: should the inc be its own source atom or not
-// (currently it is).
-
-// FIXME: See do.c and while.c regarding cmp and cond br groups.
-
-// The stores in the setup (stores to __RANGE1, __BEGIN1, __END1) are all
-// marked as Key. Unclear whether that's desirable. Keep for now as that's
-// least risky (at worst it introduces an unnecessary step while debugging,
-// as opposed to potentially losing one we want).
-
-// Check the conditional branch (and the condition) in FOR_COND and
-// unconditional branch in FOR_BODY are Key Instructions.
-
-struct Range {
-    int *begin();
-    int *end();
-} r;
-
-// CHECK-LABEL: define dso_local void @_Z1av(
-// CHECK-SAME: ) #[[ATTR0:[0-9]+]] !dbg [[DBG10:![0-9]+]] {
-// CHECK-NEXT:  [[ENTRY:.*:]]
-// CHECK-NEXT:    [[__RANGE1:%.*]] = alloca ptr, align 8
-// CHECK-NEXT:    [[__BEGIN1:%.*]] = alloca ptr, align 8
-// CHECK-NEXT:    [[__END1:%.*]] = alloca ptr, align 8
-// CHECK-NEXT:    [[I:%.*]] = alloca i32, align 4
-// CHECK-NEXT:    store ptr @r, ptr [[__RANGE1]], align 8, !dbg [[DBG14:![0-9]+]]
-// CHECK-NEXT:    [[CALL:%.*]] = call noundef ptr @_ZN5Range5beginEv(ptr noundef nonnull align 1 dereferenceable(1) @r), !dbg [[DBG15:![0-9]+]]
-// CHECK-NEXT:    store ptr [[CALL]], ptr [[__BEGIN1]], align 8, !dbg [[DBG16:![0-9]+]]
-// CHECK-NEXT:    [[CALL1:%.*]] = call noundef ptr @_ZN5Range3endEv(ptr noundef nonnull align 1 dereferenceable(1) @r), !dbg [[DBG17:![0-9]+]]
-// CHECK-NEXT:    store ptr [[CALL1]], ptr [[__END1]], align 8, !dbg [[DBG18:![0-9]+]]
-// CHECK-NEXT:    br label %[[FOR_COND:.*]], !dbg [[DBG19:![0-9]+]]
-// CHECK:       [[FOR_COND]]:
-// CHECK-NEXT:    [[TMP0:%.*]] = load ptr, ptr [[__BEGIN1]], align 8, !dbg [[DBG19]]
-// CHECK-NEXT:    [[TMP1:%.*]] = load ptr, ptr [[__END1]], align 8, !dbg [[DBG19]]
-// CHECK-NEXT:    [[CMP:%.*]] = icmp ne ptr [[TMP0]], [[TMP1]], !dbg [[DBG20:![0-9]+]]
-// CHECK-NEXT:    br i1 [[CMP]], label %[[FOR_BODY:.*]], label %[[FOR_END:.*]], !dbg [[DBG21:![0-9]+]]
-// CHECK:       [[FOR_BODY]]:
-// CHECK-NEXT:    [[TMP2:%.*]] = load ptr, ptr [[__BEGIN1]], align 8, !dbg [[DBG19]]
-// CHECK-NEXT:    [[TMP3:%.*]] = load i32, ptr [[TMP2]], align 4, !dbg [[DBG22:![0-9]+]]
-// CHECK-NEXT:    store i32 [[TMP3]], ptr [[I]], align 4, !dbg [[DBG23:![0-9]+]]
-// CHECK-NEXT:    br label %[[FOR_INC:.*]], !dbg [[DBG24:![0-9]+]]
-// CHECK:       [[FOR_INC]]:
-// CHECK-NEXT:    [[TMP4:%.*]] = load ptr, ptr [[__BEGIN1]], align 8, !dbg [[DBG19]]
-// CHECK-NEXT:    [[INCDEC_PTR:%.*]] = getelementptr inbounds nuw i32, ptr [[TMP4]], i32 1, !dbg [[DBG25:![0-9]+]]
-// CHECK-NEXT:    store ptr [[INCDEC_PTR]], ptr [[__BEGIN1]], align 8, !dbg [[DBG26:![0-9]+]]
-// CHECK-NEXT:    br label %[[FOR_COND]], !dbg [[DBG19]], !llvm.loop
-// CHECK:       [[FOR_END]]:
-// CHECK-NEXT:    ret void, !dbg [[DBG30:![0-9]+]]
-//
-void a() {
-  for (int i: r)
-    ;
-}
-
-// - Check the branch out of the body gets an atom group (and gets it correct
-// if there's ctrl-flow in the body).
-void b() {
-  for (int i: r) {
-    if (i)
-      ;
-// CHECK: entry:
-// CHECK: if.end:
-// CHECK-NEXT: br label %for.inc, !dbg [[b_br:!.*]]
-  }
-}
-
-//.
-// CHECK: [[DBG14]] = !DILocation({{.*}}, atomGroup: 1, atomRank: 1)
-// CHECK: [[DBG15]] = !DILocation({{.*}}, atomGroup: 2, atomRank: 2)
-// CHECK: [[DBG16]] = !DILocation({{.*}}, atomGroup: 2, atomRank: 1)
-// CHECK: [[DBG17]] = !DILocation({{.*}}, atomGroup: 3, atomRank: 2)
-// CHECK: [[DBG18]] = !DILocation({{.*}}, atomGroup: 3, atomRank: 1)
-// CHECK: [[DBG19]] = !DILocation({{.*}})
-// CHECK: [[DBG20]] = !DILocation({{.*}}, atomGroup: 4, atomRank: 1)
-// CHECK: [[DBG21]] = !DILocation({{.*}}, atomGroup: 5, atomRank: 1)
-// CHECK: [[DBG22]] = !DILocation({{.*}}, atomGroup: 6, atomRank: 2)
-// CHECK: [[DBG23]] = !DILocation({{.*}}, atomGroup: 6, atomRank: 1)
-// CHECK: [[DBG24]] = !DILocation({{.*}} atomGroup: 8, atomRank: 1)
-// CHECK: [[DBG25]] = !DILocation({{.*}}, atomGroup: 7, atomRank: 2)
-// CHECK: [[DBG26]] = !DILocation({{.*}}, atomGroup: 7, atomRank: 1)
-// CHECK: [[DBG30]] = !DILocation({{.*}})
-//
-// CHECK: [[b_br]] = !DILocation({{.*}}, atomGroup: [[#]], atomRank: [[#]])
-//.