Skip to content

[KeyInstr][Clang] Do stmt atom #134644

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Open
wants to merge 1 commit into
base: users/OCHyams/ki-clang-switch
Choose a base branch
from
Open

[KeyInstr][Clang] Do stmt atom #134644

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
10 changes: 9 additions & 1 deletion clang/lib/CodeGen/CGStmt.cpp
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -1242,9 +1242,17 @@ void CodeGenFunction::EmitDoStmt(const DoStmt &S,
// As long as the condition is true, iterate the loop.
if (EmitBoolCondBranch) {
uint64_t BackedgeCount = getProfileCount(S.getBody()) - ParentCount;
Builder.CreateCondBr(
auto *I = Builder.CreateCondBr(
BoolCondVal, LoopBody, LoopExit.getBlock(),
createProfileWeightsForLoop(S.getCond(), BackedgeCount));

// 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 (no jumping to the brace).
if (auto *I = dyn_cast<llvm::Instruction>(BoolCondVal))
addInstToNewSourceAtom(I, nullptr);
addInstToNewSourceAtom(I, nullptr);
}

LoopStack.pop();
Expand Down
33 changes: 33 additions & 0 deletions clang/test/KeyInstructions/do.c
View file
Open in desktop
Original file line number Diff line number Diff line change
@@ -0,0 +1,33 @@
// RUN: %clang -gkey-instructions -x c++ -std=c++17 %s -gmlt -S -emit-llvm -o - \
// RUN: | FileCheck %s --implicit-check-not atomGroup --implicit-check-not atomRank

// RUN: %clang -gkey-instructions -x c %s -gmlt -S -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]+.

void a(int A) {
// CHECK: %dec = add nsw i32 %0, -1, !dbg [[G1R2:!.*]]
// CHECK: store i32 %dec, ptr %A.addr{{.*}}, !dbg [[G1R1:!.*]]
// CHECK: %tobool = icmp ne i32 %dec, 0, !dbg [[G2R1:!.*]]
// CHECK: br i1 %tobool, label %do.body, label %do.end, !dbg [[G3R1:!.*]], !llvm.loop
do { } while (--A);
}

// CHECK: [[G1R2]] = !DILocation({{.*}}, atomGroup: 1, atomRank: 2)
// CHECK: [[G1R1]] = !DILocation({{.*}}, atomGroup: 1, atomRank: 1)
// CHECK: [[G2R1]] = !DILocation({{.*}}, atomGroup: 2, atomRank: 1)
// CHECK: [[G3R1]] = !DILocation({{.*}}, atomGroup: 3, atomRank: 1)
Loading